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Make the FunctionComparator of the MergeFunctions pass a stand-alone utility.

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This is pure refactoring. NFC.

This change moves the FunctionComparator (together with the GlobalNumberState
utility) in to a separate file so that it can be used by other passes.
For example, the SwiftMergeFunctions pass in the Swift compiler:
https://github.com/apple/swift/blob/master/lib/LLVMPasses/LLVMMergeFunctions.cpp

Details of the change:

*) The big part is just moving code out of MergeFunctions.cpp into FunctionComparator.h/cpp
*) Make FunctionComparator member functions protected (instead of private)
   so that a derived comparator class can use them.

Following refactoring helps to share code between the base FunctionComparator
class and a derived class:

*) Add a beginCompare() function
*) Move some basic function property comparisons into a separate function compareSignature()
*) Do the GEP comparison inside cmpOperations() which now has a new
   needToCmpOperands reference parameter

https://reviews.llvm.org/D25385



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@286632 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Erik Eckstein 2016-11-11 21:15:13 +00:00
parent 6b8a0789f7
commit 345d21cba1
6 changed files with 1422 additions and 1217 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

367
include/llvm/Transforms/Utils/FunctionComparator.h Normal file
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//===- FunctionComparator.h - Function Comparator ---------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines the FunctionComparator and GlobalNumberState classes which
// are used by the MergeFunctions pass for comparing functions.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_TRANSFORMS_UTILS_FUNCTIONCOMPARATOR_H
#define LLVM_TRANSFORMS_UTILS_FUNCTIONCOMPARATOR_H
#include "llvm/IR/Function.h"
#include "llvm/IR/ValueMap.h"
#include "llvm/IR/Operator.h"
#include "llvm/Support/AtomicOrdering.h"
namespace llvm {
/// GlobalNumberState assigns an integer to each global value in the program,
/// which is used by the comparison routine to order references to globals. This
/// state must be preserved throughout the pass, because Functions and other
/// globals need to maintain their relative order. Globals are assigned a number
/// when they are first visited. This order is deterministic, and so the
/// assigned numbers are as well. When two functions are merged, neither number
/// is updated. If the symbols are weak, this would be incorrect. If they are
/// strong, then one will be replaced at all references to the other, and so
/// direct callsites will now see one or the other symbol, and no update is
/// necessary. Note that if we were guaranteed unique names, we could just
/// compare those, but this would not work for stripped bitcodes or for those
/// few symbols without a name.
class GlobalNumberState {
struct Config : ValueMapConfig<GlobalValue*> {
enum { FollowRAUW = false };
};
// Each GlobalValue is mapped to an identifier. The Config ensures when RAUW
// occurs, the mapping does not change. Tracking changes is unnecessary, and
// also problematic for weak symbols (which may be overwritten).
typedef ValueMap<GlobalValue *, uint64_t, Config> ValueNumberMap;
ValueNumberMap GlobalNumbers;
// The next unused serial number to assign to a global.
uint64_t NextNumber;
public:
GlobalNumberState() : GlobalNumbers(), NextNumber(0) {}
uint64_t getNumber(GlobalValue* Global) {
ValueNumberMap::iterator MapIter;
bool Inserted;
std::tie(MapIter, Inserted) = GlobalNumbers.insert({Global, NextNumber});
if (Inserted)
NextNumber++;
return MapIter->second;
}
void clear() {
GlobalNumbers.clear();
}
};
/// FunctionComparator - Compares two functions to determine whether or not
/// they will generate machine code with the same behaviour. DataLayout is
/// used if available. The comparator always fails conservatively (erring on the
/// side of claiming that two functions are different).
class FunctionComparator {
public:
FunctionComparator(const Function *F1, const Function *F2,
GlobalNumberState* GN)
: FnL(F1), FnR(F2), GlobalNumbers(GN) {}
/// Test whether the two functions have equivalent behaviour.
int compare();
/// Hash a function. Equivalent functions will have the same hash, and unequal
/// functions will have different hashes with high probability.
typedef uint64_t FunctionHash;
static FunctionHash functionHash(Function &);
protected:
/// Start the comparison.
void beginCompare() {
sn_mapL.clear();
sn_mapR.clear();
}
/// Compares the signature and other general attributes of the two functions.
int compareSignature() const;
/// Test whether two basic blocks have equivalent behaviour.
int cmpBasicBlocks(const BasicBlock *BBL, const BasicBlock *BBR) const;
/// Constants comparison.
/// Its analog to lexicographical comparison between hypothetical numbers
/// of next format:
/// <bitcastability-trait><raw-bit-contents>
///
/// 1. Bitcastability.
/// Check whether L's type could be losslessly bitcasted to R's type.
/// On this stage method, in case when lossless bitcast is not possible
/// method returns -1 or 1, thus also defining which type is greater in
/// context of bitcastability.
/// Stage 0: If types are equal in terms of cmpTypes, then we can go straight
/// to the contents comparison.
/// If types differ, remember types comparison result and check
/// whether we still can bitcast types.
/// Stage 1: Types that satisfies isFirstClassType conditions are always
/// greater then others.
/// Stage 2: Vector is greater then non-vector.
/// If both types are vectors, then vector with greater bitwidth is
/// greater.
/// If both types are vectors with the same bitwidth, then types
/// are bitcastable, and we can skip other stages, and go to contents
/// comparison.
/// Stage 3: Pointer types are greater than non-pointers. If both types are
/// pointers of the same address space - go to contents comparison.
/// Different address spaces: pointer with greater address space is
/// greater.
/// Stage 4: Types are neither vectors, nor pointers. And they differ.
/// We don't know how to bitcast them. So, we better don't do it,
/// and return types comparison result (so it determines the
/// relationship among constants we don't know how to bitcast).
///
/// Just for clearance, let's see how the set of constants could look
/// on single dimension axis:
///
/// [NFCT], [FCT, "others"], [FCT, pointers], [FCT, vectors]
/// Where: NFCT - Not a FirstClassType
/// FCT - FirstClassTyp:
///
/// 2. Compare raw contents.
/// It ignores types on this stage and only compares bits from L and R.
/// Returns 0, if L and R has equivalent contents.
/// -1 or 1 if values are different.
/// Pretty trivial:
/// 2.1. If contents are numbers, compare numbers.
/// Ints with greater bitwidth are greater. Ints with same bitwidths
/// compared by their contents.
/// 2.2. "And so on". Just to avoid discrepancies with comments
/// perhaps it would be better to read the implementation itself.
/// 3. And again about overall picture. Let's look back at how the ordered set
/// of constants will look like:
/// [NFCT], [FCT, "others"], [FCT, pointers], [FCT, vectors]
///
/// Now look, what could be inside [FCT, "others"], for example:
/// [FCT, "others"] =
/// [
/// [double 0.1], [double 1.23],
/// [i32 1], [i32 2],
/// { double 1.0 }, ; StructTyID, NumElements = 1
/// { i32 1 }, ; StructTyID, NumElements = 1
/// { double 1, i32 1 }, ; StructTyID, NumElements = 2
/// { i32 1, double 1 } ; StructTyID, NumElements = 2
/// ]
///
/// Let's explain the order. Float numbers will be less than integers, just
/// because of cmpType terms: FloatTyID < IntegerTyID.
/// Floats (with same fltSemantics) are sorted according to their value.
/// Then you can see integers, and they are, like a floats,
/// could be easy sorted among each others.
/// The structures. Structures are grouped at the tail, again because of their
/// TypeID: StructTyID > IntegerTyID > FloatTyID.
/// Structures with greater number of elements are greater. Structures with
/// greater elements going first are greater.
/// The same logic with vectors, arrays and other possible complex types.
///
/// Bitcastable constants.
/// Let's assume, that some constant, belongs to some group of
/// "so-called-equal" values with different types, and at the same time
/// belongs to another group of constants with equal types
/// and "really" equal values.
///
/// Now, prove that this is impossible:
///
/// If constant A with type TyA is bitcastable to B with type TyB, then:
/// 1. All constants with equal types to TyA, are bitcastable to B. Since
/// those should be vectors (if TyA is vector), pointers
/// (if TyA is pointer), or else (if TyA equal to TyB), those types should
/// be equal to TyB.
/// 2. All constants with non-equal, but bitcastable types to TyA, are
/// bitcastable to B.
/// Once again, just because we allow it to vectors and pointers only.
/// This statement could be expanded as below:
/// 2.1. All vectors with equal bitwidth to vector A, has equal bitwidth to
/// vector B, and thus bitcastable to B as well.
/// 2.2. All pointers of the same address space, no matter what they point to,
/// bitcastable. So if C is pointer, it could be bitcasted to A and to B.
/// So any constant equal or bitcastable to A is equal or bitcastable to B.
/// QED.
///
/// In another words, for pointers and vectors, we ignore top-level type and
/// look at their particular properties (bit-width for vectors, and
/// address space for pointers).
/// If these properties are equal - compare their contents.
int cmpConstants(const Constant *L, const Constant *R) const;
/// Compares two global values by number. Uses the GlobalNumbersState to
/// identify the same gobals across function calls.
int cmpGlobalValues(GlobalValue *L, GlobalValue *R) const;
/// Assign or look up previously assigned numbers for the two values, and
/// return whether the numbers are equal. Numbers are assigned in the order
/// visited.
/// Comparison order:
/// Stage 0: Value that is function itself is always greater then others.
/// If left and right values are references to their functions, then
/// they are equal.
/// Stage 1: Constants are greater than non-constants.
/// If both left and right are constants, then the result of
/// cmpConstants is used as cmpValues result.
/// Stage 2: InlineAsm instances are greater than others. If both left and
/// right are InlineAsm instances, InlineAsm* pointers casted to
/// integers and compared as numbers.
/// Stage 3: For all other cases we compare order we meet these values in
/// their functions. If right value was met first during scanning,
/// then left value is greater.
/// In another words, we compare serial numbers, for more details
/// see comments for sn_mapL and sn_mapR.
int cmpValues(const Value *L, const Value *R) const;
/// Compare two Instructions for equivalence, similar to
/// Instruction::isSameOperationAs.
///
/// Stages are listed in "most significant stage first" order:
/// On each stage below, we do comparison between some left and right
/// operation parts. If parts are non-equal, we assign parts comparison
/// result to the operation comparison result and exit from method.
/// Otherwise we proceed to the next stage.
/// Stages:
/// 1. Operations opcodes. Compared as numbers.
/// 2. Number of operands.
/// 3. Operation types. Compared with cmpType method.
/// 4. Compare operation subclass optional data as stream of bytes:
/// just convert it to integers and call cmpNumbers.
/// 5. Compare in operation operand types with cmpType in
/// most significant operand first order.
/// 6. Last stage. Check operations for some specific attributes.
/// For example, for Load it would be:
/// 6.1.Load: volatile (as boolean flag)
/// 6.2.Load: alignment (as integer numbers)
/// 6.3.Load: ordering (as underlying enum class value)
/// 6.4.Load: synch-scope (as integer numbers)
/// 6.5.Load: range metadata (as integer ranges)
/// On this stage its better to see the code, since its not more than 10-15
/// strings for particular instruction, and could change sometimes.
///
/// Sets \p needToCmpOperands to true if the operands of the instructions
/// still must be compared afterwards. In this case it's already guaranteed
/// that both instructions have the same number of operands.
int cmpOperations(const Instruction *L, const Instruction *R,
bool &needToCmpOperands) const;
/// cmpType - compares two types,
/// defines total ordering among the types set.
///
/// Return values:
/// 0 if types are equal,
/// -1 if Left is less than Right,
/// +1 if Left is greater than Right.
///
/// Description:
/// Comparison is broken onto stages. Like in lexicographical comparison
/// stage coming first has higher priority.
/// On each explanation stage keep in mind total ordering properties.
///
/// 0. Before comparison we coerce pointer types of 0 address space to
/// integer.
/// We also don't bother with same type at left and right, so
/// just return 0 in this case.
///
/// 1. If types are of different kind (different type IDs).
/// Return result of type IDs comparison, treating them as numbers.
/// 2. If types are integers, check that they have the same width. If they
/// are vectors, check that they have the same count and subtype.
/// 3. Types have the same ID, so check whether they are one of:
/// * Void
/// * Float
/// * Double
/// * X86_FP80
/// * FP128
/// * PPC_FP128
/// * Label
/// * Metadata
/// We can treat these types as equal whenever their IDs are same.
/// 4. If Left and Right are pointers, return result of address space
/// comparison (numbers comparison). We can treat pointer types of same
/// address space as equal.
/// 5. If types are complex.
/// Then both Left and Right are to be expanded and their element types will
/// be checked with the same way. If we get Res != 0 on some stage, return it.
/// Otherwise return 0.
/// 6. For all other cases put llvm_unreachable.
int cmpTypes(Type *TyL, Type *TyR) const;
int cmpNumbers(uint64_t L, uint64_t R) const;
int cmpAPInts(const APInt &L, const APInt &R) const;
int cmpAPFloats(const APFloat &L, const APFloat &R) const;
int cmpMem(StringRef L, StringRef R) const;
// The two functions undergoing comparison.
const Function *FnL, *FnR;
private:
int cmpOrderings(AtomicOrdering L, AtomicOrdering R) const;
int cmpInlineAsm(const InlineAsm *L, const InlineAsm *R) const;
int cmpAttrs(const AttributeSet L, const AttributeSet R) const;
int cmpRangeMetadata(const MDNode *L, const MDNode *R) const;
int cmpOperandBundlesSchema(const Instruction *L, const Instruction *R) const;
/// Compare two GEPs for equivalent pointer arithmetic.
/// Parts to be compared for each comparison stage,
/// most significant stage first:
/// 1. Address space. As numbers.
/// 2. Constant offset, (using GEPOperator::accumulateConstantOffset method).
/// 3. Pointer operand type (using cmpType method).
/// 4. Number of operands.
/// 5. Compare operands, using cmpValues method.
int cmpGEPs(const GEPOperator *GEPL, const GEPOperator *GEPR) const;
int cmpGEPs(const GetElementPtrInst *GEPL,
const GetElementPtrInst *GEPR) const {
return cmpGEPs(cast<GEPOperator>(GEPL), cast<GEPOperator>(GEPR));
}
/// Assign serial numbers to values from left function, and values from
/// right function.
/// Explanation:
/// Being comparing functions we need to compare values we meet at left and
/// right sides.
/// Its easy to sort things out for external values. It just should be
/// the same value at left and right.
/// But for local values (those were introduced inside function body)
/// we have to ensure they were introduced at exactly the same place,
/// and plays the same role.
/// Let's assign serial number to each value when we meet it first time.
/// Values that were met at same place will be with same serial numbers.
/// In this case it would be good to explain few points about values assigned
/// to BBs and other ways of implementation (see below).
///
/// 1. Safety of BB reordering.
/// It's safe to change the order of BasicBlocks in function.
/// Relationship with other functions and serial numbering will not be
/// changed in this case.
/// As follows from FunctionComparator::compare(), we do CFG walk: we start
/// from the entry, and then take each terminator. So it doesn't matter how in
/// fact BBs are ordered in function. And since cmpValues are called during
/// this walk, the numbering depends only on how BBs located inside the CFG.
/// So the answer is - yes. We will get the same numbering.
///
/// 2. Impossibility to use dominance properties of values.
/// If we compare two instruction operands: first is usage of local
/// variable AL from function FL, and second is usage of local variable AR
/// from FR, we could compare their origins and check whether they are
/// defined at the same place.
/// But, we are still not able to compare operands of PHI nodes, since those
/// could be operands from further BBs we didn't scan yet.
/// So it's impossible to use dominance properties in general.
mutable DenseMap<const Value*, int> sn_mapL, sn_mapR;
// The global state we will use
GlobalNumberState* GlobalNumbers;
};
}
#endif // LLVM_TRANSFORMS_UTILS_FUNCTIONCOMPARATOR_H

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lib/Transforms/IPO/MergeFunctions.cpp
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1
lib/Transforms/Utils/CMakeLists.txt
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@ -13,6 +13,7 @@ add_llvm_library(LLVMTransformUtils
DemoteRegToStack.cpp
Evaluator.cpp
FlattenCFG.cpp
FunctionComparator.cpp
FunctionImportUtils.cpp
GlobalStatus.cpp
InlineFunction.cpp

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//===- FunctionComparator.h - Function Comparator -------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the FunctionComparator and GlobalNumberState classes
// which are used by the MergeFunctions pass for comparing functions.
//
//===----------------------------------------------------------------------===//
#include "llvm/Transforms/Utils/FunctionComparator.h"
#include "llvm/ADT/SmallSet.h"
#include "llvm/IR/CallSite.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/InlineAsm.h"
#include "llvm/IR/Module.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
#define DEBUG_TYPE "functioncomparator"
int FunctionComparator::cmpNumbers(uint64_t L, uint64_t R) const {
if (L < R) return -1;
if (L > R) return 1;
return 0;
}
int FunctionComparator::cmpOrderings(AtomicOrdering L, AtomicOrdering R) const {
if ((int)L < (int)R) return -1;
if ((int)L > (int)R) return 1;
return 0;
}
int FunctionComparator::cmpAPInts(const APInt &L, const APInt &R) const {
if (int Res = cmpNumbers(L.getBitWidth(), R.getBitWidth()))
return Res;
if (L.ugt(R)) return 1;
if (R.ugt(L)) return -1;
return 0;
}
int FunctionComparator::cmpAPFloats(const APFloat &L, const APFloat &R) const {
// Floats are ordered first by semantics (i.e. float, double, half, etc.),
// then by value interpreted as a bitstring (aka APInt).
const fltSemantics &SL = L.getSemantics(), &SR = R.getSemantics();
if (int Res = cmpNumbers(APFloat::semanticsPrecision(SL),
APFloat::semanticsPrecision(SR)))
return Res;
if (int Res = cmpNumbers(APFloat::semanticsMaxExponent(SL),
APFloat::semanticsMaxExponent(SR)))
return Res;
if (int Res = cmpNumbers(APFloat::semanticsMinExponent(SL),
APFloat::semanticsMinExponent(SR)))
return Res;
if (int Res = cmpNumbers(APFloat::semanticsSizeInBits(SL),
APFloat::semanticsSizeInBits(SR)))
return Res;
return cmpAPInts(L.bitcastToAPInt(), R.bitcastToAPInt());
}
int FunctionComparator::cmpMem(StringRef L, StringRef R) const {
// Prevent heavy comparison, compare sizes first.
if (int Res = cmpNumbers(L.size(), R.size()))
return Res;
// Compare strings lexicographically only when it is necessary: only when
// strings are equal in size.
return L.compare(R);
}
int FunctionComparator::cmpAttrs(const AttributeSet L,
const AttributeSet R) const {
if (int Res = cmpNumbers(L.getNumSlots(), R.getNumSlots()))
return Res;
for (unsigned i = 0, e = L.getNumSlots(); i != e; ++i) {
AttributeSet::iterator LI = L.begin(i), LE = L.end(i), RI = R.begin(i),
RE = R.end(i);
for (; LI != LE && RI != RE; ++LI, ++RI) {
Attribute LA = *LI;
Attribute RA = *RI;
if (LA < RA)
return -1;
if (RA < LA)
return 1;
}
if (LI != LE)
return 1;
if (RI != RE)
return -1;
}
return 0;
}
int FunctionComparator::cmpRangeMetadata(const MDNode *L,
const MDNode *R) const {
if (L == R)
return 0;
if (!L)
return -1;
if (!R)
return 1;
// Range metadata is a sequence of numbers. Make sure they are the same
// sequence.
// TODO: Note that as this is metadata, it is possible to drop and/or merge
// this data when considering functions to merge. Thus this comparison would
// return 0 (i.e. equivalent), but merging would become more complicated
// because the ranges would need to be unioned. It is not likely that
// functions differ ONLY in this metadata if they are actually the same
// function semantically.
if (int Res = cmpNumbers(L->getNumOperands(), R->getNumOperands()))
return Res;
for (size_t I = 0; I < L->getNumOperands(); ++I) {
ConstantInt *LLow = mdconst::extract<ConstantInt>(L->getOperand(I));
ConstantInt *RLow = mdconst::extract<ConstantInt>(R->getOperand(I));
if (int Res = cmpAPInts(LLow->getValue(), RLow->getValue()))
return Res;
}
return 0;
}
int FunctionComparator::cmpOperandBundlesSchema(const Instruction *L,
const Instruction *R) const {
ImmutableCallSite LCS(L);
ImmutableCallSite RCS(R);
assert(LCS && RCS && "Must be calls or invokes!");
assert(LCS.isCall() == RCS.isCall() && "Can't compare otherwise!");
if (int Res =
cmpNumbers(LCS.getNumOperandBundles(), RCS.getNumOperandBundles()))
return Res;
for (unsigned i = 0, e = LCS.getNumOperandBundles(); i != e; ++i) {
auto OBL = LCS.getOperandBundleAt(i);
auto OBR = RCS.getOperandBundleAt(i);
if (int Res = OBL.getTagName().compare(OBR.getTagName()))
return Res;
if (int Res = cmpNumbers(OBL.Inputs.size(), OBR.Inputs.size()))
return Res;
}
return 0;
}
/// Constants comparison:
/// 1. Check whether type of L constant could be losslessly bitcasted to R
/// type.
/// 2. Compare constant contents.
/// For more details see declaration comments.
int FunctionComparator::cmpConstants(const Constant *L,
const Constant *R) const {
Type *TyL = L->getType();
Type *TyR = R->getType();
// Check whether types are bitcastable. This part is just re-factored
// Type::canLosslesslyBitCastTo method, but instead of returning true/false,
// we also pack into result which type is "less" for us.
int TypesRes = cmpTypes(TyL, TyR);
if (TypesRes != 0) {
// Types are different, but check whether we can bitcast them.
if (!TyL->isFirstClassType()) {
if (TyR->isFirstClassType())
return -1;
// Neither TyL nor TyR are values of first class type. Return the result
// of comparing the types
return TypesRes;
}
if (!TyR->isFirstClassType()) {
if (TyL->isFirstClassType())
return 1;
return TypesRes;
}
// Vector -> Vector conversions are always lossless if the two vector types
// have the same size, otherwise not.
unsigned TyLWidth = 0;
unsigned TyRWidth = 0;
if (auto *VecTyL = dyn_cast<VectorType>(TyL))
TyLWidth = VecTyL->getBitWidth();
if (auto *VecTyR = dyn_cast<VectorType>(TyR))
TyRWidth = VecTyR->getBitWidth();
if (TyLWidth != TyRWidth)
return cmpNumbers(TyLWidth, TyRWidth);
// Zero bit-width means neither TyL nor TyR are vectors.
if (!TyLWidth) {
PointerType *PTyL = dyn_cast<PointerType>(TyL);
PointerType *PTyR = dyn_cast<PointerType>(TyR);
if (PTyL && PTyR) {
unsigned AddrSpaceL = PTyL->getAddressSpace();
unsigned AddrSpaceR = PTyR->getAddressSpace();
if (int Res = cmpNumbers(AddrSpaceL, AddrSpaceR))
return Res;
}
if (PTyL)
return 1;
if (PTyR)
return -1;
// TyL and TyR aren't vectors, nor pointers. We don't know how to
// bitcast them.
return TypesRes;
}
}
// OK, types are bitcastable, now check constant contents.
if (L->isNullValue() && R->isNullValue())
return TypesRes;
if (L->isNullValue() && !R->isNullValue())
return 1;
if (!L->isNullValue() && R->isNullValue())
return -1;
auto GlobalValueL = const_cast<GlobalValue*>(dyn_cast<GlobalValue>(L));
auto GlobalValueR = const_cast<GlobalValue*>(dyn_cast<GlobalValue>(R));
if (GlobalValueL && GlobalValueR) {
return cmpGlobalValues(GlobalValueL, GlobalValueR);
}
if (int Res = cmpNumbers(L->getValueID(), R->getValueID()))
return Res;
if (const auto *SeqL = dyn_cast<ConstantDataSequential>(L)) {
const auto *SeqR = cast<ConstantDataSequential>(R);
// This handles ConstantDataArray and ConstantDataVector. Note that we
// compare the two raw data arrays, which might differ depending on the host
// endianness. This isn't a problem though, because the endiness of a module
// will affect the order of the constants, but this order is the same
// for a given input module and host platform.
return cmpMem(SeqL->getRawDataValues(), SeqR->getRawDataValues());
}
switch (L->getValueID()) {
case Value::UndefValueVal:
case Value::ConstantTokenNoneVal:
return TypesRes;
case Value::ConstantIntVal: {
const APInt &LInt = cast<ConstantInt>(L)->getValue();
const APInt &RInt = cast<ConstantInt>(R)->getValue();
return cmpAPInts(LInt, RInt);
}
case Value::ConstantFPVal: {
const APFloat &LAPF = cast<ConstantFP>(L)->getValueAPF();
const APFloat &RAPF = cast<ConstantFP>(R)->getValueAPF();
return cmpAPFloats(LAPF, RAPF);
}
case Value::ConstantArrayVal: {
const ConstantArray *LA = cast<ConstantArray>(L);
const ConstantArray *RA = cast<ConstantArray>(R);
uint64_t NumElementsL = cast<ArrayType>(TyL)->getNumElements();
uint64_t NumElementsR = cast<ArrayType>(TyR)->getNumElements();
if (int Res = cmpNumbers(NumElementsL, NumElementsR))
return Res;
for (uint64_t i = 0; i < NumElementsL; ++i) {
if (int Res = cmpConstants(cast<Constant>(LA->getOperand(i)),
cast<Constant>(RA->getOperand(i))))
return Res;
}
return 0;
}
case Value::ConstantStructVal: {
const ConstantStruct *LS = cast<ConstantStruct>(L);
const ConstantStruct *RS = cast<ConstantStruct>(R);
unsigned NumElementsL = cast<StructType>(TyL)->getNumElements();
unsigned NumElementsR = cast<StructType>(TyR)->getNumElements();
if (int Res = cmpNumbers(NumElementsL, NumElementsR))
return Res;
for (unsigned i = 0; i != NumElementsL; ++i) {
if (int Res = cmpConstants(cast<Constant>(LS->getOperand(i)),
cast<Constant>(RS->getOperand(i))))
return Res;
}
return 0;
}
case Value::ConstantVectorVal: {
const ConstantVector *LV = cast<ConstantVector>(L);
const ConstantVector *RV = cast<ConstantVector>(R);
unsigned NumElementsL = cast<VectorType>(TyL)->getNumElements();
unsigned NumElementsR = cast<VectorType>(TyR)->getNumElements();
if (int Res = cmpNumbers(NumElementsL, NumElementsR))
return Res;
for (uint64_t i = 0; i < NumElementsL; ++i) {
if (int Res = cmpConstants(cast<Constant>(LV->getOperand(i)),
cast<Constant>(RV->getOperand(i))))
return Res;
}
return 0;
}
case Value::ConstantExprVal: {
const ConstantExpr *LE = cast<ConstantExpr>(L);
const ConstantExpr *RE = cast<ConstantExpr>(R);
unsigned NumOperandsL = LE->getNumOperands();
unsigned NumOperandsR = RE->getNumOperands();
if (int Res = cmpNumbers(NumOperandsL, NumOperandsR))
return Res;
for (unsigned i = 0; i < NumOperandsL; ++i) {
if (int Res = cmpConstants(cast<Constant>(LE->getOperand(i)),
cast<Constant>(RE->getOperand(i))))
return Res;
}
return 0;
}
case Value::BlockAddressVal: {
const BlockAddress *LBA = cast<BlockAddress>(L);
const BlockAddress *RBA = cast<BlockAddress>(R);
if (int Res = cmpValues(LBA->getFunction(), RBA->getFunction()))
return Res;
if (LBA->getFunction() == RBA->getFunction()) {
// They are BBs in the same function. Order by which comes first in the
// BB order of the function. This order is deterministic.
Function* F = LBA->getFunction();
BasicBlock *LBB = LBA->getBasicBlock();
BasicBlock *RBB = RBA->getBasicBlock();
if (LBB == RBB)
return 0;
for(BasicBlock &BB : F->getBasicBlockList()) {
if (&BB == LBB) {
assert(&BB != RBB);
return -1;
}
if (&BB == RBB)
return 1;
}
llvm_unreachable("Basic Block Address does not point to a basic block in "
"its function.");
return -1;
} else {
// cmpValues said the functions are the same. So because they aren't
// literally the same pointer, they must respectively be the left and
// right functions.
assert(LBA->getFunction() == FnL && RBA->getFunction() == FnR);
// cmpValues will tell us if these are equivalent BasicBlocks, in the
// context of their respective functions.
return cmpValues(LBA->getBasicBlock(), RBA->getBasicBlock());
}
}
default: // Unknown constant, abort.
DEBUG(dbgs() << "Looking at valueID " << L->getValueID() << "\n");
llvm_unreachable("Constant ValueID not recognized.");
return -1;
}
}
int FunctionComparator::cmpGlobalValues(GlobalValue *L, GlobalValue *R) const {
return cmpNumbers(GlobalNumbers->getNumber(L), GlobalNumbers->getNumber(R));
}
/// cmpType - compares two types,
/// defines total ordering among the types set.
/// See method declaration comments for more details.
int FunctionComparator::cmpTypes(Type *TyL, Type *TyR) const {
PointerType *PTyL = dyn_cast<PointerType>(TyL);
PointerType *PTyR = dyn_cast<PointerType>(TyR);
const DataLayout &DL = FnL->getParent()->getDataLayout();
if (PTyL && PTyL->getAddressSpace() == 0)
TyL = DL.getIntPtrType(TyL);
if (PTyR && PTyR->getAddressSpace() == 0)
TyR = DL.getIntPtrType(TyR);
if (TyL == TyR)
return 0;
if (int Res = cmpNumbers(TyL->getTypeID(), TyR->getTypeID()))
return Res;
switch (TyL->getTypeID()) {
default:
llvm_unreachable("Unknown type!");
// Fall through in Release mode.
LLVM_FALLTHROUGH;
case Type::IntegerTyID:
return cmpNumbers(cast<IntegerType>(TyL)->getBitWidth(),
cast<IntegerType>(TyR)->getBitWidth());
case Type::VectorTyID: {
VectorType *VTyL = cast<VectorType>(TyL), *VTyR = cast<VectorType>(TyR);
if (int Res = cmpNumbers(VTyL->getNumElements(), VTyR->getNumElements()))
return Res;
return cmpTypes(VTyL->getElementType(), VTyR->getElementType());
}
// TyL == TyR would have returned true earlier, because types are uniqued.
case Type::VoidTyID:
case Type::FloatTyID:
case Type::DoubleTyID:
case Type::X86_FP80TyID:
case Type::FP128TyID:
case Type::PPC_FP128TyID:
case Type::LabelTyID:
case Type::MetadataTyID:
case Type::TokenTyID:
return 0;
case Type::PointerTyID: {
assert(PTyL && PTyR && "Both types must be pointers here.");
return cmpNumbers(PTyL->getAddressSpace(), PTyR->getAddressSpace());
}
case Type::StructTyID: {
StructType *STyL = cast<StructType>(TyL);
StructType *STyR = cast<StructType>(TyR);
if (STyL->getNumElements() != STyR->getNumElements())
return cmpNumbers(STyL->getNumElements(), STyR->getNumElements());
if (STyL->isPacked() != STyR->isPacked())
return cmpNumbers(STyL->isPacked(), STyR->isPacked());
for (unsigned i = 0, e = STyL->getNumElements(); i != e; ++i) {
if (int Res = cmpTypes(STyL->getElementType(i), STyR->getElementType(i)))
return Res;
}
return 0;
}
case Type::FunctionTyID: {
FunctionType *FTyL = cast<FunctionType>(TyL);
FunctionType *FTyR = cast<FunctionType>(TyR);
if (FTyL->getNumParams() != FTyR->getNumParams())
return cmpNumbers(FTyL->getNumParams(), FTyR->getNumParams());
if (FTyL->isVarArg() != FTyR->isVarArg())
return cmpNumbers(FTyL->isVarArg(), FTyR->isVarArg());
if (int Res = cmpTypes(FTyL->getReturnType(), FTyR->getReturnType()))
return Res;
for (unsigned i = 0, e = FTyL->getNumParams(); i != e; ++i) {
if (int Res = cmpTypes(FTyL->getParamType(i), FTyR->getParamType(i)))
return Res;
}
return 0;
}
case Type::ArrayTyID: {
ArrayType *ATyL = cast<ArrayType>(TyL);
ArrayType *ATyR = cast<ArrayType>(TyR);
if (ATyL->getNumElements() != ATyR->getNumElements())
return cmpNumbers(ATyL->getNumElements(), ATyR->getNumElements());
return cmpTypes(ATyL->getElementType(), ATyR->getElementType());
}
}
}
// Determine whether the two operations are the same except that pointer-to-A
// and pointer-to-B are equivalent. This should be kept in sync with
// Instruction::isSameOperationAs.
// Read method declaration comments for more details.
int FunctionComparator::cmpOperations(const Instruction *L,
const Instruction *R,
bool &needToCmpOperands) const {
needToCmpOperands = true;
if (int Res = cmpValues(L, R))
return Res;
// Differences from Instruction::isSameOperationAs:
// * replace type comparison with calls to cmpTypes.
// * we test for I->getRawSubclassOptionalData (nuw/nsw/tail) at the top.
// * because of the above, we don't test for the tail bit on calls later on.
if (int Res = cmpNumbers(L->getOpcode(), R->getOpcode()))
return Res;
if (const GetElementPtrInst *GEPL = dyn_cast<GetElementPtrInst>(L)) {
needToCmpOperands = false;
const GetElementPtrInst *GEPR = cast<GetElementPtrInst>(R);
if (int Res =
cmpValues(GEPL->getPointerOperand(), GEPR->getPointerOperand()))
return Res;
return cmpGEPs(GEPL, GEPR);
}
if (int Res = cmpNumbers(L->getNumOperands(), R->getNumOperands()))
return Res;
if (int Res = cmpTypes(L->getType(), R->getType()))
return Res;
if (int Res = cmpNumbers(L->getRawSubclassOptionalData(),
R->getRawSubclassOptionalData()))
return Res;
// We have two instructions of identical opcode and #operands. Check to see
// if all operands are the same type
for (unsigned i = 0, e = L->getNumOperands(); i != e; ++i) {
if (int Res =
cmpTypes(L->getOperand(i)->getType(), R->getOperand(i)->getType()))
return Res;
}
// Check special state that is a part of some instructions.
if (const AllocaInst *AI = dyn_cast<AllocaInst>(L)) {
if (int Res = cmpTypes(AI->getAllocatedType(),
cast<AllocaInst>(R)->getAllocatedType()))
return Res;
return cmpNumbers(AI->getAlignment(), cast<AllocaInst>(R)->getAlignment());
}
if (const LoadInst *LI = dyn_cast<LoadInst>(L)) {
if (int Res = cmpNumbers(LI->isVolatile(), cast<LoadInst>(R)->isVolatile()))
return Res;
if (int Res =
cmpNumbers(LI->getAlignment(), cast<LoadInst>(R)->getAlignment()))
return Res;
if (int Res =
cmpOrderings(LI->getOrdering(), cast<LoadInst>(R)->getOrdering()))
return Res;
if (int Res =
cmpNumbers(LI->getSynchScope(), cast<LoadInst>(R)->getSynchScope()))
return Res;
return cmpRangeMetadata(LI->getMetadata(LLVMContext::MD_range),
cast<LoadInst>(R)->getMetadata(LLVMContext::MD_range));
}
if (const StoreInst *SI = dyn_cast<StoreInst>(L)) {
if (int Res =
cmpNumbers(SI->isVolatile(), cast<StoreInst>(R)->isVolatile()))
return Res;
if (int Res =
cmpNumbers(SI->getAlignment(), cast<StoreInst>(R)->getAlignment()))
return Res;
if (int Res =
cmpOrderings(SI->getOrdering(), cast<StoreInst>(R)->getOrdering()))
return Res;
return cmpNumbers(SI->getSynchScope(), cast<StoreInst>(R)->getSynchScope());
}
if (const CmpInst *CI = dyn_cast<CmpInst>(L))
return cmpNumbers(CI->getPredicate(), cast<CmpInst>(R)->getPredicate());
if (const CallInst *CI = dyn_cast<CallInst>(L)) {
if (int Res = cmpNumbers(CI->getCallingConv(),
cast<CallInst>(R)->getCallingConv()))
return Res;
if (int Res =
cmpAttrs(CI->getAttributes(), cast<CallInst>(R)->getAttributes()))
return Res;
if (int Res = cmpOperandBundlesSchema(CI, R))
return Res;
return cmpRangeMetadata(
CI->getMetadata(LLVMContext::MD_range),
cast<CallInst>(R)->getMetadata(LLVMContext::MD_range));
}
if (const InvokeInst *II = dyn_cast<InvokeInst>(L)) {
if (int Res = cmpNumbers(II->getCallingConv(),
cast<InvokeInst>(R)->getCallingConv()))
return Res;
if (int Res =
cmpAttrs(II->getAttributes(), cast<InvokeInst>(R)->getAttributes()))
return Res;
if (int Res = cmpOperandBundlesSchema(II, R))
return Res;
return cmpRangeMetadata(
II->getMetadata(LLVMContext::MD_range),
cast<InvokeInst>(R)->getMetadata(LLVMContext::MD_range));
}
if (const InsertValueInst *IVI = dyn_cast<InsertValueInst>(L)) {
ArrayRef<unsigned> LIndices = IVI->getIndices();
ArrayRef<unsigned> RIndices = cast<InsertValueInst>(R)->getIndices();
if (int Res = cmpNumbers(LIndices.size(), RIndices.size()))
return Res;
for (size_t i = 0, e = LIndices.size(); i != e; ++i) {
if (int Res = cmpNumbers(LIndices[i], RIndices[i]))
return Res;
}
return 0;
}
if (const ExtractValueInst *EVI = dyn_cast<ExtractValueInst>(L)) {
ArrayRef<unsigned> LIndices = EVI->getIndices();
ArrayRef<unsigned> RIndices = cast<ExtractValueInst>(R)->getIndices();
if (int Res = cmpNumbers(LIndices.size(), RIndices.size()))
return Res;
for (size_t i = 0, e = LIndices.size(); i != e; ++i) {
if (int Res = cmpNumbers(LIndices[i], RIndices[i]))
return Res;
}
}
if (const FenceInst *FI = dyn_cast<FenceInst>(L)) {
if (int Res =
cmpOrderings(FI->getOrdering(), cast<FenceInst>(R)->getOrdering()))
return Res;
return cmpNumbers(FI->getSynchScope(), cast<FenceInst>(R)->getSynchScope());
}
if (const AtomicCmpXchgInst *CXI = dyn_cast<AtomicCmpXchgInst>(L)) {
if (int Res = cmpNumbers(CXI->isVolatile(),
cast<AtomicCmpXchgInst>(R)->isVolatile()))
return Res;
if (int Res = cmpNumbers(CXI->isWeak(),
cast<AtomicCmpXchgInst>(R)->isWeak()))
return Res;
if (int Res =
cmpOrderings(CXI->getSuccessOrdering(),
cast<AtomicCmpXchgInst>(R)->getSuccessOrdering()))
return Res;
if (int Res =
cmpOrderings(CXI->getFailureOrdering(),
cast<AtomicCmpXchgInst>(R)->getFailureOrdering()))
return Res;
return cmpNumbers(CXI->getSynchScope(),
cast<AtomicCmpXchgInst>(R)->getSynchScope());
}
if (const AtomicRMWInst *RMWI = dyn_cast<AtomicRMWInst>(L)) {
if (int Res = cmpNumbers(RMWI->getOperation(),
cast<AtomicRMWInst>(R)->getOperation()))
return Res;
if (int Res = cmpNumbers(RMWI->isVolatile(),
cast<AtomicRMWInst>(R)->isVolatile()))
return Res;
if (int Res = cmpOrderings(RMWI->getOrdering(),
cast<AtomicRMWInst>(R)->getOrdering()))
return Res;
return cmpNumbers(RMWI->getSynchScope(),
cast<AtomicRMWInst>(R)->getSynchScope());
}
if (const PHINode *PNL = dyn_cast<PHINode>(L)) {
const PHINode *PNR = cast<PHINode>(R);
// Ensure that in addition to the incoming values being identical
// (checked by the caller of this function), the incoming blocks
// are also identical.
for (unsigned i = 0, e = PNL->getNumIncomingValues(); i != e; ++i) {
if (int Res =
cmpValues(PNL->getIncomingBlock(i), PNR->getIncomingBlock(i)))
return Res;
}
}
return 0;
}
// Determine whether two GEP operations perform the same underlying arithmetic.
// Read method declaration comments for more details.
int FunctionComparator::cmpGEPs(const GEPOperator *GEPL,
const GEPOperator *GEPR) const {
unsigned int ASL = GEPL->getPointerAddressSpace();
unsigned int ASR = GEPR->getPointerAddressSpace();
if (int Res = cmpNumbers(ASL, ASR))
return Res;
// When we have target data, we can reduce the GEP down to the value in bytes
// added to the address.
const DataLayout &DL = FnL->getParent()->getDataLayout();
unsigned BitWidth = DL.getPointerSizeInBits(ASL);
APInt OffsetL(BitWidth, 0), OffsetR(BitWidth, 0);
if (GEPL->accumulateConstantOffset(DL, OffsetL) &&
GEPR->accumulateConstantOffset(DL, OffsetR))
return cmpAPInts(OffsetL, OffsetR);
if (int Res = cmpTypes(GEPL->getSourceElementType(),
GEPR->getSourceElementType()))
return Res;
if (int Res = cmpNumbers(GEPL->getNumOperands(), GEPR->getNumOperands()))
return Res;
for (unsigned i = 0, e = GEPL->getNumOperands(); i != e; ++i) {
if (int Res = cmpValues(GEPL->getOperand(i), GEPR->getOperand(i)))
return Res;
}
return 0;
}
int FunctionComparator::cmpInlineAsm(const InlineAsm *L,
const InlineAsm *R) const {
// InlineAsm's are uniqued. If they are the same pointer, obviously they are
// the same, otherwise compare the fields.
if (L == R)
return 0;
if (int Res = cmpTypes(L->getFunctionType(), R->getFunctionType()))
return Res;
if (int Res = cmpMem(L->getAsmString(), R->getAsmString()))
return Res;
if (int Res = cmpMem(L->getConstraintString(), R->getConstraintString()))
return Res;
if (int Res = cmpNumbers(L->hasSideEffects(), R->hasSideEffects()))
return Res;
if (int Res = cmpNumbers(L->isAlignStack(), R->isAlignStack()))
return Res;
if (int Res = cmpNumbers(L->getDialect(), R->getDialect()))
return Res;
llvm_unreachable("InlineAsm blocks were not uniqued.");
return 0;
}
/// Compare two values used by the two functions under pair-wise comparison. If
/// this is the first time the values are seen, they're added to the mapping so
/// that we will detect mismatches on next use.
/// See comments in declaration for more details.
int FunctionComparator::cmpValues(const Value *L, const Value *R) const {
// Catch self-reference case.
if (L == FnL) {
if (R == FnR)
return 0;
return -1;
}
if (R == FnR) {
if (L == FnL)
return 0;
return 1;
}
const Constant *ConstL = dyn_cast<Constant>(L);
const Constant *ConstR = dyn_cast<Constant>(R);
if (ConstL && ConstR) {
if (L == R)
return 0;
return cmpConstants(ConstL, ConstR);
}
if (ConstL)
return 1;
if (ConstR)
return -1;
const InlineAsm *InlineAsmL = dyn_cast<InlineAsm>(L);
const InlineAsm *InlineAsmR = dyn_cast<InlineAsm>(R);
if (InlineAsmL && InlineAsmR)
return cmpInlineAsm(InlineAsmL, InlineAsmR);
if (InlineAsmL)
return 1;
if (InlineAsmR)
return -1;
auto LeftSN = sn_mapL.insert(std::make_pair(L, sn_mapL.size())),
RightSN = sn_mapR.insert(std::make_pair(R, sn_mapR.size()));
return cmpNumbers(LeftSN.first->second, RightSN.first->second);
}
// Test whether two basic blocks have equivalent behaviour.
int FunctionComparator::cmpBasicBlocks(const BasicBlock *BBL,
const BasicBlock *BBR) const {
BasicBlock::const_iterator InstL = BBL->begin(), InstLE = BBL->end();
BasicBlock::const_iterator InstR = BBR->begin(), InstRE = BBR->end();
do {
bool needToCmpOperands = true;
if (int Res = cmpOperations(&*InstL, &*InstR, needToCmpOperands))
return Res;
if (needToCmpOperands) {
assert(InstL->getNumOperands() == InstR->getNumOperands());
for (unsigned i = 0, e = InstL->getNumOperands(); i != e; ++i) {
Value *OpL = InstL->getOperand(i);
Value *OpR = InstR->getOperand(i);
if (int Res = cmpValues(OpL, OpR))
return Res;
// cmpValues should ensure this is true.
assert(cmpTypes(OpL->getType(), OpR->getType()) == 0);
}
}
++InstL;
++InstR;
} while (InstL != InstLE && InstR != InstRE);
if (InstL != InstLE && InstR == InstRE)
return 1;
if (InstL == InstLE && InstR != InstRE)
return -1;
return 0;
}
int FunctionComparator::compareSignature() const {
if (int Res = cmpAttrs(FnL->getAttributes(), FnR->getAttributes()))
return Res;
if (int Res = cmpNumbers(FnL->hasGC(), FnR->hasGC()))
return Res;
if (FnL->hasGC()) {
if (int Res = cmpMem(FnL->getGC(), FnR->getGC()))
return Res;
}
if (int Res = cmpNumbers(FnL->hasSection(), FnR->hasSection()))
return Res;
if (FnL->hasSection()) {
if (int Res = cmpMem(FnL->getSection(), FnR->getSection()))
return Res;
}
if (int Res = cmpNumbers(FnL->isVarArg(), FnR->isVarArg()))
return Res;
// TODO: if it's internal and only used in direct calls, we could handle this
// case too.
if (int Res = cmpNumbers(FnL->getCallingConv(), FnR->getCallingConv()))
return Res;
if (int Res = cmpTypes(FnL->getFunctionType(), FnR->getFunctionType()))
return Res;
assert(FnL->arg_size() == FnR->arg_size() &&
"Identically typed functions have different numbers of args!");
// Visit the arguments so that they get enumerated in the order they're
// passed in.
for (Function::const_arg_iterator ArgLI = FnL->arg_begin(),
ArgRI = FnR->arg_begin(),
ArgLE = FnL->arg_end();
ArgLI != ArgLE; ++ArgLI, ++ArgRI) {
if (cmpValues(&*ArgLI, &*ArgRI) != 0)
llvm_unreachable("Arguments repeat!");
}
return 0;
}
// Test whether the two functions have equivalent behaviour.
int FunctionComparator::compare() {
beginCompare();
if (int Res = compareSignature())
return Res;
// We do a CFG-ordered walk since the actual ordering of the blocks in the
// linked list is immaterial. Our walk starts at the entry block for both
// functions, then takes each block from each terminator in order. As an
// artifact, this also means that unreachable blocks are ignored.
SmallVector<const BasicBlock *, 8> FnLBBs, FnRBBs;
SmallPtrSet<const BasicBlock *, 32> VisitedBBs; // in terms of F1.
FnLBBs.push_back(&FnL->getEntryBlock());
FnRBBs.push_back(&FnR->getEntryBlock());
VisitedBBs.insert(FnLBBs[0]);
while (!FnLBBs.empty()) {
const BasicBlock *BBL = FnLBBs.pop_back_val();
const BasicBlock *BBR = FnRBBs.pop_back_val();
if (int Res = cmpValues(BBL, BBR))
return Res;
if (int Res = cmpBasicBlocks(BBL, BBR))
return Res;
const TerminatorInst *TermL = BBL->getTerminator();
const TerminatorInst *TermR = BBR->getTerminator();
assert(TermL->getNumSuccessors() == TermR->getNumSuccessors());
for (unsigned i = 0, e = TermL->getNumSuccessors(); i != e; ++i) {
if (!VisitedBBs.insert(TermL->getSuccessor(i)).second)
continue;
FnLBBs.push_back(TermL->getSuccessor(i));
FnRBBs.push_back(TermR->getSuccessor(i));
}
}
return 0;
}
namespace {
// Accumulate the hash of a sequence of 64-bit integers. This is similar to a
// hash of a sequence of 64bit ints, but the entire input does not need to be
// available at once. This interface is necessary for functionHash because it
// needs to accumulate the hash as the structure of the function is traversed
// without saving these values to an intermediate buffer. This form of hashing
// is not often needed, as usually the object to hash is just read from a
// buffer.
class HashAccumulator64 {
uint64_t Hash;
public:
// Initialize to random constant, so the state isn't zero.
HashAccumulator64() { Hash = 0x6acaa36bef8325c5ULL; }
void add(uint64_t V) {
Hash = llvm::hashing::detail::hash_16_bytes(Hash, V);
}
// No finishing is required, because the entire hash value is used.
uint64_t getHash() { return Hash; }
};
} // end anonymous namespace
// A function hash is calculated by considering only the number of arguments and
// whether a function is varargs, the order of basic blocks (given by the
// successors of each basic block in depth first order), and the order of
// opcodes of each instruction within each of these basic blocks. This mirrors
// the strategy compare() uses to compare functions by walking the BBs in depth
// first order and comparing each instruction in sequence. Because this hash
// does not look at the operands, it is insensitive to things such as the
// target of calls and the constants used in the function, which makes it useful
// when possibly merging functions which are the same modulo constants and call
// targets.
FunctionComparator::FunctionHash FunctionComparator::functionHash(Function &F) {
HashAccumulator64 H;
H.add(F.isVarArg());
H.add(F.arg_size());
SmallVector<const BasicBlock *, 8> BBs;
SmallSet<const BasicBlock *, 16> VisitedBBs;
// Walk the blocks in the same order as FunctionComparator::cmpBasicBlocks(),
// accumulating the hash of the function "structure." (BB and opcode sequence)
BBs.push_back(&F.getEntryBlock());
VisitedBBs.insert(BBs[0]);
while (!BBs.empty()) {
const BasicBlock *BB = BBs.pop_back_val();
// This random value acts as a block header, as otherwise the partition of
// opcodes into BBs wouldn't affect the hash, only the order of the opcodes
H.add(45798);
for (auto &Inst : *BB) {
H.add(Inst.getOpcode());
}
const TerminatorInst *Term = BB->getTerminator();
for (unsigned i = 0, e = Term->getNumSuccessors(); i != e; ++i) {
if (!VisitedBBs.insert(Term->getSuccessor(i)).second)
continue;
BBs.push_back(Term->getSuccessor(i));
}
}
return H.getHash();
}

1
unittests/Transforms/Utils/CMakeLists.txt
View File

@ -8,6 +8,7 @@ set(LLVM_LINK_COMPONENTS
add_llvm_unittest(UtilsTests
ASanStackFrameLayoutTest.cpp
Cloning.cpp
FunctionComparator.cpp
IntegerDivision.cpp
Local.cpp
MemorySSA.cpp

130
unittests/Transforms/Utils/FunctionComparator.cpp Normal file
View File

@ -0,0 +1,130 @@
//===- FunctionComparator.cpp - Unit tests for FunctionComparator ---------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "llvm/Transforms/Utils/FunctionComparator.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/LLVMContext.h"
#include "gtest/gtest.h"
using namespace llvm;
/// Generates a simple test function.
struct TestFunction {
Function *F;
BasicBlock *BB;
Constant *C;
Instruction *I;
Type *T;
TestFunction(LLVMContext &Ctx, Module &M, int addVal) {
IRBuilder<> B(Ctx);
T = B.getInt8Ty();
F = Function::Create(FunctionType::get(T, {B.getInt8PtrTy()}, false),
GlobalValue::ExternalLinkage, "F", &M);
BB = BasicBlock::Create(Ctx, "", F);
B.SetInsertPoint(BB);
Argument *PointerArg = &*F->arg_begin();
LoadInst *LoadInst = B.CreateLoad(PointerArg);
C = B.getInt8(addVal);
I = cast<Instruction>(B.CreateAdd(LoadInst, C));
B.CreateRet(I);
}
};
/// A class for testing the FunctionComparator API.
///
/// The main purpose is to test if the required protected functions are
/// accessible from a derived class of FunctionComparator.
class TestComparator : public FunctionComparator {
public:
TestComparator(const Function *F1, const Function *F2,
GlobalNumberState *GN)
: FunctionComparator(F1, F2, GN) {
}
bool testFunctionAccess(const Function *F1, const Function *F2) {
// Test if FnL and FnR are accessible.
return F1 == FnL && F2 == FnR;
}
int testCompare() {
return compare();
}
int testCompareSignature() {
beginCompare();
return compareSignature();
}
int testCmpBasicBlocks(BasicBlock *BBL, BasicBlock *BBR) {
beginCompare();
return cmpBasicBlocks(BBL, BBR);
}
int testCmpConstants(const Constant *L, const Constant *R) {
beginCompare();
return cmpConstants(L, R);
}
int testCmpGlobalValues(GlobalValue *L, GlobalValue *R) {
beginCompare();
return cmpGlobalValues(L, R);
}
int testCmpValues(const Value *L, const Value *R) {
beginCompare();
return cmpValues(L, R);
}
int testCmpOperations(const Instruction *L, const Instruction *R,
bool &needToCmpOperands) {
beginCompare();
return cmpOperations(L, R, needToCmpOperands);
}
int testCmpTypes(Type *TyL, Type *TyR) {
beginCompare();
return cmpTypes(TyL, TyR);
}
int testCmpPrimitives() {
beginCompare();
return
cmpNumbers(2, 3) +
cmpAPInts(APInt(32, 2), APInt(32, 3)) +
cmpAPFloats(APFloat(2.0), APFloat(3.0)) +
cmpMem("2", "3");
}
};
/// A sanity check for the FunctionComparator API.
TEST(FunctionComparatorTest, TestAPI) {
LLVMContext C;
Module M("test", C);
TestFunction F1(C, M, 27);
TestFunction F2(C, M, 28);
GlobalNumberState GN;
TestComparator Cmp(F1.F, F2.F, &GN);
EXPECT_TRUE(Cmp.testFunctionAccess(F1.F, F2.F));
EXPECT_EQ(Cmp.testCompare(), -1);
EXPECT_EQ(Cmp.testCompareSignature(), 0);
EXPECT_EQ(Cmp.testCmpBasicBlocks(F1.BB, F2.BB), -1);
EXPECT_EQ(Cmp.testCmpConstants(F1.C, F2.C), -1);
EXPECT_EQ(Cmp.testCmpGlobalValues(F1.F, F2.F), -1);
EXPECT_EQ(Cmp.testCmpValues(F1.I, F2.I), 0);
bool needToCmpOperands = false;
EXPECT_EQ(Cmp.testCmpOperations(F1.I, F2.I, needToCmpOperands), 0);
EXPECT_TRUE(needToCmpOperands);
EXPECT_EQ(Cmp.testCmpTypes(F1.T, F2.T), 0);
EXPECT_EQ(Cmp.testCmpPrimitives(), -4);
}