mirror of
https://github.com/RPCS3/llvm.git
synced 2024-12-23 04:28:30 +00:00
aebac50e77
SimplifyLibCalls/2005-05-20-sprintf-crash.ll git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23430 91177308-0d34-0410-b5e6-96231b3b80d8
2046 lines
70 KiB
C++
2046 lines
70 KiB
C++
//===- SimplifyLibCalls.cpp - Optimize specific well-known library calls --===//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file was developed by Reid Spencer and is distributed under the
|
|
// University of Illinois Open Source License. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// This file implements a module pass that applies a variety of small
|
|
// optimizations for calls to specific well-known function calls (e.g. runtime
|
|
// library functions). For example, a call to the function "exit(3)" that
|
|
// occurs within the main() function can be transformed into a simple "return 3"
|
|
// instruction. Any optimization that takes this form (replace call to library
|
|
// function with simpler code that provides the same result) belongs in this
|
|
// file.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#define DEBUG_TYPE "simplify-libcalls"
|
|
#include "llvm/Constants.h"
|
|
#include "llvm/DerivedTypes.h"
|
|
#include "llvm/Instructions.h"
|
|
#include "llvm/Module.h"
|
|
#include "llvm/Pass.h"
|
|
#include "llvm/ADT/hash_map"
|
|
#include "llvm/ADT/Statistic.h"
|
|
#include "llvm/Support/Debug.h"
|
|
#include "llvm/Target/TargetData.h"
|
|
#include "llvm/Transforms/IPO.h"
|
|
#include <iostream>
|
|
using namespace llvm;
|
|
|
|
namespace {
|
|
|
|
/// This statistic keeps track of the total number of library calls that have
|
|
/// been simplified regardless of which call it is.
|
|
Statistic<> SimplifiedLibCalls("simplify-libcalls",
|
|
"Number of library calls simplified");
|
|
|
|
// Forward declarations
|
|
class LibCallOptimization;
|
|
class SimplifyLibCalls;
|
|
|
|
/// This hash map is populated by the constructor for LibCallOptimization class.
|
|
/// Therefore all subclasses are registered here at static initialization time
|
|
/// and this list is what the SimplifyLibCalls pass uses to apply the individual
|
|
/// optimizations to the call sites.
|
|
/// @brief The list of optimizations deriving from LibCallOptimization
|
|
static hash_map<std::string,LibCallOptimization*> optlist;
|
|
|
|
/// This class is the abstract base class for the set of optimizations that
|
|
/// corresponds to one library call. The SimplifyLibCalls pass will call the
|
|
/// ValidateCalledFunction method to ask the optimization if a given Function
|
|
/// is the kind that the optimization can handle. If the subclass returns true,
|
|
/// then SImplifyLibCalls will also call the OptimizeCall method to perform,
|
|
/// or attempt to perform, the optimization(s) for the library call. Otherwise,
|
|
/// OptimizeCall won't be called. Subclasses are responsible for providing the
|
|
/// name of the library call (strlen, strcpy, etc.) to the LibCallOptimization
|
|
/// constructor. This is used to efficiently select which call instructions to
|
|
/// optimize. The criteria for a "lib call" is "anything with well known
|
|
/// semantics", typically a library function that is defined by an international
|
|
/// standard. Because the semantics are well known, the optimizations can
|
|
/// generally short-circuit actually calling the function if there's a simpler
|
|
/// way (e.g. strlen(X) can be reduced to a constant if X is a constant global).
|
|
/// @brief Base class for library call optimizations
|
|
class LibCallOptimization
|
|
{
|
|
public:
|
|
/// The \p fname argument must be the name of the library function being
|
|
/// optimized by the subclass.
|
|
/// @brief Constructor that registers the optimization.
|
|
LibCallOptimization(const char* fname, const char* description )
|
|
: func_name(fname)
|
|
#ifndef NDEBUG
|
|
, occurrences("simplify-libcalls",description)
|
|
#endif
|
|
{
|
|
// Register this call optimizer in the optlist (a hash_map)
|
|
optlist[fname] = this;
|
|
}
|
|
|
|
/// @brief Deregister from the optlist
|
|
virtual ~LibCallOptimization() { optlist.erase(func_name); }
|
|
|
|
/// The implementation of this function in subclasses should determine if
|
|
/// \p F is suitable for the optimization. This method is called by
|
|
/// SimplifyLibCalls::runOnModule to short circuit visiting all the call
|
|
/// sites of such a function if that function is not suitable in the first
|
|
/// place. If the called function is suitabe, this method should return true;
|
|
/// false, otherwise. This function should also perform any lazy
|
|
/// initialization that the LibCallOptimization needs to do, if its to return
|
|
/// true. This avoids doing initialization until the optimizer is actually
|
|
/// going to be called upon to do some optimization.
|
|
/// @brief Determine if the function is suitable for optimization
|
|
virtual bool ValidateCalledFunction(
|
|
const Function* F, ///< The function that is the target of call sites
|
|
SimplifyLibCalls& SLC ///< The pass object invoking us
|
|
) = 0;
|
|
|
|
/// The implementations of this function in subclasses is the heart of the
|
|
/// SimplifyLibCalls algorithm. Sublcasses of this class implement
|
|
/// OptimizeCall to determine if (a) the conditions are right for optimizing
|
|
/// the call and (b) to perform the optimization. If an action is taken
|
|
/// against ci, the subclass is responsible for returning true and ensuring
|
|
/// that ci is erased from its parent.
|
|
/// @brief Optimize a call, if possible.
|
|
virtual bool OptimizeCall(
|
|
CallInst* ci, ///< The call instruction that should be optimized.
|
|
SimplifyLibCalls& SLC ///< The pass object invoking us
|
|
) = 0;
|
|
|
|
/// @brief Get the name of the library call being optimized
|
|
const char * getFunctionName() const { return func_name; }
|
|
|
|
#ifndef NDEBUG
|
|
/// @brief Called by SimplifyLibCalls to update the occurrences statistic.
|
|
void succeeded() { DEBUG(++occurrences); }
|
|
#endif
|
|
|
|
private:
|
|
const char* func_name; ///< Name of the library call we optimize
|
|
#ifndef NDEBUG
|
|
Statistic<> occurrences; ///< debug statistic (-debug-only=simplify-libcalls)
|
|
#endif
|
|
};
|
|
|
|
/// This class is an LLVM Pass that applies each of the LibCallOptimization
|
|
/// instances to all the call sites in a module, relatively efficiently. The
|
|
/// purpose of this pass is to provide optimizations for calls to well-known
|
|
/// functions with well-known semantics, such as those in the c library. The
|
|
/// class provides the basic infrastructure for handling runOnModule. Whenever
|
|
/// this pass finds a function call, it asks the appropriate optimizer to
|
|
/// validate the call (ValidateLibraryCall). If it is validated, then
|
|
/// the OptimizeCall method is also called.
|
|
/// @brief A ModulePass for optimizing well-known function calls.
|
|
class SimplifyLibCalls : public ModulePass
|
|
{
|
|
public:
|
|
/// We need some target data for accurate signature details that are
|
|
/// target dependent. So we require target data in our AnalysisUsage.
|
|
/// @brief Require TargetData from AnalysisUsage.
|
|
virtual void getAnalysisUsage(AnalysisUsage& Info) const
|
|
{
|
|
// Ask that the TargetData analysis be performed before us so we can use
|
|
// the target data.
|
|
Info.addRequired<TargetData>();
|
|
}
|
|
|
|
/// For this pass, process all of the function calls in the module, calling
|
|
/// ValidateLibraryCall and OptimizeCall as appropriate.
|
|
/// @brief Run all the lib call optimizations on a Module.
|
|
virtual bool runOnModule(Module &M)
|
|
{
|
|
reset(M);
|
|
|
|
bool result = false;
|
|
|
|
// The call optimizations can be recursive. That is, the optimization might
|
|
// generate a call to another function which can also be optimized. This way
|
|
// we make the LibCallOptimization instances very specific to the case they
|
|
// handle. It also means we need to keep running over the function calls in
|
|
// the module until we don't get any more optimizations possible.
|
|
bool found_optimization = false;
|
|
do
|
|
{
|
|
found_optimization = false;
|
|
for (Module::iterator FI = M.begin(), FE = M.end(); FI != FE; ++FI)
|
|
{
|
|
// All the "well-known" functions are external and have external linkage
|
|
// because they live in a runtime library somewhere and were (probably)
|
|
// not compiled by LLVM. So, we only act on external functions that
|
|
// have external linkage and non-empty uses.
|
|
if (!FI->isExternal() || !FI->hasExternalLinkage() || FI->use_empty())
|
|
continue;
|
|
|
|
// Get the optimization class that pertains to this function
|
|
LibCallOptimization* CO = optlist[FI->getName().c_str()];
|
|
if (!CO)
|
|
continue;
|
|
|
|
// Make sure the called function is suitable for the optimization
|
|
if (!CO->ValidateCalledFunction(FI,*this))
|
|
continue;
|
|
|
|
// Loop over each of the uses of the function
|
|
for (Value::use_iterator UI = FI->use_begin(), UE = FI->use_end();
|
|
UI != UE ; )
|
|
{
|
|
// If the use of the function is a call instruction
|
|
if (CallInst* CI = dyn_cast<CallInst>(*UI++))
|
|
{
|
|
// Do the optimization on the LibCallOptimization.
|
|
if (CO->OptimizeCall(CI,*this))
|
|
{
|
|
++SimplifiedLibCalls;
|
|
found_optimization = result = true;
|
|
#ifndef NDEBUG
|
|
CO->succeeded();
|
|
#endif
|
|
}
|
|
}
|
|
}
|
|
}
|
|
} while (found_optimization);
|
|
return result;
|
|
}
|
|
|
|
/// @brief Return the *current* module we're working on.
|
|
Module* getModule() const { return M; }
|
|
|
|
/// @brief Return the *current* target data for the module we're working on.
|
|
TargetData* getTargetData() const { return TD; }
|
|
|
|
/// @brief Return the size_t type -- syntactic shortcut
|
|
const Type* getIntPtrType() const { return TD->getIntPtrType(); }
|
|
|
|
/// @brief Return a Function* for the fputc libcall
|
|
Function* get_fputc(const Type* FILEptr_type)
|
|
{
|
|
if (!fputc_func)
|
|
{
|
|
std::vector<const Type*> args;
|
|
args.push_back(Type::IntTy);
|
|
args.push_back(FILEptr_type);
|
|
FunctionType* fputc_type =
|
|
FunctionType::get(Type::IntTy, args, false);
|
|
fputc_func = M->getOrInsertFunction("fputc",fputc_type);
|
|
}
|
|
return fputc_func;
|
|
}
|
|
|
|
/// @brief Return a Function* for the fwrite libcall
|
|
Function* get_fwrite(const Type* FILEptr_type)
|
|
{
|
|
if (!fwrite_func)
|
|
{
|
|
std::vector<const Type*> args;
|
|
args.push_back(PointerType::get(Type::SByteTy));
|
|
args.push_back(TD->getIntPtrType());
|
|
args.push_back(TD->getIntPtrType());
|
|
args.push_back(FILEptr_type);
|
|
FunctionType* fwrite_type =
|
|
FunctionType::get(TD->getIntPtrType(), args, false);
|
|
fwrite_func = M->getOrInsertFunction("fwrite",fwrite_type);
|
|
}
|
|
return fwrite_func;
|
|
}
|
|
|
|
/// @brief Return a Function* for the sqrt libcall
|
|
Function* get_sqrt()
|
|
{
|
|
if (!sqrt_func)
|
|
{
|
|
std::vector<const Type*> args;
|
|
args.push_back(Type::DoubleTy);
|
|
FunctionType* sqrt_type =
|
|
FunctionType::get(Type::DoubleTy, args, false);
|
|
sqrt_func = M->getOrInsertFunction("sqrt",sqrt_type);
|
|
}
|
|
return sqrt_func;
|
|
}
|
|
|
|
/// @brief Return a Function* for the strlen libcall
|
|
Function* get_strcpy()
|
|
{
|
|
if (!strcpy_func)
|
|
{
|
|
std::vector<const Type*> args;
|
|
args.push_back(PointerType::get(Type::SByteTy));
|
|
args.push_back(PointerType::get(Type::SByteTy));
|
|
FunctionType* strcpy_type =
|
|
FunctionType::get(PointerType::get(Type::SByteTy), args, false);
|
|
strcpy_func = M->getOrInsertFunction("strcpy",strcpy_type);
|
|
}
|
|
return strcpy_func;
|
|
}
|
|
|
|
/// @brief Return a Function* for the strlen libcall
|
|
Function* get_strlen()
|
|
{
|
|
if (!strlen_func)
|
|
{
|
|
std::vector<const Type*> args;
|
|
args.push_back(PointerType::get(Type::SByteTy));
|
|
FunctionType* strlen_type =
|
|
FunctionType::get(TD->getIntPtrType(), args, false);
|
|
strlen_func = M->getOrInsertFunction("strlen",strlen_type);
|
|
}
|
|
return strlen_func;
|
|
}
|
|
|
|
/// @brief Return a Function* for the memchr libcall
|
|
Function* get_memchr()
|
|
{
|
|
if (!memchr_func)
|
|
{
|
|
std::vector<const Type*> args;
|
|
args.push_back(PointerType::get(Type::SByteTy));
|
|
args.push_back(Type::IntTy);
|
|
args.push_back(TD->getIntPtrType());
|
|
FunctionType* memchr_type = FunctionType::get(
|
|
PointerType::get(Type::SByteTy), args, false);
|
|
memchr_func = M->getOrInsertFunction("memchr",memchr_type);
|
|
}
|
|
return memchr_func;
|
|
}
|
|
|
|
/// @brief Return a Function* for the memcpy libcall
|
|
Function* get_memcpy() {
|
|
if (!memcpy_func) {
|
|
const Type *SBP = PointerType::get(Type::SByteTy);
|
|
memcpy_func = M->getOrInsertFunction("llvm.memcpy", Type::VoidTy,SBP, SBP,
|
|
Type::UIntTy, Type::UIntTy, 0);
|
|
}
|
|
return memcpy_func;
|
|
}
|
|
|
|
Function* get_floorf() {
|
|
if (!floorf_func)
|
|
floorf_func = M->getOrInsertFunction("floorf", Type::FloatTy,
|
|
Type::FloatTy, 0);
|
|
return floorf_func;
|
|
}
|
|
|
|
private:
|
|
/// @brief Reset our cached data for a new Module
|
|
void reset(Module& mod)
|
|
{
|
|
M = &mod;
|
|
TD = &getAnalysis<TargetData>();
|
|
fputc_func = 0;
|
|
fwrite_func = 0;
|
|
memcpy_func = 0;
|
|
memchr_func = 0;
|
|
sqrt_func = 0;
|
|
strcpy_func = 0;
|
|
strlen_func = 0;
|
|
floorf_func = 0;
|
|
}
|
|
|
|
private:
|
|
Function* fputc_func; ///< Cached fputc function
|
|
Function* fwrite_func; ///< Cached fwrite function
|
|
Function* memcpy_func; ///< Cached llvm.memcpy function
|
|
Function* memchr_func; ///< Cached memchr function
|
|
Function* sqrt_func; ///< Cached sqrt function
|
|
Function* strcpy_func; ///< Cached strcpy function
|
|
Function* strlen_func; ///< Cached strlen function
|
|
Function* floorf_func; ///< Cached floorf function
|
|
Module* M; ///< Cached Module
|
|
TargetData* TD; ///< Cached TargetData
|
|
};
|
|
|
|
// Register the pass
|
|
RegisterOpt<SimplifyLibCalls>
|
|
X("simplify-libcalls","Simplify well-known library calls");
|
|
|
|
} // anonymous namespace
|
|
|
|
// The only public symbol in this file which just instantiates the pass object
|
|
ModulePass *llvm::createSimplifyLibCallsPass()
|
|
{
|
|
return new SimplifyLibCalls();
|
|
}
|
|
|
|
// Classes below here, in the anonymous namespace, are all subclasses of the
|
|
// LibCallOptimization class, each implementing all optimizations possible for a
|
|
// single well-known library call. Each has a static singleton instance that
|
|
// auto registers it into the "optlist" global above.
|
|
namespace {
|
|
|
|
// Forward declare utility functions.
|
|
bool getConstantStringLength(Value* V, uint64_t& len, ConstantArray** A = 0 );
|
|
Value *CastToCStr(Value *V, Instruction &IP);
|
|
|
|
/// This LibCallOptimization will find instances of a call to "exit" that occurs
|
|
/// within the "main" function and change it to a simple "ret" instruction with
|
|
/// the same value passed to the exit function. When this is done, it splits the
|
|
/// basic block at the exit(3) call and deletes the call instruction.
|
|
/// @brief Replace calls to exit in main with a simple return
|
|
struct ExitInMainOptimization : public LibCallOptimization
|
|
{
|
|
ExitInMainOptimization() : LibCallOptimization("exit",
|
|
"Number of 'exit' calls simplified") {}
|
|
virtual ~ExitInMainOptimization() {}
|
|
|
|
// Make sure the called function looks like exit (int argument, int return
|
|
// type, external linkage, not varargs).
|
|
virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC)
|
|
{
|
|
if (f->arg_size() >= 1)
|
|
if (f->arg_begin()->getType()->isInteger())
|
|
return true;
|
|
return false;
|
|
}
|
|
|
|
virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& SLC)
|
|
{
|
|
// To be careful, we check that the call to exit is coming from "main", that
|
|
// main has external linkage, and the return type of main and the argument
|
|
// to exit have the same type.
|
|
Function *from = ci->getParent()->getParent();
|
|
if (from->hasExternalLinkage())
|
|
if (from->getReturnType() == ci->getOperand(1)->getType())
|
|
if (from->getName() == "main")
|
|
{
|
|
// Okay, time to actually do the optimization. First, get the basic
|
|
// block of the call instruction
|
|
BasicBlock* bb = ci->getParent();
|
|
|
|
// Create a return instruction that we'll replace the call with.
|
|
// Note that the argument of the return is the argument of the call
|
|
// instruction.
|
|
ReturnInst* ri = new ReturnInst(ci->getOperand(1), ci);
|
|
|
|
// Split the block at the call instruction which places it in a new
|
|
// basic block.
|
|
bb->splitBasicBlock(ci);
|
|
|
|
// The block split caused a branch instruction to be inserted into
|
|
// the end of the original block, right after the return instruction
|
|
// that we put there. That's not a valid block, so delete the branch
|
|
// instruction.
|
|
bb->getInstList().pop_back();
|
|
|
|
// Now we can finally get rid of the call instruction which now lives
|
|
// in the new basic block.
|
|
ci->eraseFromParent();
|
|
|
|
// Optimization succeeded, return true.
|
|
return true;
|
|
}
|
|
// We didn't pass the criteria for this optimization so return false
|
|
return false;
|
|
}
|
|
} ExitInMainOptimizer;
|
|
|
|
/// This LibCallOptimization will simplify a call to the strcat library
|
|
/// function. The simplification is possible only if the string being
|
|
/// concatenated is a constant array or a constant expression that results in
|
|
/// a constant string. In this case we can replace it with strlen + llvm.memcpy
|
|
/// of the constant string. Both of these calls are further reduced, if possible
|
|
/// on subsequent passes.
|
|
/// @brief Simplify the strcat library function.
|
|
struct StrCatOptimization : public LibCallOptimization
|
|
{
|
|
public:
|
|
/// @brief Default constructor
|
|
StrCatOptimization() : LibCallOptimization("strcat",
|
|
"Number of 'strcat' calls simplified") {}
|
|
|
|
public:
|
|
/// @breif Destructor
|
|
virtual ~StrCatOptimization() {}
|
|
|
|
/// @brief Make sure that the "strcat" function has the right prototype
|
|
virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC)
|
|
{
|
|
if (f->getReturnType() == PointerType::get(Type::SByteTy))
|
|
if (f->arg_size() == 2)
|
|
{
|
|
Function::const_arg_iterator AI = f->arg_begin();
|
|
if (AI++->getType() == PointerType::get(Type::SByteTy))
|
|
if (AI->getType() == PointerType::get(Type::SByteTy))
|
|
{
|
|
// Indicate this is a suitable call type.
|
|
return true;
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
|
|
/// @brief Optimize the strcat library function
|
|
virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& SLC)
|
|
{
|
|
// Extract some information from the instruction
|
|
Module* M = ci->getParent()->getParent()->getParent();
|
|
Value* dest = ci->getOperand(1);
|
|
Value* src = ci->getOperand(2);
|
|
|
|
// Extract the initializer (while making numerous checks) from the
|
|
// source operand of the call to strcat. If we get null back, one of
|
|
// a variety of checks in get_GVInitializer failed
|
|
uint64_t len = 0;
|
|
if (!getConstantStringLength(src,len))
|
|
return false;
|
|
|
|
// Handle the simple, do-nothing case
|
|
if (len == 0)
|
|
{
|
|
ci->replaceAllUsesWith(dest);
|
|
ci->eraseFromParent();
|
|
return true;
|
|
}
|
|
|
|
// Increment the length because we actually want to memcpy the null
|
|
// terminator as well.
|
|
len++;
|
|
|
|
// We need to find the end of the destination string. That's where the
|
|
// memory is to be moved to. We just generate a call to strlen (further
|
|
// optimized in another pass). Note that the SLC.get_strlen() call
|
|
// caches the Function* for us.
|
|
CallInst* strlen_inst =
|
|
new CallInst(SLC.get_strlen(), dest, dest->getName()+".len",ci);
|
|
|
|
// Now that we have the destination's length, we must index into the
|
|
// destination's pointer to get the actual memcpy destination (end of
|
|
// the string .. we're concatenating).
|
|
std::vector<Value*> idx;
|
|
idx.push_back(strlen_inst);
|
|
GetElementPtrInst* gep =
|
|
new GetElementPtrInst(dest,idx,dest->getName()+".indexed",ci);
|
|
|
|
// We have enough information to now generate the memcpy call to
|
|
// do the concatenation for us.
|
|
std::vector<Value*> vals;
|
|
vals.push_back(gep); // destination
|
|
vals.push_back(ci->getOperand(2)); // source
|
|
vals.push_back(ConstantUInt::get(Type::UIntTy,len)); // length
|
|
vals.push_back(ConstantUInt::get(Type::UIntTy,1)); // alignment
|
|
new CallInst(SLC.get_memcpy(), vals, "", ci);
|
|
|
|
// Finally, substitute the first operand of the strcat call for the
|
|
// strcat call itself since strcat returns its first operand; and,
|
|
// kill the strcat CallInst.
|
|
ci->replaceAllUsesWith(dest);
|
|
ci->eraseFromParent();
|
|
return true;
|
|
}
|
|
} StrCatOptimizer;
|
|
|
|
/// This LibCallOptimization will simplify a call to the strchr library
|
|
/// function. It optimizes out cases where the arguments are both constant
|
|
/// and the result can be determined statically.
|
|
/// @brief Simplify the strcmp library function.
|
|
struct StrChrOptimization : public LibCallOptimization
|
|
{
|
|
public:
|
|
StrChrOptimization() : LibCallOptimization("strchr",
|
|
"Number of 'strchr' calls simplified") {}
|
|
virtual ~StrChrOptimization() {}
|
|
|
|
/// @brief Make sure that the "strchr" function has the right prototype
|
|
virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC)
|
|
{
|
|
if (f->getReturnType() == PointerType::get(Type::SByteTy) &&
|
|
f->arg_size() == 2)
|
|
return true;
|
|
return false;
|
|
}
|
|
|
|
/// @brief Perform the strchr optimizations
|
|
virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& SLC)
|
|
{
|
|
// If there aren't three operands, bail
|
|
if (ci->getNumOperands() != 3)
|
|
return false;
|
|
|
|
// Check that the first argument to strchr is a constant array of sbyte.
|
|
// If it is, get the length and data, otherwise return false.
|
|
uint64_t len = 0;
|
|
ConstantArray* CA;
|
|
if (!getConstantStringLength(ci->getOperand(1),len,&CA))
|
|
return false;
|
|
|
|
// Check that the second argument to strchr is a constant int, return false
|
|
// if it isn't
|
|
ConstantSInt* CSI = dyn_cast<ConstantSInt>(ci->getOperand(2));
|
|
if (!CSI)
|
|
{
|
|
// Just lower this to memchr since we know the length of the string as
|
|
// it is constant.
|
|
Function* f = SLC.get_memchr();
|
|
std::vector<Value*> args;
|
|
args.push_back(ci->getOperand(1));
|
|
args.push_back(ci->getOperand(2));
|
|
args.push_back(ConstantUInt::get(SLC.getIntPtrType(),len));
|
|
ci->replaceAllUsesWith( new CallInst(f,args,ci->getName(),ci));
|
|
ci->eraseFromParent();
|
|
return true;
|
|
}
|
|
|
|
// Get the character we're looking for
|
|
int64_t chr = CSI->getValue();
|
|
|
|
// Compute the offset
|
|
uint64_t offset = 0;
|
|
bool char_found = false;
|
|
for (uint64_t i = 0; i < len; ++i)
|
|
{
|
|
if (ConstantSInt* CI = dyn_cast<ConstantSInt>(CA->getOperand(i)))
|
|
{
|
|
// Check for the null terminator
|
|
if (CI->isNullValue())
|
|
break; // we found end of string
|
|
else if (CI->getValue() == chr)
|
|
{
|
|
char_found = true;
|
|
offset = i;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
// strchr(s,c) -> offset_of_in(c,s)
|
|
// (if c is a constant integer and s is a constant string)
|
|
if (char_found)
|
|
{
|
|
std::vector<Value*> indices;
|
|
indices.push_back(ConstantUInt::get(Type::ULongTy,offset));
|
|
GetElementPtrInst* GEP = new GetElementPtrInst(ci->getOperand(1),indices,
|
|
ci->getOperand(1)->getName()+".strchr",ci);
|
|
ci->replaceAllUsesWith(GEP);
|
|
}
|
|
else
|
|
ci->replaceAllUsesWith(
|
|
ConstantPointerNull::get(PointerType::get(Type::SByteTy)));
|
|
|
|
ci->eraseFromParent();
|
|
return true;
|
|
}
|
|
} StrChrOptimizer;
|
|
|
|
/// This LibCallOptimization will simplify a call to the strcmp library
|
|
/// function. It optimizes out cases where one or both arguments are constant
|
|
/// and the result can be determined statically.
|
|
/// @brief Simplify the strcmp library function.
|
|
struct StrCmpOptimization : public LibCallOptimization
|
|
{
|
|
public:
|
|
StrCmpOptimization() : LibCallOptimization("strcmp",
|
|
"Number of 'strcmp' calls simplified") {}
|
|
virtual ~StrCmpOptimization() {}
|
|
|
|
/// @brief Make sure that the "strcmp" function has the right prototype
|
|
virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC)
|
|
{
|
|
if (f->getReturnType() == Type::IntTy && f->arg_size() == 2)
|
|
return true;
|
|
return false;
|
|
}
|
|
|
|
/// @brief Perform the strcmp optimization
|
|
virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& SLC)
|
|
{
|
|
// First, check to see if src and destination are the same. If they are,
|
|
// then the optimization is to replace the CallInst with a constant 0
|
|
// because the call is a no-op.
|
|
Value* s1 = ci->getOperand(1);
|
|
Value* s2 = ci->getOperand(2);
|
|
if (s1 == s2)
|
|
{
|
|
// strcmp(x,x) -> 0
|
|
ci->replaceAllUsesWith(ConstantInt::get(Type::IntTy,0));
|
|
ci->eraseFromParent();
|
|
return true;
|
|
}
|
|
|
|
bool isstr_1 = false;
|
|
uint64_t len_1 = 0;
|
|
ConstantArray* A1;
|
|
if (getConstantStringLength(s1,len_1,&A1))
|
|
{
|
|
isstr_1 = true;
|
|
if (len_1 == 0)
|
|
{
|
|
// strcmp("",x) -> *x
|
|
LoadInst* load =
|
|
new LoadInst(CastToCStr(s2,*ci), ci->getName()+".load",ci);
|
|
CastInst* cast =
|
|
new CastInst(load,Type::IntTy,ci->getName()+".int",ci);
|
|
ci->replaceAllUsesWith(cast);
|
|
ci->eraseFromParent();
|
|
return true;
|
|
}
|
|
}
|
|
|
|
bool isstr_2 = false;
|
|
uint64_t len_2 = 0;
|
|
ConstantArray* A2;
|
|
if (getConstantStringLength(s2,len_2,&A2))
|
|
{
|
|
isstr_2 = true;
|
|
if (len_2 == 0)
|
|
{
|
|
// strcmp(x,"") -> *x
|
|
LoadInst* load =
|
|
new LoadInst(CastToCStr(s1,*ci),ci->getName()+".val",ci);
|
|
CastInst* cast =
|
|
new CastInst(load,Type::IntTy,ci->getName()+".int",ci);
|
|
ci->replaceAllUsesWith(cast);
|
|
ci->eraseFromParent();
|
|
return true;
|
|
}
|
|
}
|
|
|
|
if (isstr_1 && isstr_2)
|
|
{
|
|
// strcmp(x,y) -> cnst (if both x and y are constant strings)
|
|
std::string str1 = A1->getAsString();
|
|
std::string str2 = A2->getAsString();
|
|
int result = strcmp(str1.c_str(), str2.c_str());
|
|
ci->replaceAllUsesWith(ConstantSInt::get(Type::IntTy,result));
|
|
ci->eraseFromParent();
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
} StrCmpOptimizer;
|
|
|
|
/// This LibCallOptimization will simplify a call to the strncmp library
|
|
/// function. It optimizes out cases where one or both arguments are constant
|
|
/// and the result can be determined statically.
|
|
/// @brief Simplify the strncmp library function.
|
|
struct StrNCmpOptimization : public LibCallOptimization
|
|
{
|
|
public:
|
|
StrNCmpOptimization() : LibCallOptimization("strncmp",
|
|
"Number of 'strncmp' calls simplified") {}
|
|
virtual ~StrNCmpOptimization() {}
|
|
|
|
/// @brief Make sure that the "strncmp" function has the right prototype
|
|
virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC)
|
|
{
|
|
if (f->getReturnType() == Type::IntTy && f->arg_size() == 3)
|
|
return true;
|
|
return false;
|
|
}
|
|
|
|
/// @brief Perform the strncpy optimization
|
|
virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& SLC)
|
|
{
|
|
// First, check to see if src and destination are the same. If they are,
|
|
// then the optimization is to replace the CallInst with a constant 0
|
|
// because the call is a no-op.
|
|
Value* s1 = ci->getOperand(1);
|
|
Value* s2 = ci->getOperand(2);
|
|
if (s1 == s2)
|
|
{
|
|
// strncmp(x,x,l) -> 0
|
|
ci->replaceAllUsesWith(ConstantInt::get(Type::IntTy,0));
|
|
ci->eraseFromParent();
|
|
return true;
|
|
}
|
|
|
|
// Check the length argument, if it is Constant zero then the strings are
|
|
// considered equal.
|
|
uint64_t len_arg = 0;
|
|
bool len_arg_is_const = false;
|
|
if (ConstantInt* len_CI = dyn_cast<ConstantInt>(ci->getOperand(3)))
|
|
{
|
|
len_arg_is_const = true;
|
|
len_arg = len_CI->getRawValue();
|
|
if (len_arg == 0)
|
|
{
|
|
// strncmp(x,y,0) -> 0
|
|
ci->replaceAllUsesWith(ConstantInt::get(Type::IntTy,0));
|
|
ci->eraseFromParent();
|
|
return true;
|
|
}
|
|
}
|
|
|
|
bool isstr_1 = false;
|
|
uint64_t len_1 = 0;
|
|
ConstantArray* A1;
|
|
if (getConstantStringLength(s1,len_1,&A1))
|
|
{
|
|
isstr_1 = true;
|
|
if (len_1 == 0)
|
|
{
|
|
// strncmp("",x) -> *x
|
|
LoadInst* load = new LoadInst(s1,ci->getName()+".load",ci);
|
|
CastInst* cast =
|
|
new CastInst(load,Type::IntTy,ci->getName()+".int",ci);
|
|
ci->replaceAllUsesWith(cast);
|
|
ci->eraseFromParent();
|
|
return true;
|
|
}
|
|
}
|
|
|
|
bool isstr_2 = false;
|
|
uint64_t len_2 = 0;
|
|
ConstantArray* A2;
|
|
if (getConstantStringLength(s2,len_2,&A2))
|
|
{
|
|
isstr_2 = true;
|
|
if (len_2 == 0)
|
|
{
|
|
// strncmp(x,"") -> *x
|
|
LoadInst* load = new LoadInst(s2,ci->getName()+".val",ci);
|
|
CastInst* cast =
|
|
new CastInst(load,Type::IntTy,ci->getName()+".int",ci);
|
|
ci->replaceAllUsesWith(cast);
|
|
ci->eraseFromParent();
|
|
return true;
|
|
}
|
|
}
|
|
|
|
if (isstr_1 && isstr_2 && len_arg_is_const)
|
|
{
|
|
// strncmp(x,y,const) -> constant
|
|
std::string str1 = A1->getAsString();
|
|
std::string str2 = A2->getAsString();
|
|
int result = strncmp(str1.c_str(), str2.c_str(), len_arg);
|
|
ci->replaceAllUsesWith(ConstantSInt::get(Type::IntTy,result));
|
|
ci->eraseFromParent();
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
} StrNCmpOptimizer;
|
|
|
|
/// This LibCallOptimization will simplify a call to the strcpy library
|
|
/// function. Two optimizations are possible:
|
|
/// (1) If src and dest are the same and not volatile, just return dest
|
|
/// (2) If the src is a constant then we can convert to llvm.memmove
|
|
/// @brief Simplify the strcpy library function.
|
|
struct StrCpyOptimization : public LibCallOptimization
|
|
{
|
|
public:
|
|
StrCpyOptimization() : LibCallOptimization("strcpy",
|
|
"Number of 'strcpy' calls simplified") {}
|
|
virtual ~StrCpyOptimization() {}
|
|
|
|
/// @brief Make sure that the "strcpy" function has the right prototype
|
|
virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC)
|
|
{
|
|
if (f->getReturnType() == PointerType::get(Type::SByteTy))
|
|
if (f->arg_size() == 2)
|
|
{
|
|
Function::const_arg_iterator AI = f->arg_begin();
|
|
if (AI++->getType() == PointerType::get(Type::SByteTy))
|
|
if (AI->getType() == PointerType::get(Type::SByteTy))
|
|
{
|
|
// Indicate this is a suitable call type.
|
|
return true;
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
|
|
/// @brief Perform the strcpy optimization
|
|
virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& SLC)
|
|
{
|
|
// First, check to see if src and destination are the same. If they are,
|
|
// then the optimization is to replace the CallInst with the destination
|
|
// because the call is a no-op. Note that this corresponds to the
|
|
// degenerate strcpy(X,X) case which should have "undefined" results
|
|
// according to the C specification. However, it occurs sometimes and
|
|
// we optimize it as a no-op.
|
|
Value* dest = ci->getOperand(1);
|
|
Value* src = ci->getOperand(2);
|
|
if (dest == src)
|
|
{
|
|
ci->replaceAllUsesWith(dest);
|
|
ci->eraseFromParent();
|
|
return true;
|
|
}
|
|
|
|
// Get the length of the constant string referenced by the second operand,
|
|
// the "src" parameter. Fail the optimization if we can't get the length
|
|
// (note that getConstantStringLength does lots of checks to make sure this
|
|
// is valid).
|
|
uint64_t len = 0;
|
|
if (!getConstantStringLength(ci->getOperand(2),len))
|
|
return false;
|
|
|
|
// If the constant string's length is zero we can optimize this by just
|
|
// doing a store of 0 at the first byte of the destination
|
|
if (len == 0)
|
|
{
|
|
new StoreInst(ConstantInt::get(Type::SByteTy,0),ci->getOperand(1),ci);
|
|
ci->replaceAllUsesWith(dest);
|
|
ci->eraseFromParent();
|
|
return true;
|
|
}
|
|
|
|
// Increment the length because we actually want to memcpy the null
|
|
// terminator as well.
|
|
len++;
|
|
|
|
// Extract some information from the instruction
|
|
Module* M = ci->getParent()->getParent()->getParent();
|
|
|
|
// We have enough information to now generate the memcpy call to
|
|
// do the concatenation for us.
|
|
std::vector<Value*> vals;
|
|
vals.push_back(dest); // destination
|
|
vals.push_back(src); // source
|
|
vals.push_back(ConstantUInt::get(Type::UIntTy,len)); // length
|
|
vals.push_back(ConstantUInt::get(Type::UIntTy,1)); // alignment
|
|
new CallInst(SLC.get_memcpy(), vals, "", ci);
|
|
|
|
// Finally, substitute the first operand of the strcat call for the
|
|
// strcat call itself since strcat returns its first operand; and,
|
|
// kill the strcat CallInst.
|
|
ci->replaceAllUsesWith(dest);
|
|
ci->eraseFromParent();
|
|
return true;
|
|
}
|
|
} StrCpyOptimizer;
|
|
|
|
/// This LibCallOptimization will simplify a call to the strlen library
|
|
/// function by replacing it with a constant value if the string provided to
|
|
/// it is a constant array.
|
|
/// @brief Simplify the strlen library function.
|
|
struct StrLenOptimization : public LibCallOptimization
|
|
{
|
|
StrLenOptimization() : LibCallOptimization("strlen",
|
|
"Number of 'strlen' calls simplified") {}
|
|
virtual ~StrLenOptimization() {}
|
|
|
|
/// @brief Make sure that the "strlen" function has the right prototype
|
|
virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC)
|
|
{
|
|
if (f->getReturnType() == SLC.getTargetData()->getIntPtrType())
|
|
if (f->arg_size() == 1)
|
|
if (Function::const_arg_iterator AI = f->arg_begin())
|
|
if (AI->getType() == PointerType::get(Type::SByteTy))
|
|
return true;
|
|
return false;
|
|
}
|
|
|
|
/// @brief Perform the strlen optimization
|
|
virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& SLC)
|
|
{
|
|
// Make sure we're dealing with an sbyte* here.
|
|
Value* str = ci->getOperand(1);
|
|
if (str->getType() != PointerType::get(Type::SByteTy))
|
|
return false;
|
|
|
|
// Does the call to strlen have exactly one use?
|
|
if (ci->hasOneUse())
|
|
// Is that single use a binary operator?
|
|
if (BinaryOperator* bop = dyn_cast<BinaryOperator>(ci->use_back()))
|
|
// Is it compared against a constant integer?
|
|
if (ConstantInt* CI = dyn_cast<ConstantInt>(bop->getOperand(1)))
|
|
{
|
|
// Get the value the strlen result is compared to
|
|
uint64_t val = CI->getRawValue();
|
|
|
|
// If its compared against length 0 with == or !=
|
|
if (val == 0 &&
|
|
(bop->getOpcode() == Instruction::SetEQ ||
|
|
bop->getOpcode() == Instruction::SetNE))
|
|
{
|
|
// strlen(x) != 0 -> *x != 0
|
|
// strlen(x) == 0 -> *x == 0
|
|
LoadInst* load = new LoadInst(str,str->getName()+".first",ci);
|
|
BinaryOperator* rbop = BinaryOperator::create(bop->getOpcode(),
|
|
load, ConstantSInt::get(Type::SByteTy,0),
|
|
bop->getName()+".strlen", ci);
|
|
bop->replaceAllUsesWith(rbop);
|
|
bop->eraseFromParent();
|
|
ci->eraseFromParent();
|
|
return true;
|
|
}
|
|
}
|
|
|
|
// Get the length of the constant string operand
|
|
uint64_t len = 0;
|
|
if (!getConstantStringLength(ci->getOperand(1),len))
|
|
return false;
|
|
|
|
// strlen("xyz") -> 3 (for example)
|
|
const Type *Ty = SLC.getTargetData()->getIntPtrType();
|
|
if (Ty->isSigned())
|
|
ci->replaceAllUsesWith(ConstantSInt::get(Ty, len));
|
|
else
|
|
ci->replaceAllUsesWith(ConstantUInt::get(Ty, len));
|
|
|
|
ci->eraseFromParent();
|
|
return true;
|
|
}
|
|
} StrLenOptimizer;
|
|
|
|
/// This LibCallOptimization will simplify a call to the memcpy library
|
|
/// function by expanding it out to a single store of size 0, 1, 2, 4, or 8
|
|
/// bytes depending on the length of the string and the alignment. Additional
|
|
/// optimizations are possible in code generation (sequence of immediate store)
|
|
/// @brief Simplify the memcpy library function.
|
|
struct LLVMMemCpyOptimization : public LibCallOptimization
|
|
{
|
|
/// @brief Default Constructor
|
|
LLVMMemCpyOptimization() : LibCallOptimization("llvm.memcpy",
|
|
"Number of 'llvm.memcpy' calls simplified") {}
|
|
|
|
protected:
|
|
/// @brief Subclass Constructor
|
|
LLVMMemCpyOptimization(const char* fname, const char* desc)
|
|
: LibCallOptimization(fname, desc) {}
|
|
public:
|
|
/// @brief Destructor
|
|
virtual ~LLVMMemCpyOptimization() {}
|
|
|
|
/// @brief Make sure that the "memcpy" function has the right prototype
|
|
virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& TD)
|
|
{
|
|
// Just make sure this has 4 arguments per LLVM spec.
|
|
return (f->arg_size() == 4);
|
|
}
|
|
|
|
/// Because of alignment and instruction information that we don't have, we
|
|
/// leave the bulk of this to the code generators. The optimization here just
|
|
/// deals with a few degenerate cases where the length of the string and the
|
|
/// alignment match the sizes of our intrinsic types so we can do a load and
|
|
/// store instead of the memcpy call.
|
|
/// @brief Perform the memcpy optimization.
|
|
virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& TD)
|
|
{
|
|
// Make sure we have constant int values to work with
|
|
ConstantInt* LEN = dyn_cast<ConstantInt>(ci->getOperand(3));
|
|
if (!LEN)
|
|
return false;
|
|
ConstantInt* ALIGN = dyn_cast<ConstantInt>(ci->getOperand(4));
|
|
if (!ALIGN)
|
|
return false;
|
|
|
|
// If the length is larger than the alignment, we can't optimize
|
|
uint64_t len = LEN->getRawValue();
|
|
uint64_t alignment = ALIGN->getRawValue();
|
|
if (alignment == 0)
|
|
alignment = 1; // Alignment 0 is identity for alignment 1
|
|
if (len > alignment)
|
|
return false;
|
|
|
|
// Get the type we will cast to, based on size of the string
|
|
Value* dest = ci->getOperand(1);
|
|
Value* src = ci->getOperand(2);
|
|
Type* castType = 0;
|
|
switch (len)
|
|
{
|
|
case 0:
|
|
// memcpy(d,s,0,a) -> noop
|
|
ci->eraseFromParent();
|
|
return true;
|
|
case 1: castType = Type::SByteTy; break;
|
|
case 2: castType = Type::ShortTy; break;
|
|
case 4: castType = Type::IntTy; break;
|
|
case 8: castType = Type::LongTy; break;
|
|
default:
|
|
return false;
|
|
}
|
|
|
|
// Cast source and dest to the right sized primitive and then load/store
|
|
CastInst* SrcCast =
|
|
new CastInst(src,PointerType::get(castType),src->getName()+".cast",ci);
|
|
CastInst* DestCast =
|
|
new CastInst(dest,PointerType::get(castType),dest->getName()+".cast",ci);
|
|
LoadInst* LI = new LoadInst(SrcCast,SrcCast->getName()+".val",ci);
|
|
StoreInst* SI = new StoreInst(LI, DestCast, ci);
|
|
ci->eraseFromParent();
|
|
return true;
|
|
}
|
|
} LLVMMemCpyOptimizer;
|
|
|
|
/// This LibCallOptimization will simplify a call to the memmove library
|
|
/// function. It is identical to MemCopyOptimization except for the name of
|
|
/// the intrinsic.
|
|
/// @brief Simplify the memmove library function.
|
|
struct LLVMMemMoveOptimization : public LLVMMemCpyOptimization
|
|
{
|
|
/// @brief Default Constructor
|
|
LLVMMemMoveOptimization() : LLVMMemCpyOptimization("llvm.memmove",
|
|
"Number of 'llvm.memmove' calls simplified") {}
|
|
|
|
} LLVMMemMoveOptimizer;
|
|
|
|
/// This LibCallOptimization will simplify a call to the memset library
|
|
/// function by expanding it out to a single store of size 0, 1, 2, 4, or 8
|
|
/// bytes depending on the length argument.
|
|
struct LLVMMemSetOptimization : public LibCallOptimization
|
|
{
|
|
/// @brief Default Constructor
|
|
LLVMMemSetOptimization() : LibCallOptimization("llvm.memset",
|
|
"Number of 'llvm.memset' calls simplified") {}
|
|
|
|
public:
|
|
/// @brief Destructor
|
|
virtual ~LLVMMemSetOptimization() {}
|
|
|
|
/// @brief Make sure that the "memset" function has the right prototype
|
|
virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& TD)
|
|
{
|
|
// Just make sure this has 3 arguments per LLVM spec.
|
|
return (f->arg_size() == 4);
|
|
}
|
|
|
|
/// Because of alignment and instruction information that we don't have, we
|
|
/// leave the bulk of this to the code generators. The optimization here just
|
|
/// deals with a few degenerate cases where the length parameter is constant
|
|
/// and the alignment matches the sizes of our intrinsic types so we can do
|
|
/// store instead of the memcpy call. Other calls are transformed into the
|
|
/// llvm.memset intrinsic.
|
|
/// @brief Perform the memset optimization.
|
|
virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& TD)
|
|
{
|
|
// Make sure we have constant int values to work with
|
|
ConstantInt* LEN = dyn_cast<ConstantInt>(ci->getOperand(3));
|
|
if (!LEN)
|
|
return false;
|
|
ConstantInt* ALIGN = dyn_cast<ConstantInt>(ci->getOperand(4));
|
|
if (!ALIGN)
|
|
return false;
|
|
|
|
// Extract the length and alignment
|
|
uint64_t len = LEN->getRawValue();
|
|
uint64_t alignment = ALIGN->getRawValue();
|
|
|
|
// Alignment 0 is identity for alignment 1
|
|
if (alignment == 0)
|
|
alignment = 1;
|
|
|
|
// If the length is zero, this is a no-op
|
|
if (len == 0)
|
|
{
|
|
// memset(d,c,0,a) -> noop
|
|
ci->eraseFromParent();
|
|
return true;
|
|
}
|
|
|
|
// If the length is larger than the alignment, we can't optimize
|
|
if (len > alignment)
|
|
return false;
|
|
|
|
// Make sure we have a constant ubyte to work with so we can extract
|
|
// the value to be filled.
|
|
ConstantUInt* FILL = dyn_cast<ConstantUInt>(ci->getOperand(2));
|
|
if (!FILL)
|
|
return false;
|
|
if (FILL->getType() != Type::UByteTy)
|
|
return false;
|
|
|
|
// memset(s,c,n) -> store s, c (for n=1,2,4,8)
|
|
|
|
// Extract the fill character
|
|
uint64_t fill_char = FILL->getValue();
|
|
uint64_t fill_value = fill_char;
|
|
|
|
// Get the type we will cast to, based on size of memory area to fill, and
|
|
// and the value we will store there.
|
|
Value* dest = ci->getOperand(1);
|
|
Type* castType = 0;
|
|
switch (len)
|
|
{
|
|
case 1:
|
|
castType = Type::UByteTy;
|
|
break;
|
|
case 2:
|
|
castType = Type::UShortTy;
|
|
fill_value |= fill_char << 8;
|
|
break;
|
|
case 4:
|
|
castType = Type::UIntTy;
|
|
fill_value |= fill_char << 8 | fill_char << 16 | fill_char << 24;
|
|
break;
|
|
case 8:
|
|
castType = Type::ULongTy;
|
|
fill_value |= fill_char << 8 | fill_char << 16 | fill_char << 24;
|
|
fill_value |= fill_char << 32 | fill_char << 40 | fill_char << 48;
|
|
fill_value |= fill_char << 56;
|
|
break;
|
|
default:
|
|
return false;
|
|
}
|
|
|
|
// Cast dest to the right sized primitive and then load/store
|
|
CastInst* DestCast =
|
|
new CastInst(dest,PointerType::get(castType),dest->getName()+".cast",ci);
|
|
new StoreInst(ConstantUInt::get(castType,fill_value),DestCast, ci);
|
|
ci->eraseFromParent();
|
|
return true;
|
|
}
|
|
} LLVMMemSetOptimizer;
|
|
|
|
/// This LibCallOptimization will simplify calls to the "pow" library
|
|
/// function. It looks for cases where the result of pow is well known and
|
|
/// substitutes the appropriate value.
|
|
/// @brief Simplify the pow library function.
|
|
struct PowOptimization : public LibCallOptimization
|
|
{
|
|
public:
|
|
/// @brief Default Constructor
|
|
PowOptimization() : LibCallOptimization("pow",
|
|
"Number of 'pow' calls simplified") {}
|
|
|
|
/// @brief Destructor
|
|
virtual ~PowOptimization() {}
|
|
|
|
/// @brief Make sure that the "pow" function has the right prototype
|
|
virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC)
|
|
{
|
|
// Just make sure this has 2 arguments
|
|
return (f->arg_size() == 2);
|
|
}
|
|
|
|
/// @brief Perform the pow optimization.
|
|
virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& SLC)
|
|
{
|
|
const Type *Ty = cast<Function>(ci->getOperand(0))->getReturnType();
|
|
Value* base = ci->getOperand(1);
|
|
Value* expn = ci->getOperand(2);
|
|
if (ConstantFP *Op1 = dyn_cast<ConstantFP>(base)) {
|
|
double Op1V = Op1->getValue();
|
|
if (Op1V == 1.0)
|
|
{
|
|
// pow(1.0,x) -> 1.0
|
|
ci->replaceAllUsesWith(ConstantFP::get(Ty,1.0));
|
|
ci->eraseFromParent();
|
|
return true;
|
|
}
|
|
}
|
|
else if (ConstantFP* Op2 = dyn_cast<ConstantFP>(expn))
|
|
{
|
|
double Op2V = Op2->getValue();
|
|
if (Op2V == 0.0)
|
|
{
|
|
// pow(x,0.0) -> 1.0
|
|
ci->replaceAllUsesWith(ConstantFP::get(Ty,1.0));
|
|
ci->eraseFromParent();
|
|
return true;
|
|
}
|
|
else if (Op2V == 0.5)
|
|
{
|
|
// pow(x,0.5) -> sqrt(x)
|
|
CallInst* sqrt_inst = new CallInst(SLC.get_sqrt(), base,
|
|
ci->getName()+".pow",ci);
|
|
ci->replaceAllUsesWith(sqrt_inst);
|
|
ci->eraseFromParent();
|
|
return true;
|
|
}
|
|
else if (Op2V == 1.0)
|
|
{
|
|
// pow(x,1.0) -> x
|
|
ci->replaceAllUsesWith(base);
|
|
ci->eraseFromParent();
|
|
return true;
|
|
}
|
|
else if (Op2V == -1.0)
|
|
{
|
|
// pow(x,-1.0) -> 1.0/x
|
|
BinaryOperator* div_inst= BinaryOperator::createDiv(
|
|
ConstantFP::get(Ty,1.0), base, ci->getName()+".pow", ci);
|
|
ci->replaceAllUsesWith(div_inst);
|
|
ci->eraseFromParent();
|
|
return true;
|
|
}
|
|
}
|
|
return false; // opt failed
|
|
}
|
|
} PowOptimizer;
|
|
|
|
/// This LibCallOptimization will simplify calls to the "fprintf" library
|
|
/// function. It looks for cases where the result of fprintf is not used and the
|
|
/// operation can be reduced to something simpler.
|
|
/// @brief Simplify the pow library function.
|
|
struct FPrintFOptimization : public LibCallOptimization
|
|
{
|
|
public:
|
|
/// @brief Default Constructor
|
|
FPrintFOptimization() : LibCallOptimization("fprintf",
|
|
"Number of 'fprintf' calls simplified") {}
|
|
|
|
/// @brief Destructor
|
|
virtual ~FPrintFOptimization() {}
|
|
|
|
/// @brief Make sure that the "fprintf" function has the right prototype
|
|
virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC)
|
|
{
|
|
// Just make sure this has at least 2 arguments
|
|
return (f->arg_size() >= 2);
|
|
}
|
|
|
|
/// @brief Perform the fprintf optimization.
|
|
virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& SLC)
|
|
{
|
|
// If the call has more than 3 operands, we can't optimize it
|
|
if (ci->getNumOperands() > 4 || ci->getNumOperands() <= 2)
|
|
return false;
|
|
|
|
// If the result of the fprintf call is used, none of these optimizations
|
|
// can be made.
|
|
if (!ci->use_empty())
|
|
return false;
|
|
|
|
// All the optimizations depend on the length of the second argument and the
|
|
// fact that it is a constant string array. Check that now
|
|
uint64_t len = 0;
|
|
ConstantArray* CA = 0;
|
|
if (!getConstantStringLength(ci->getOperand(2), len, &CA))
|
|
return false;
|
|
|
|
if (ci->getNumOperands() == 3)
|
|
{
|
|
// Make sure there's no % in the constant array
|
|
for (unsigned i = 0; i < len; ++i)
|
|
{
|
|
if (ConstantInt* CI = dyn_cast<ConstantInt>(CA->getOperand(i)))
|
|
{
|
|
// Check for the null terminator
|
|
if (CI->getRawValue() == '%')
|
|
return false; // we found end of string
|
|
}
|
|
else
|
|
return false;
|
|
}
|
|
|
|
// fprintf(file,fmt) -> fwrite(fmt,strlen(fmt),file)
|
|
const Type* FILEptr_type = ci->getOperand(1)->getType();
|
|
Function* fwrite_func = SLC.get_fwrite(FILEptr_type);
|
|
if (!fwrite_func)
|
|
return false;
|
|
|
|
// Make sure that the fprintf() and fwrite() functions both take the
|
|
// same type of char pointer.
|
|
if (ci->getOperand(2)->getType() !=
|
|
fwrite_func->getFunctionType()->getParamType(0))
|
|
return false;
|
|
|
|
std::vector<Value*> args;
|
|
args.push_back(ci->getOperand(2));
|
|
args.push_back(ConstantUInt::get(SLC.getIntPtrType(),len));
|
|
args.push_back(ConstantUInt::get(SLC.getIntPtrType(),1));
|
|
args.push_back(ci->getOperand(1));
|
|
new CallInst(fwrite_func,args,ci->getName(),ci);
|
|
ci->replaceAllUsesWith(ConstantSInt::get(Type::IntTy,len));
|
|
ci->eraseFromParent();
|
|
return true;
|
|
}
|
|
|
|
// The remaining optimizations require the format string to be length 2
|
|
// "%s" or "%c".
|
|
if (len != 2)
|
|
return false;
|
|
|
|
// The first character has to be a %
|
|
if (ConstantInt* CI = dyn_cast<ConstantInt>(CA->getOperand(0)))
|
|
if (CI->getRawValue() != '%')
|
|
return false;
|
|
|
|
// Get the second character and switch on its value
|
|
ConstantInt* CI = dyn_cast<ConstantInt>(CA->getOperand(1));
|
|
switch (CI->getRawValue())
|
|
{
|
|
case 's':
|
|
{
|
|
uint64_t len = 0;
|
|
ConstantArray* CA = 0;
|
|
if (!getConstantStringLength(ci->getOperand(3), len, &CA))
|
|
return false;
|
|
|
|
// fprintf(file,"%s",str) -> fwrite(fmt,strlen(fmt),1,file)
|
|
const Type* FILEptr_type = ci->getOperand(1)->getType();
|
|
Function* fwrite_func = SLC.get_fwrite(FILEptr_type);
|
|
if (!fwrite_func)
|
|
return false;
|
|
std::vector<Value*> args;
|
|
args.push_back(CastToCStr(ci->getOperand(3), *ci));
|
|
args.push_back(ConstantUInt::get(SLC.getIntPtrType(),len));
|
|
args.push_back(ConstantUInt::get(SLC.getIntPtrType(),1));
|
|
args.push_back(ci->getOperand(1));
|
|
new CallInst(fwrite_func,args,ci->getName(),ci);
|
|
ci->replaceAllUsesWith(ConstantSInt::get(Type::IntTy,len));
|
|
break;
|
|
}
|
|
case 'c':
|
|
{
|
|
ConstantInt* CI = dyn_cast<ConstantInt>(ci->getOperand(3));
|
|
if (!CI)
|
|
return false;
|
|
|
|
const Type* FILEptr_type = ci->getOperand(1)->getType();
|
|
Function* fputc_func = SLC.get_fputc(FILEptr_type);
|
|
if (!fputc_func)
|
|
return false;
|
|
CastInst* cast = new CastInst(CI,Type::IntTy,CI->getName()+".int",ci);
|
|
new CallInst(fputc_func,cast,ci->getOperand(1),"",ci);
|
|
ci->replaceAllUsesWith(ConstantSInt::get(Type::IntTy,1));
|
|
break;
|
|
}
|
|
default:
|
|
return false;
|
|
}
|
|
ci->eraseFromParent();
|
|
return true;
|
|
}
|
|
} FPrintFOptimizer;
|
|
|
|
/// This LibCallOptimization will simplify calls to the "sprintf" library
|
|
/// function. It looks for cases where the result of sprintf is not used and the
|
|
/// operation can be reduced to something simpler.
|
|
/// @brief Simplify the pow library function.
|
|
struct SPrintFOptimization : public LibCallOptimization
|
|
{
|
|
public:
|
|
/// @brief Default Constructor
|
|
SPrintFOptimization() : LibCallOptimization("sprintf",
|
|
"Number of 'sprintf' calls simplified") {}
|
|
|
|
/// @brief Destructor
|
|
virtual ~SPrintFOptimization() {}
|
|
|
|
/// @brief Make sure that the "fprintf" function has the right prototype
|
|
virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC)
|
|
{
|
|
// Just make sure this has at least 2 arguments
|
|
return (f->getReturnType() == Type::IntTy && f->arg_size() >= 2);
|
|
}
|
|
|
|
/// @brief Perform the sprintf optimization.
|
|
virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& SLC)
|
|
{
|
|
// If the call has more than 3 operands, we can't optimize it
|
|
if (ci->getNumOperands() > 4 || ci->getNumOperands() < 3)
|
|
return false;
|
|
|
|
// All the optimizations depend on the length of the second argument and the
|
|
// fact that it is a constant string array. Check that now
|
|
uint64_t len = 0;
|
|
ConstantArray* CA = 0;
|
|
if (!getConstantStringLength(ci->getOperand(2), len, &CA))
|
|
return false;
|
|
|
|
if (ci->getNumOperands() == 3)
|
|
{
|
|
if (len == 0)
|
|
{
|
|
// If the length is 0, we just need to store a null byte
|
|
new StoreInst(ConstantInt::get(Type::SByteTy,0),ci->getOperand(1),ci);
|
|
ci->replaceAllUsesWith(ConstantSInt::get(Type::IntTy,0));
|
|
ci->eraseFromParent();
|
|
return true;
|
|
}
|
|
|
|
// Make sure there's no % in the constant array
|
|
for (unsigned i = 0; i < len; ++i)
|
|
{
|
|
if (ConstantInt* CI = dyn_cast<ConstantInt>(CA->getOperand(i)))
|
|
{
|
|
// Check for the null terminator
|
|
if (CI->getRawValue() == '%')
|
|
return false; // we found a %, can't optimize
|
|
}
|
|
else
|
|
return false; // initializer is not constant int, can't optimize
|
|
}
|
|
|
|
// Increment length because we want to copy the null byte too
|
|
len++;
|
|
|
|
// sprintf(str,fmt) -> llvm.memcpy(str,fmt,strlen(fmt),1)
|
|
Function* memcpy_func = SLC.get_memcpy();
|
|
if (!memcpy_func)
|
|
return false;
|
|
std::vector<Value*> args;
|
|
args.push_back(ci->getOperand(1));
|
|
args.push_back(ci->getOperand(2));
|
|
args.push_back(ConstantUInt::get(Type::UIntTy,len));
|
|
args.push_back(ConstantUInt::get(Type::UIntTy,1));
|
|
new CallInst(memcpy_func,args,"",ci);
|
|
ci->replaceAllUsesWith(ConstantSInt::get(Type::IntTy,len));
|
|
ci->eraseFromParent();
|
|
return true;
|
|
}
|
|
|
|
// The remaining optimizations require the format string to be length 2
|
|
// "%s" or "%c".
|
|
if (len != 2)
|
|
return false;
|
|
|
|
// The first character has to be a %
|
|
if (ConstantInt* CI = dyn_cast<ConstantInt>(CA->getOperand(0)))
|
|
if (CI->getRawValue() != '%')
|
|
return false;
|
|
|
|
// Get the second character and switch on its value
|
|
ConstantInt* CI = dyn_cast<ConstantInt>(CA->getOperand(1));
|
|
switch (CI->getRawValue()) {
|
|
case 's': {
|
|
// sprintf(dest,"%s",str) -> llvm.memcpy(dest, str, strlen(str)+1, 1)
|
|
Function* strlen_func = SLC.get_strlen();
|
|
Function* memcpy_func = SLC.get_memcpy();
|
|
if (!strlen_func || !memcpy_func)
|
|
return false;
|
|
|
|
Value *Len = new CallInst(strlen_func, CastToCStr(ci->getOperand(3), *ci),
|
|
ci->getOperand(3)->getName()+".len", ci);
|
|
Value *Len1 = BinaryOperator::createAdd(Len,
|
|
ConstantInt::get(Len->getType(), 1),
|
|
Len->getName()+"1", ci);
|
|
if (Len1->getType() != Type::UIntTy)
|
|
Len1 = new CastInst(Len1, Type::UIntTy, Len1->getName(), ci);
|
|
std::vector<Value*> args;
|
|
args.push_back(CastToCStr(ci->getOperand(1), *ci));
|
|
args.push_back(CastToCStr(ci->getOperand(3), *ci));
|
|
args.push_back(Len1);
|
|
args.push_back(ConstantUInt::get(Type::UIntTy,1));
|
|
new CallInst(memcpy_func, args, "", ci);
|
|
|
|
// The strlen result is the unincremented number of bytes in the string.
|
|
if (!ci->use_empty()) {
|
|
if (Len->getType() != ci->getType())
|
|
Len = new CastInst(Len, ci->getType(), Len->getName(), ci);
|
|
ci->replaceAllUsesWith(Len);
|
|
}
|
|
ci->eraseFromParent();
|
|
return true;
|
|
}
|
|
case 'c': {
|
|
// sprintf(dest,"%c",chr) -> store chr, dest
|
|
CastInst* cast = new CastInst(ci->getOperand(3),Type::SByteTy,"char",ci);
|
|
new StoreInst(cast, ci->getOperand(1), ci);
|
|
GetElementPtrInst* gep = new GetElementPtrInst(ci->getOperand(1),
|
|
ConstantUInt::get(Type::UIntTy,1),ci->getOperand(1)->getName()+".end",
|
|
ci);
|
|
new StoreInst(ConstantInt::get(Type::SByteTy,0),gep,ci);
|
|
ci->replaceAllUsesWith(ConstantSInt::get(Type::IntTy,1));
|
|
ci->eraseFromParent();
|
|
return true;
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
} SPrintFOptimizer;
|
|
|
|
/// This LibCallOptimization will simplify calls to the "fputs" library
|
|
/// function. It looks for cases where the result of fputs is not used and the
|
|
/// operation can be reduced to something simpler.
|
|
/// @brief Simplify the pow library function.
|
|
struct PutsOptimization : public LibCallOptimization
|
|
{
|
|
public:
|
|
/// @brief Default Constructor
|
|
PutsOptimization() : LibCallOptimization("fputs",
|
|
"Number of 'fputs' calls simplified") {}
|
|
|
|
/// @brief Destructor
|
|
virtual ~PutsOptimization() {}
|
|
|
|
/// @brief Make sure that the "fputs" function has the right prototype
|
|
virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC)
|
|
{
|
|
// Just make sure this has 2 arguments
|
|
return (f->arg_size() == 2);
|
|
}
|
|
|
|
/// @brief Perform the fputs optimization.
|
|
virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& SLC)
|
|
{
|
|
// If the result is used, none of these optimizations work
|
|
if (!ci->use_empty())
|
|
return false;
|
|
|
|
// All the optimizations depend on the length of the first argument and the
|
|
// fact that it is a constant string array. Check that now
|
|
uint64_t len = 0;
|
|
if (!getConstantStringLength(ci->getOperand(1), len))
|
|
return false;
|
|
|
|
switch (len)
|
|
{
|
|
case 0:
|
|
// fputs("",F) -> noop
|
|
break;
|
|
case 1:
|
|
{
|
|
// fputs(s,F) -> fputc(s[0],F) (if s is constant and strlen(s) == 1)
|
|
const Type* FILEptr_type = ci->getOperand(2)->getType();
|
|
Function* fputc_func = SLC.get_fputc(FILEptr_type);
|
|
if (!fputc_func)
|
|
return false;
|
|
LoadInst* loadi = new LoadInst(ci->getOperand(1),
|
|
ci->getOperand(1)->getName()+".byte",ci);
|
|
CastInst* casti = new CastInst(loadi,Type::IntTy,
|
|
loadi->getName()+".int",ci);
|
|
new CallInst(fputc_func,casti,ci->getOperand(2),"",ci);
|
|
break;
|
|
}
|
|
default:
|
|
{
|
|
// fputs(s,F) -> fwrite(s,1,len,F) (if s is constant and strlen(s) > 1)
|
|
const Type* FILEptr_type = ci->getOperand(2)->getType();
|
|
Function* fwrite_func = SLC.get_fwrite(FILEptr_type);
|
|
if (!fwrite_func)
|
|
return false;
|
|
std::vector<Value*> parms;
|
|
parms.push_back(ci->getOperand(1));
|
|
parms.push_back(ConstantUInt::get(SLC.getIntPtrType(),len));
|
|
parms.push_back(ConstantUInt::get(SLC.getIntPtrType(),1));
|
|
parms.push_back(ci->getOperand(2));
|
|
new CallInst(fwrite_func,parms,"",ci);
|
|
break;
|
|
}
|
|
}
|
|
ci->eraseFromParent();
|
|
return true; // success
|
|
}
|
|
} PutsOptimizer;
|
|
|
|
/// This LibCallOptimization will simplify calls to the "isdigit" library
|
|
/// function. It simply does range checks the parameter explicitly.
|
|
/// @brief Simplify the isdigit library function.
|
|
struct IsDigitOptimization : public LibCallOptimization
|
|
{
|
|
public:
|
|
/// @brief Default Constructor
|
|
IsDigitOptimization() : LibCallOptimization("isdigit",
|
|
"Number of 'isdigit' calls simplified") {}
|
|
|
|
/// @brief Destructor
|
|
virtual ~IsDigitOptimization() {}
|
|
|
|
/// @brief Make sure that the "fputs" function has the right prototype
|
|
virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC)
|
|
{
|
|
// Just make sure this has 1 argument
|
|
return (f->arg_size() == 1);
|
|
}
|
|
|
|
/// @brief Perform the toascii optimization.
|
|
virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& SLC)
|
|
{
|
|
if (ConstantInt* CI = dyn_cast<ConstantInt>(ci->getOperand(1)))
|
|
{
|
|
// isdigit(c) -> 0 or 1, if 'c' is constant
|
|
uint64_t val = CI->getRawValue();
|
|
if (val >= '0' && val <='9')
|
|
ci->replaceAllUsesWith(ConstantSInt::get(Type::IntTy,1));
|
|
else
|
|
ci->replaceAllUsesWith(ConstantSInt::get(Type::IntTy,0));
|
|
ci->eraseFromParent();
|
|
return true;
|
|
}
|
|
|
|
// isdigit(c) -> (unsigned)c - '0' <= 9
|
|
CastInst* cast =
|
|
new CastInst(ci->getOperand(1),Type::UIntTy,
|
|
ci->getOperand(1)->getName()+".uint",ci);
|
|
BinaryOperator* sub_inst = BinaryOperator::createSub(cast,
|
|
ConstantUInt::get(Type::UIntTy,0x30),
|
|
ci->getOperand(1)->getName()+".sub",ci);
|
|
SetCondInst* setcond_inst = new SetCondInst(Instruction::SetLE,sub_inst,
|
|
ConstantUInt::get(Type::UIntTy,9),
|
|
ci->getOperand(1)->getName()+".cmp",ci);
|
|
CastInst* c2 =
|
|
new CastInst(setcond_inst,Type::IntTy,
|
|
ci->getOperand(1)->getName()+".isdigit",ci);
|
|
ci->replaceAllUsesWith(c2);
|
|
ci->eraseFromParent();
|
|
return true;
|
|
}
|
|
} IsDigitOptimizer;
|
|
|
|
/// This LibCallOptimization will simplify calls to the "toascii" library
|
|
/// function. It simply does the corresponding and operation to restrict the
|
|
/// range of values to the ASCII character set (0-127).
|
|
/// @brief Simplify the toascii library function.
|
|
struct ToAsciiOptimization : public LibCallOptimization
|
|
{
|
|
public:
|
|
/// @brief Default Constructor
|
|
ToAsciiOptimization() : LibCallOptimization("toascii",
|
|
"Number of 'toascii' calls simplified") {}
|
|
|
|
/// @brief Destructor
|
|
virtual ~ToAsciiOptimization() {}
|
|
|
|
/// @brief Make sure that the "fputs" function has the right prototype
|
|
virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC)
|
|
{
|
|
// Just make sure this has 2 arguments
|
|
return (f->arg_size() == 1);
|
|
}
|
|
|
|
/// @brief Perform the toascii optimization.
|
|
virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& SLC)
|
|
{
|
|
// toascii(c) -> (c & 0x7f)
|
|
Value* chr = ci->getOperand(1);
|
|
BinaryOperator* and_inst = BinaryOperator::createAnd(chr,
|
|
ConstantInt::get(chr->getType(),0x7F),ci->getName()+".toascii",ci);
|
|
ci->replaceAllUsesWith(and_inst);
|
|
ci->eraseFromParent();
|
|
return true;
|
|
}
|
|
} ToAsciiOptimizer;
|
|
|
|
/// This LibCallOptimization will simplify calls to the "ffs" library
|
|
/// calls which find the first set bit in an int, long, or long long. The
|
|
/// optimization is to compute the result at compile time if the argument is
|
|
/// a constant.
|
|
/// @brief Simplify the ffs library function.
|
|
struct FFSOptimization : public LibCallOptimization
|
|
{
|
|
protected:
|
|
/// @brief Subclass Constructor
|
|
FFSOptimization(const char* funcName, const char* description)
|
|
: LibCallOptimization(funcName, description)
|
|
{}
|
|
|
|
public:
|
|
/// @brief Default Constructor
|
|
FFSOptimization() : LibCallOptimization("ffs",
|
|
"Number of 'ffs' calls simplified") {}
|
|
|
|
/// @brief Destructor
|
|
virtual ~FFSOptimization() {}
|
|
|
|
/// @brief Make sure that the "fputs" function has the right prototype
|
|
virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC)
|
|
{
|
|
// Just make sure this has 2 arguments
|
|
return (f->arg_size() == 1 && f->getReturnType() == Type::IntTy);
|
|
}
|
|
|
|
/// @brief Perform the ffs optimization.
|
|
virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& SLC)
|
|
{
|
|
if (ConstantInt* CI = dyn_cast<ConstantInt>(ci->getOperand(1)))
|
|
{
|
|
// ffs(cnst) -> bit#
|
|
// ffsl(cnst) -> bit#
|
|
// ffsll(cnst) -> bit#
|
|
uint64_t val = CI->getRawValue();
|
|
int result = 0;
|
|
while (val != 0) {
|
|
result +=1;
|
|
if (val&1)
|
|
break;
|
|
val >>= 1;
|
|
}
|
|
ci->replaceAllUsesWith(ConstantSInt::get(Type::IntTy, result));
|
|
ci->eraseFromParent();
|
|
return true;
|
|
}
|
|
|
|
// ffs(x) -> ( x == 0 ? 0 : llvm.cttz(x)+1)
|
|
// ffsl(x) -> ( x == 0 ? 0 : llvm.cttz(x)+1)
|
|
// ffsll(x) -> ( x == 0 ? 0 : llvm.cttz(x)+1)
|
|
const Type* arg_type = ci->getOperand(1)->getType();
|
|
std::vector<const Type*> args;
|
|
args.push_back(arg_type);
|
|
FunctionType* llvm_cttz_type = FunctionType::get(arg_type,args,false);
|
|
Function* F =
|
|
SLC.getModule()->getOrInsertFunction("llvm.cttz",llvm_cttz_type);
|
|
std::string inst_name(ci->getName()+".ffs");
|
|
Instruction* call =
|
|
new CallInst(F, ci->getOperand(1), inst_name, ci);
|
|
if (arg_type != Type::IntTy)
|
|
call = new CastInst(call, Type::IntTy, inst_name, ci);
|
|
BinaryOperator* add = BinaryOperator::createAdd(call,
|
|
ConstantSInt::get(Type::IntTy,1), inst_name, ci);
|
|
SetCondInst* eq = new SetCondInst(Instruction::SetEQ,ci->getOperand(1),
|
|
ConstantSInt::get(ci->getOperand(1)->getType(),0),inst_name,ci);
|
|
SelectInst* select = new SelectInst(eq,ConstantSInt::get(Type::IntTy,0),add,
|
|
inst_name,ci);
|
|
ci->replaceAllUsesWith(select);
|
|
ci->eraseFromParent();
|
|
return true;
|
|
}
|
|
} FFSOptimizer;
|
|
|
|
/// This LibCallOptimization will simplify calls to the "ffsl" library
|
|
/// calls. It simply uses FFSOptimization for which the transformation is
|
|
/// identical.
|
|
/// @brief Simplify the ffsl library function.
|
|
struct FFSLOptimization : public FFSOptimization
|
|
{
|
|
public:
|
|
/// @brief Default Constructor
|
|
FFSLOptimization() : FFSOptimization("ffsl",
|
|
"Number of 'ffsl' calls simplified") {}
|
|
|
|
} FFSLOptimizer;
|
|
|
|
/// This LibCallOptimization will simplify calls to the "ffsll" library
|
|
/// calls. It simply uses FFSOptimization for which the transformation is
|
|
/// identical.
|
|
/// @brief Simplify the ffsl library function.
|
|
struct FFSLLOptimization : public FFSOptimization
|
|
{
|
|
public:
|
|
/// @brief Default Constructor
|
|
FFSLLOptimization() : FFSOptimization("ffsll",
|
|
"Number of 'ffsll' calls simplified") {}
|
|
|
|
} FFSLLOptimizer;
|
|
|
|
|
|
/// This LibCallOptimization will simplify calls to the "floor" library
|
|
/// function.
|
|
/// @brief Simplify the floor library function.
|
|
struct FloorOptimization : public LibCallOptimization {
|
|
FloorOptimization()
|
|
: LibCallOptimization("floor", "Number of 'floor' calls simplified") {}
|
|
|
|
/// @brief Make sure that the "floor" function has the right prototype
|
|
virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
|
|
return F->arg_size() == 1 && F->arg_begin()->getType() == Type::DoubleTy &&
|
|
F->getReturnType() == Type::DoubleTy;
|
|
}
|
|
|
|
virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
|
|
// If this is a float argument passed in, convert to floorf.
|
|
// e.g. floor((double)FLT) -> (double)floorf(FLT). There can be no loss of
|
|
// precision due to this.
|
|
if (CastInst *Cast = dyn_cast<CastInst>(CI->getOperand(1)))
|
|
if (Cast->getOperand(0)->getType() == Type::FloatTy) {
|
|
Value *New = new CallInst(SLC.get_floorf(), Cast->getOperand(0),
|
|
CI->getName(), CI);
|
|
New = new CastInst(New, Type::DoubleTy, CI->getName(), CI);
|
|
CI->replaceAllUsesWith(New);
|
|
CI->eraseFromParent();
|
|
if (Cast->use_empty())
|
|
Cast->eraseFromParent();
|
|
return true;
|
|
}
|
|
return false; // opt failed
|
|
}
|
|
} FloorOptimizer;
|
|
|
|
|
|
|
|
/// A function to compute the length of a null-terminated constant array of
|
|
/// integers. This function can't rely on the size of the constant array
|
|
/// because there could be a null terminator in the middle of the array.
|
|
/// We also have to bail out if we find a non-integer constant initializer
|
|
/// of one of the elements or if there is no null-terminator. The logic
|
|
/// below checks each of these conditions and will return true only if all
|
|
/// conditions are met. In that case, the \p len parameter is set to the length
|
|
/// of the null-terminated string. If false is returned, the conditions were
|
|
/// not met and len is set to 0.
|
|
/// @brief Get the length of a constant string (null-terminated array).
|
|
bool getConstantStringLength(Value* V, uint64_t& len, ConstantArray** CA )
|
|
{
|
|
assert(V != 0 && "Invalid args to getConstantStringLength");
|
|
len = 0; // make sure we initialize this
|
|
User* GEP = 0;
|
|
// If the value is not a GEP instruction nor a constant expression with a
|
|
// GEP instruction, then return false because ConstantArray can't occur
|
|
// any other way
|
|
if (GetElementPtrInst* GEPI = dyn_cast<GetElementPtrInst>(V))
|
|
GEP = GEPI;
|
|
else if (ConstantExpr* CE = dyn_cast<ConstantExpr>(V))
|
|
if (CE->getOpcode() == Instruction::GetElementPtr)
|
|
GEP = CE;
|
|
else
|
|
return false;
|
|
else
|
|
return false;
|
|
|
|
// Make sure the GEP has exactly three arguments.
|
|
if (GEP->getNumOperands() != 3)
|
|
return false;
|
|
|
|
// Check to make sure that the first operand of the GEP is an integer and
|
|
// has value 0 so that we are sure we're indexing into the initializer.
|
|
if (ConstantInt* op1 = dyn_cast<ConstantInt>(GEP->getOperand(1)))
|
|
{
|
|
if (!op1->isNullValue())
|
|
return false;
|
|
}
|
|
else
|
|
return false;
|
|
|
|
// Ensure that the second operand is a ConstantInt. If it isn't then this
|
|
// GEP is wonky and we're not really sure what were referencing into and
|
|
// better of not optimizing it. While we're at it, get the second index
|
|
// value. We'll need this later for indexing the ConstantArray.
|
|
uint64_t start_idx = 0;
|
|
if (ConstantInt* CI = dyn_cast<ConstantInt>(GEP->getOperand(2)))
|
|
start_idx = CI->getRawValue();
|
|
else
|
|
return false;
|
|
|
|
// The GEP instruction, constant or instruction, must reference a global
|
|
// variable that is a constant and is initialized. The referenced constant
|
|
// initializer is the array that we'll use for optimization.
|
|
GlobalVariable* GV = dyn_cast<GlobalVariable>(GEP->getOperand(0));
|
|
if (!GV || !GV->isConstant() || !GV->hasInitializer())
|
|
return false;
|
|
|
|
// Get the initializer.
|
|
Constant* INTLZR = GV->getInitializer();
|
|
|
|
// Handle the ConstantAggregateZero case
|
|
if (ConstantAggregateZero* CAZ = dyn_cast<ConstantAggregateZero>(INTLZR))
|
|
{
|
|
// This is a degenerate case. The initializer is constant zero so the
|
|
// length of the string must be zero.
|
|
len = 0;
|
|
return true;
|
|
}
|
|
|
|
// Must be a Constant Array
|
|
ConstantArray* A = dyn_cast<ConstantArray>(INTLZR);
|
|
if (!A)
|
|
return false;
|
|
|
|
// Get the number of elements in the array
|
|
uint64_t max_elems = A->getType()->getNumElements();
|
|
|
|
// Traverse the constant array from start_idx (derived above) which is
|
|
// the place the GEP refers to in the array.
|
|
for ( len = start_idx; len < max_elems; len++)
|
|
{
|
|
if (ConstantInt* CI = dyn_cast<ConstantInt>(A->getOperand(len)))
|
|
{
|
|
// Check for the null terminator
|
|
if (CI->isNullValue())
|
|
break; // we found end of string
|
|
}
|
|
else
|
|
return false; // This array isn't suitable, non-int initializer
|
|
}
|
|
if (len >= max_elems)
|
|
return false; // This array isn't null terminated
|
|
|
|
// Subtract out the initial value from the length
|
|
len -= start_idx;
|
|
if (CA)
|
|
*CA = A;
|
|
return true; // success!
|
|
}
|
|
|
|
/// CastToCStr - Return V if it is an sbyte*, otherwise cast it to sbyte*,
|
|
/// inserting the cast before IP, and return the cast.
|
|
/// @brief Cast a value to a "C" string.
|
|
Value *CastToCStr(Value *V, Instruction &IP) {
|
|
const Type *SBPTy = PointerType::get(Type::SByteTy);
|
|
if (V->getType() != SBPTy)
|
|
return new CastInst(V, SBPTy, V->getName(), &IP);
|
|
return V;
|
|
}
|
|
|
|
// TODO:
|
|
// Additional cases that we need to add to this file:
|
|
//
|
|
// cbrt:
|
|
// * cbrt(expN(X)) -> expN(x/3)
|
|
// * cbrt(sqrt(x)) -> pow(x,1/6)
|
|
// * cbrt(sqrt(x)) -> pow(x,1/9)
|
|
//
|
|
// cos, cosf, cosl:
|
|
// * cos(-x) -> cos(x)
|
|
//
|
|
// exp, expf, expl:
|
|
// * exp(log(x)) -> x
|
|
//
|
|
// isascii:
|
|
// * isascii(c) -> ((c & ~0x7f) == 0)
|
|
//
|
|
// isdigit:
|
|
// * isdigit(c) -> (unsigned)(c) - '0' <= 9
|
|
//
|
|
// log, logf, logl:
|
|
// * log(exp(x)) -> x
|
|
// * log(x**y) -> y*log(x)
|
|
// * log(exp(y)) -> y*log(e)
|
|
// * log(exp2(y)) -> y*log(2)
|
|
// * log(exp10(y)) -> y*log(10)
|
|
// * log(sqrt(x)) -> 0.5*log(x)
|
|
// * log(pow(x,y)) -> y*log(x)
|
|
//
|
|
// lround, lroundf, lroundl:
|
|
// * lround(cnst) -> cnst'
|
|
//
|
|
// memcmp:
|
|
// * memcmp(s1,s2,0) -> 0
|
|
// * memcmp(x,x,l) -> 0
|
|
// * memcmp(x,y,l) -> cnst
|
|
// (if all arguments are constant and strlen(x) <= l and strlen(y) <= l)
|
|
// * memcmp(x,y,1) -> *x - *y
|
|
//
|
|
// memmove:
|
|
// * memmove(d,s,l,a) -> memcpy(d,s,l,a)
|
|
// (if s is a global constant array)
|
|
//
|
|
// pow, powf, powl:
|
|
// * pow(exp(x),y) -> exp(x*y)
|
|
// * pow(sqrt(x),y) -> pow(x,y*0.5)
|
|
// * pow(pow(x,y),z)-> pow(x,y*z)
|
|
//
|
|
// puts:
|
|
// * puts("") -> fputc("\n",stdout) (how do we get "stdout"?)
|
|
//
|
|
// round, roundf, roundl:
|
|
// * round(cnst) -> cnst'
|
|
//
|
|
// signbit:
|
|
// * signbit(cnst) -> cnst'
|
|
// * signbit(nncst) -> 0 (if pstv is a non-negative constant)
|
|
//
|
|
// sqrt, sqrtf, sqrtl:
|
|
// * sqrt(expN(x)) -> expN(x*0.5)
|
|
// * sqrt(Nroot(x)) -> pow(x,1/(2*N))
|
|
// * sqrt(pow(x,y)) -> pow(|x|,y*0.5)
|
|
//
|
|
// stpcpy:
|
|
// * stpcpy(str, "literal") ->
|
|
// llvm.memcpy(str,"literal",strlen("literal")+1,1)
|
|
// strrchr:
|
|
// * strrchr(s,c) -> reverse_offset_of_in(c,s)
|
|
// (if c is a constant integer and s is a constant string)
|
|
// * strrchr(s1,0) -> strchr(s1,0)
|
|
//
|
|
// strncat:
|
|
// * strncat(x,y,0) -> x
|
|
// * strncat(x,y,0) -> x (if strlen(y) = 0)
|
|
// * strncat(x,y,l) -> strcat(x,y) (if y and l are constants an l > strlen(y))
|
|
//
|
|
// strncpy:
|
|
// * strncpy(d,s,0) -> d
|
|
// * strncpy(d,s,l) -> memcpy(d,s,l,1)
|
|
// (if s and l are constants)
|
|
//
|
|
// strpbrk:
|
|
// * strpbrk(s,a) -> offset_in_for(s,a)
|
|
// (if s and a are both constant strings)
|
|
// * strpbrk(s,"") -> 0
|
|
// * strpbrk(s,a) -> strchr(s,a[0]) (if a is constant string of length 1)
|
|
//
|
|
// strspn, strcspn:
|
|
// * strspn(s,a) -> const_int (if both args are constant)
|
|
// * strspn("",a) -> 0
|
|
// * strspn(s,"") -> 0
|
|
// * strcspn(s,a) -> const_int (if both args are constant)
|
|
// * strcspn("",a) -> 0
|
|
// * strcspn(s,"") -> strlen(a)
|
|
//
|
|
// strstr:
|
|
// * strstr(x,x) -> x
|
|
// * strstr(s1,s2) -> offset_of_s2_in(s1)
|
|
// (if s1 and s2 are constant strings)
|
|
//
|
|
// tan, tanf, tanl:
|
|
// * tan(atan(x)) -> x
|
|
//
|
|
// trunc, truncf, truncl:
|
|
// * trunc(cnst) -> cnst'
|
|
//
|
|
//
|
|
}
|