llvm-mirror/tools/opt/AnalysisWrappers.cpp
Chandler Carruth fad39ebe19 [C++11] Add range based accessors for the Use-Def chain of a Value.
This requires a number of steps.
1) Move value_use_iterator into the Value class as an implementation
   detail
2) Change it to actually be a *Use* iterator rather than a *User*
   iterator.
3) Add an adaptor which is a User iterator that always looks through the
   Use to the User.
4) Wrap these in Value::use_iterator and Value::user_iterator typedefs.
5) Add the range adaptors as Value::uses() and Value::users().
6) Update *all* of the callers to correctly distinguish between whether
   they wanted a use_iterator (and to explicitly dig out the User when
   needed), or a user_iterator which makes the Use itself totally
   opaque.

Because #6 requires churning essentially everything that walked the
Use-Def chains, I went ahead and added all of the range adaptors and
switched them to range-based loops where appropriate. Also because the
renaming requires at least churning every line of code, it didn't make
any sense to split these up into multiple commits -- all of which would
touch all of the same lies of code.

The result is still not quite optimal. The Value::use_iterator is a nice
regular iterator, but Value::user_iterator is an iterator over User*s
rather than over the User objects themselves. As a consequence, it fits
a bit awkwardly into the range-based world and it has the weird
extra-dereferencing 'operator->' that so many of our iterators have.
I think this could be fixed by providing something which transforms
a range of T&s into a range of T*s, but that *can* be separated into
another patch, and it isn't yet 100% clear whether this is the right
move.

However, this change gets us most of the benefit and cleans up
a substantial amount of code around Use and User. =]

llvm-svn: 203364
2014-03-09 03:16:01 +00:00

94 lines
3.1 KiB
C++

//===- AnalysisWrappers.cpp - Wrappers around non-pass analyses -----------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines pass wrappers around LLVM analyses that don't make sense to
// be passes. It provides a nice standard pass interface to these classes so
// that they can be printed out by analyze.
//
// These classes are separated out of analyze.cpp so that it is more clear which
// code is the integral part of the analyze tool, and which part of the code is
// just making it so more passes are available.
//
//===----------------------------------------------------------------------===//
#include "llvm/Analysis/CallGraph.h"
#include "llvm/IR/CallSite.h"
#include "llvm/IR/Module.h"
#include "llvm/Pass.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
namespace {
/// ExternalFunctionsPassedConstants - This pass prints out call sites to
/// external functions that are called with constant arguments. This can be
/// useful when looking for standard library functions we should constant fold
/// or handle in alias analyses.
struct ExternalFunctionsPassedConstants : public ModulePass {
static char ID; // Pass ID, replacement for typeid
ExternalFunctionsPassedConstants() : ModulePass(ID) {}
bool runOnModule(Module &M) override {
for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I) {
if (!I->isDeclaration()) continue;
bool PrintedFn = false;
for (User *U : I->users()) {
Instruction *UI = dyn_cast<Instruction>(U);
if (!UI) continue;
CallSite CS(cast<Value>(UI));
if (!CS) continue;
for (CallSite::arg_iterator AI = CS.arg_begin(),
E = CS.arg_end(); AI != E; ++AI) {
if (!isa<Constant>(*AI)) continue;
if (!PrintedFn) {
errs() << "Function '" << I->getName() << "':\n";
PrintedFn = true;
}
errs() << *UI;
break;
}
}
}
return false;
}
void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.setPreservesAll();
}
};
}
char ExternalFunctionsPassedConstants::ID = 0;
static RegisterPass<ExternalFunctionsPassedConstants>
P1("print-externalfnconstants",
"Print external fn callsites passed constants");
namespace {
struct CallGraphPrinter : public ModulePass {
static char ID; // Pass ID, replacement for typeid
CallGraphPrinter() : ModulePass(ID) {}
void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.setPreservesAll();
AU.addRequiredTransitive<CallGraphWrapperPass>();
}
bool runOnModule(Module &M) override {
getAnalysis<CallGraphWrapperPass>().print(errs(), &M);
return false;
}
};
}
char CallGraphPrinter::ID = 0;
static RegisterPass<CallGraphPrinter>
P2("print-callgraph", "Print a call graph");