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//===--------------- IRCanonicalizer.cpp - IR Canonicalizer ---------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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/// \file
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/// This file implements the IRCanonicalizer class which aims to transform LLVM
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/// Modules into a canonical form by reordering and renaming instructions while
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/// preserving the same semantics. The canonicalizer makes it easier to spot
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/// semantic differences while diffing two modules which have undergone
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/// different passes.
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///
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//===----------------------------------------------------------------------===//
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#include "llvm/ADT/SetVector.h"
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#include "llvm/ADT/SmallPtrSet.h"
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#include "llvm/ADT/SmallVector.h"
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#include "llvm/IR/BasicBlock.h"
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#include "llvm/IR/Function.h"
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#include "llvm/IR/IRBuilder.h"
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#include "llvm/IR/InstIterator.h"
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#include "llvm/IR/Module.h"
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#include "llvm/InitializePasses.h"
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#include "llvm/Pass.h"
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#include "llvm/PassRegistry.h"
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#include "llvm/Support/CommandLine.h"
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#include "llvm/Transforms/Utils.h"
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#include <algorithm>
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#include <vector>
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#define DEBUG_TYPE "ir-canonicalizer"
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using namespace llvm;
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namespace {
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/// IRCanonicalizer aims to transform LLVM IR into canonical form.
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class IRCanonicalizer : public FunctionPass {
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public:
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static char ID;
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/// \name Canonicalizer flags.
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/// @{
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/// Preserves original order of instructions.
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static cl::opt<bool> PreserveOrder;
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/// Renames all instructions (including user-named).
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static cl::opt<bool> RenameAll;
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/// Folds all regular instructions (including pre-outputs).
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static cl::opt<bool> FoldPreoutputs;
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/// Sorts and reorders operands in commutative instructions.
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static cl::opt<bool> ReorderOperands;
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/// @}
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/// Constructor for the IRCanonicalizer.
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IRCanonicalizer() : FunctionPass(ID) {
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initializeIRCanonicalizerPass(*PassRegistry::getPassRegistry());
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}
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bool runOnFunction(Function &F) override;
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private:
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// Random constant for hashing, so the state isn't zero.
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const uint64_t MagicHashConstant = 0x6acaa36bef8325c5ULL;
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/// \name Naming.
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/// @{
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void nameFunctionArguments(Function &F);
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void nameBasicBlocks(Function &F);
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void nameInstruction(Instruction *I);
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void nameAsInitialInstruction(Instruction *I);
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void nameAsRegularInstruction(Instruction *I);
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void foldInstructionName(Instruction *I);
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/// @}
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/// \name Reordering.
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/// @{
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void reorderInstructions(SmallVector<Instruction *, 16> &Outputs);
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void reorderInstruction(Instruction *Used, Instruction *User,
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SmallPtrSet<const Instruction *, 32> &Visited);
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void reorderInstructionOperandsByNames(Instruction *I);
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void reorderPHIIncomingValues(PHINode *PN);
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/// @}
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/// \name Utility methods.
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/// @{
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SmallVector<Instruction *, 16> collectOutputInstructions(Function &F);
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bool isOutput(const Instruction *I);
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bool isInitialInstruction(const Instruction *I);
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bool hasOnlyImmediateOperands(const Instruction *I);
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SetVector<int>
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getOutputFootprint(Instruction *I,
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SmallPtrSet<const Instruction *, 32> &Visited);
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/// @}
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};
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} // namespace
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char IRCanonicalizer::ID = 0;
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cl::opt<bool> IRCanonicalizer::PreserveOrder(
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"preserve-order", cl::Hidden,
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cl::desc("Preserves original instruction order"));
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cl::opt<bool> IRCanonicalizer::RenameAll(
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"rename-all", cl::Hidden,
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cl::desc("Renames all instructions (including user-named)"));
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cl::opt<bool> IRCanonicalizer::FoldPreoutputs(
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"fold-all", cl::Hidden,
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cl::desc("Folds all regular instructions (including pre-outputs)"));
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cl::opt<bool> IRCanonicalizer::ReorderOperands(
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"reorder-operands", cl::Hidden,
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cl::desc("Sorts and reorders operands in commutative instructions"));
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INITIALIZE_PASS(IRCanonicalizer, "ir-canonicalizer",
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"Transforms IR into canonical form", false, false)
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Pass *llvm::createIRCanonicalizerPass() { return new IRCanonicalizer(); }
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/// Entry method to the IRCanonicalizer.
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///
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/// \param M Module to canonicalize.
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bool IRCanonicalizer::runOnFunction(Function &F) {
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nameFunctionArguments(F);
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nameBasicBlocks(F);
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SmallVector<Instruction *, 16> Outputs = collectOutputInstructions(F);
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if (!PreserveOrder)
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reorderInstructions(Outputs);
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for (auto &I : Outputs)
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nameInstruction(I);
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for (auto &I : instructions(F)) {
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if (!PreserveOrder) {
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if (ReorderOperands && I.isCommutative())
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reorderInstructionOperandsByNames(&I);
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if (auto *PN = dyn_cast<PHINode>(&I))
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reorderPHIIncomingValues(PN);
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}
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foldInstructionName(&I);
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}
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return true;
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}
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/// Numbers arguments.
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///
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/// \param F Function whose arguments will be renamed.
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void IRCanonicalizer::nameFunctionArguments(Function &F) {
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int ArgumentCounter = 0;
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for (auto &A : F.args()) {
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if (RenameAll || A.getName().empty()) {
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A.setName("a" + Twine(ArgumentCounter));
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++ArgumentCounter;
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}
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}
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}
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/// Names basic blocks using a generated hash for each basic block in
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/// a function considering the opcode and the order of output instructions.
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///
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/// \param F Function containing basic blocks to rename.
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void IRCanonicalizer::nameBasicBlocks(Function &F) {
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for (auto &B : F) {
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// Initialize to a magic constant, so the state isn't zero.
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uint64_t Hash = MagicHashConstant;
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// Hash considering output instruction opcodes.
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for (auto &I : B)
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if (isOutput(&I))
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Hash = hashing::detail::hash_16_bytes(Hash, I.getOpcode());
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if (RenameAll || B.getName().empty()) {
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// Name basic block. Substring hash to make diffs more readable.
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B.setName("bb" + std::to_string(Hash).substr(0, 5));
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}
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}
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}
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/// Names instructions graphically (recursive) in accordance with the
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/// def-use tree, starting from the initial instructions (defs), finishing at
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/// the output (top-most user) instructions (depth-first).
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///
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/// \param I Instruction to be renamed.
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void IRCanonicalizer::nameInstruction(Instruction *I) {
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// Determine the type of instruction to name.
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if (isInitialInstruction(I)) {
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// This is an initial instruction.
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nameAsInitialInstruction(I);
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} else {
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// This must be a regular instruction.
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nameAsRegularInstruction(I);
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}
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}
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/// Names instruction following the scheme:
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/// vl00000Callee(Operands)
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///
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/// Where 00000 is a hash calculated considering instruction's opcode and output
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/// footprint. Callee's name is only included when instruction's type is
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/// CallInst. In cases where instruction is commutative, operands list is also
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/// sorted.
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///
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/// Renames instruction only when RenameAll flag is raised or instruction is
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/// unnamed.
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///
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/// \see getOutputFootprint()
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/// \param I Instruction to be renamed.
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void IRCanonicalizer::nameAsInitialInstruction(Instruction *I) {
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if (I->getType()->isVoidTy() || (!I->getName().empty() && !RenameAll))
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return;
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// Instruction operands for further sorting.
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SmallVector<SmallString<64>, 4> Operands;
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// Collect operands.
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for (auto &OP : I->operands()) {
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if (!isa<Function>(OP)) {
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std::string TextRepresentation;
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raw_string_ostream Stream(TextRepresentation);
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OP->printAsOperand(Stream, false);
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Operands.push_back(StringRef(Stream.str()));
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}
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}
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if (I->isCommutative())
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llvm::sort(Operands);
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// Initialize to a magic constant, so the state isn't zero.
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uint64_t Hash = MagicHashConstant;
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// Consider instruction's opcode in the hash.
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Hash = hashing::detail::hash_16_bytes(Hash, I->getOpcode());
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SmallPtrSet<const Instruction *, 32> Visited;
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// Get output footprint for I.
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SetVector<int> OutputFootprint = getOutputFootprint(I, Visited);
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// Consider output footprint in the hash.
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for (const int &Output : OutputFootprint)
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Hash = hashing::detail::hash_16_bytes(Hash, Output);
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// Base instruction name.
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SmallString<256> Name;
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Name.append("vl" + std::to_string(Hash).substr(0, 5));
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// In case of CallInst, consider callee in the instruction name.
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if (const auto *CI = dyn_cast<CallInst>(I)) {
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Function *F = CI->getCalledFunction();
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if (F != nullptr) {
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Name.append(F->getName());
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}
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}
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Name.append("(");
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for (unsigned long i = 0; i < Operands.size(); ++i) {
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Name.append(Operands[i]);
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if (i < Operands.size() - 1)
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Name.append(", ");
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}
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Name.append(")");
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I->setName(Name);
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}
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/// Names instruction following the scheme:
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/// op00000Callee(Operands)
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///
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/// Where 00000 is a hash calculated considering instruction's opcode, its
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/// operands' opcodes and order. Callee's name is only included when
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/// instruction's type is CallInst. In cases where instruction is commutative,
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/// operand list is also sorted.
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///
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/// Names instructions recursively in accordance with the def-use tree,
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/// starting from the initial instructions (defs), finishing at
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/// the output (top-most user) instructions (depth-first).
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///
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/// Renames instruction only when RenameAll flag is raised or instruction is
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/// unnamed.
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///
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/// \see getOutputFootprint()
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/// \param I Instruction to be renamed.
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void IRCanonicalizer::nameAsRegularInstruction(Instruction *I) {
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// Instruction operands for further sorting.
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SmallVector<SmallString<128>, 4> Operands;
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// The name of a regular instruction depends
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// on the names of its operands. Hence, all
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// operands must be named first in the use-def
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// walk.
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// Collect operands.
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for (auto &OP : I->operands()) {
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if (auto *IOP = dyn_cast<Instruction>(OP)) {
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// Walk down the use-def chain.
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nameInstruction(IOP);
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Operands.push_back(IOP->getName());
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} else if (isa<Value>(OP) && !isa<Function>(OP)) {
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// This must be an immediate value.
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std::string TextRepresentation;
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raw_string_ostream Stream(TextRepresentation);
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OP->printAsOperand(Stream, false);
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Operands.push_back(StringRef(Stream.str()));
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}
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}
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if (I->isCommutative())
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llvm::sort(Operands.begin(), Operands.end());
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// Initialize to a magic constant, so the state isn't zero.
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uint64_t Hash = MagicHashConstant;
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// Consider instruction opcode in the hash.
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Hash = hashing::detail::hash_16_bytes(Hash, I->getOpcode());
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// Operand opcodes for further sorting (commutative).
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SmallVector<int, 4> OperandsOpcodes;
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// Collect operand opcodes for hashing.
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for (auto &OP : I->operands())
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if (auto *IOP = dyn_cast<Instruction>(OP))
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OperandsOpcodes.push_back(IOP->getOpcode());
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if (I->isCommutative())
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llvm::sort(OperandsOpcodes.begin(), OperandsOpcodes.end());
|
|
|
|
|
|
|
|
|
|
// Consider operand opcodes in the hash.
|
|
|
|
|
for (const int Code : OperandsOpcodes)
|
|
|
|
|
Hash = hashing::detail::hash_16_bytes(Hash, Code);
|
|
|
|
|
|
|
|
|
|
// Base instruction name.
|
|
|
|
|
SmallString<512> Name;
|
|
|
|
|
Name.append("op" + std::to_string(Hash).substr(0, 5));
|
|
|
|
|
|
|
|
|
|
// In case of CallInst, consider callee in the instruction name.
|
|
|
|
|
if (const auto *CI = dyn_cast<CallInst>(I))
|
|
|
|
|
if (const Function *F = CI->getCalledFunction())
|
|
|
|
|
Name.append(F->getName());
|
|
|
|
|
|
|
|
|
|
Name.append("(");
|
|
|
|
|
for (unsigned long i = 0; i < Operands.size(); ++i) {
|
|
|
|
|
Name.append(Operands[i]);
|
|
|
|
|
|
|
|
|
|
if (i < Operands.size() - 1)
|
|
|
|
|
Name.append(", ");
|
|
|
|
|
}
|
|
|
|
|
Name.append(")");
|
|
|
|
|
|
|
|
|
|
if ((I->getName().empty() || RenameAll) && !I->getType()->isVoidTy())
|
|
|
|
|
I->setName(Name);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/// Shortens instruction's name. This method removes called function name from
|
|
|
|
|
/// the instruction name and substitutes the call chain with a corresponding
|
|
|
|
|
/// list of operands.
|
|
|
|
|
///
|
|
|
|
|
/// Examples:
|
|
|
|
|
/// op00000Callee(op00001Callee(...), vl00000Callee(1, 2), ...) ->
|
|
|
|
|
/// op00000(op00001, vl00000, ...) vl00000Callee(1, 2) -> vl00000(1, 2)
|
|
|
|
|
///
|
|
|
|
|
/// This method omits output instructions and pre-output (instructions directly
|
|
|
|
|
/// used by an output instruction) instructions (by default). By default it also
|
|
|
|
|
/// does not affect user named instructions.
|
|
|
|
|
///
|
|
|
|
|
/// \param I Instruction whose name will be folded.
|
|
|
|
|
void IRCanonicalizer::foldInstructionName(Instruction *I) {
|
|
|
|
|
// If this flag is raised, fold all regular
|
|
|
|
|
// instructions (including pre-outputs).
|
|
|
|
|
if (!FoldPreoutputs) {
|
|
|
|
|
// Don't fold if one of the users is an output instruction.
|
|
|
|
|
for (auto *U : I->users())
|
|
|
|
|
if (auto *IU = dyn_cast<Instruction>(U))
|
|
|
|
|
if (isOutput(IU))
|
|
|
|
|
return;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
// Don't fold if it is an output instruction or has no op prefix.
|
|
|
|
|
if (isOutput(I) || I->getName().substr(0, 2) != "op")
|
|
|
|
|
return;
|
|
|
|
|
|
|
|
|
|
// Instruction operands.
|
|
|
|
|
SmallVector<SmallString<64>, 4> Operands;
|
|
|
|
|
|
|
|
|
|
for (auto &OP : I->operands()) {
|
|
|
|
|
if (const Instruction *IOP = dyn_cast<Instruction>(OP)) {
|
|
|
|
|
bool HasCanonicalName = I->getName().substr(0, 2) == "op" ||
|
|
|
|
|
I->getName().substr(0, 2) == "vl";
|
|
|
|
|
|
|
|
|
|
Operands.push_back(HasCanonicalName ? IOP->getName().substr(0, 7)
|
|
|
|
|
: IOP->getName());
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
if (I->isCommutative())
|
|
|
|
|
llvm::sort(Operands.begin(), Operands.end());
|
|
|
|
|
|
|
|
|
|
SmallString<256> Name;
|
|
|
|
|
Name.append(I->getName().substr(0, 7));
|
|
|
|
|
|
|
|
|
|
Name.append("(");
|
|
|
|
|
for (unsigned long i = 0; i < Operands.size(); ++i) {
|
|
|
|
|
Name.append(Operands[i]);
|
|
|
|
|
|
|
|
|
|
if (i < Operands.size() - 1)
|
|
|
|
|
Name.append(", ");
|
|
|
|
|
}
|
|
|
|
|
Name.append(")");
|
|
|
|
|
|
|
|
|
|
I->setName(Name);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/// Reorders instructions by walking up the tree from each operand of an output
|
|
|
|
|
/// instruction and reducing the def-use distance.
|
|
|
|
|
/// This method assumes that output instructions were collected top-down,
|
|
|
|
|
/// otherwise the def-use chain may be broken.
|
|
|
|
|
/// This method is a wrapper for recursive reorderInstruction().
|
|
|
|
|
///
|
|
|
|
|
/// \see reorderInstruction()
|
|
|
|
|
/// \param Outputs Vector of pointers to output instructions collected top-down.
|
|
|
|
|
void IRCanonicalizer::reorderInstructions(
|
|
|
|
|
SmallVector<Instruction *, 16> &Outputs) {
|
|
|
|
|
// This method assumes output instructions were collected top-down,
|
|
|
|
|
// otherwise the def-use chain may be broken.
|
|
|
|
|
|
|
|
|
|
SmallPtrSet<const Instruction *, 32> Visited;
|
|
|
|
|
|
|
|
|
|
// Walk up the tree.
|
|
|
|
|
for (auto &I : Outputs)
|
|
|
|
|
for (auto &OP : I->operands())
|
|
|
|
|
if (auto *IOP = dyn_cast<Instruction>(OP))
|
|
|
|
|
reorderInstruction(IOP, I, Visited);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/// Reduces def-use distance or places instruction at the end of the basic
|
|
|
|
|
/// block. Continues to walk up the def-use tree recursively. Used by
|
|
|
|
|
/// reorderInstructions().
|
|
|
|
|
///
|
|
|
|
|
/// \see reorderInstructions()
|
|
|
|
|
/// \param Used Pointer to the instruction whose value is used by the \p User.
|
|
|
|
|
/// \param User Pointer to the instruction which uses the \p Used.
|
|
|
|
|
/// \param Visited Set of visited instructions.
|
|
|
|
|
void IRCanonicalizer::reorderInstruction(
|
|
|
|
|
Instruction *Used, Instruction *User,
|
|
|
|
|
SmallPtrSet<const Instruction *, 32> &Visited) {
|
|
|
|
|
|
|
|
|
|
if (!Visited.count(Used)) {
|
|
|
|
|
Visited.insert(Used);
|
|
|
|
|
|
|
|
|
|
if (Used->getParent() == User->getParent()) {
|
|
|
|
|
// If Used and User share the same basic block move Used just before User.
|
|
|
|
|
Used->moveBefore(User);
|
|
|
|
|
} else {
|
|
|
|
|
// Otherwise move Used to the very end of its basic block.
|
|
|
|
|
Used->moveBefore(&Used->getParent()->back());
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
for (auto &OP : Used->operands()) {
|
|
|
|
|
if (auto *IOP = dyn_cast<Instruction>(OP)) {
|
|
|
|
|
// Walk up the def-use tree.
|
|
|
|
|
reorderInstruction(IOP, Used, Visited);
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/// Reorders instruction's operands alphabetically. This method assumes
|
|
|
|
|
/// that passed instruction is commutative. Changing the operand order
|
|
|
|
|
/// in other instructions may change the semantics.
|
|
|
|
|
///
|
|
|
|
|
/// \param I Instruction whose operands will be reordered.
|
|
|
|
|
void IRCanonicalizer::reorderInstructionOperandsByNames(Instruction *I) {
|
|
|
|
|
// This method assumes that passed I is commutative,
|
|
|
|
|
// changing the order of operands in other instructions
|
|
|
|
|
// may change the semantics.
|
|
|
|
|
|
|
|
|
|
// Instruction operands for further sorting.
|
|
|
|
|
SmallVector<std::pair<std::string, Value *>, 4> Operands;
|
|
|
|
|
|
|
|
|
|
// Collect operands.
|
|
|
|
|
for (auto &OP : I->operands()) {
|
|
|
|
|
if (auto *VOP = dyn_cast<Value>(OP)) {
|
|
|
|
|
if (isa<Instruction>(VOP)) {
|
|
|
|
|
// This is an an instruction.
|
|
|
|
|
Operands.push_back(
|
|
|
|
|
std::pair<std::string, Value *>(VOP->getName(), VOP));
|
|
|
|
|
} else {
|
|
|
|
|
std::string TextRepresentation;
|
|
|
|
|
raw_string_ostream Stream(TextRepresentation);
|
|
|
|
|
OP->printAsOperand(Stream, false);
|
|
|
|
|
Operands.push_back(std::pair<std::string, Value *>(Stream.str(), VOP));
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
// Sort operands.
|
|
|
|
|
llvm::sort(Operands.begin(), Operands.end(), llvm::less_first());
|
|
|
|
|
|
|
|
|
|
// Reorder operands.
|
|
|
|
|
unsigned Position = 0;
|
|
|
|
|
for (auto &OP : I->operands()) {
|
|
|
|
|
OP.set(Operands[Position].second);
|
|
|
|
|
Position++;
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/// Reorders PHI node's values according to the names of corresponding basic
|
|
|
|
|
/// blocks.
|
|
|
|
|
///
|
|
|
|
|
/// \param PN PHI node to canonicalize.
|
|
|
|
|
void IRCanonicalizer::reorderPHIIncomingValues(PHINode *PN) {
|
|
|
|
|
// Values for further sorting.
|
|
|
|
|
SmallVector<std::pair<Value *, BasicBlock *>, 2> Values;
|
|
|
|
|
|
|
|
|
|
// Collect blocks and corresponding values.
|
|
|
|
|
for (auto &BB : PN->blocks()) {
|
|
|
|
|
Value *V = PN->getIncomingValueForBlock(BB);
|
|
|
|
|
Values.push_back(std::pair<Value *, BasicBlock *>(V, BB));
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
// Sort values according to the name of a basic block.
|
|
|
|
|
llvm::sort(Values, [](const std::pair<Value *, BasicBlock *> &LHS,
|
|
|
|
|
const std::pair<Value *, BasicBlock *> &RHS) {
|
|
|
|
|
return LHS.second->getName() < RHS.second->getName();
|
|
|
|
|
});
|
|
|
|
|
|
|
|
|
|
// Swap.
|
|
|
|
|
for (unsigned i = 0; i < Values.size(); ++i) {
|
|
|
|
|
PN->setIncomingBlock(i, Values[i].second);
|
|
|
|
|
PN->setIncomingValue(i, Values[i].first);
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/// Returns a vector of output instructions. An output is an instruction which
|
|
|
|
|
/// has side-effects or is ReturnInst. Uses isOutput().
|
|
|
|
|
///
|
|
|
|
|
/// \see isOutput()
|
|
|
|
|
/// \param F Function to collect outputs from.
|
|
|
|
|
SmallVector<Instruction *, 16>
|
|
|
|
|
IRCanonicalizer::collectOutputInstructions(Function &F) {
|
|
|
|
|
// Output instructions are collected top-down in each function,
|
|
|
|
|
// any change may break the def-use chain in reordering methods.
|
|
|
|
|
SmallVector<Instruction *, 16> Outputs;
|
|
|
|
|
|
|
|
|
|
for (auto &I : instructions(F))
|
|
|
|
|
if (isOutput(&I))
|
|
|
|
|
Outputs.push_back(&I);
|
|
|
|
|
|
|
|
|
|
return Outputs;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/// Helper method checking whether the instruction may have side effects or is
|
|
|
|
|
/// ReturnInst.
|
|
|
|
|
///
|
|
|
|
|
/// \param I Considered instruction.
|
|
|
|
|
bool IRCanonicalizer::isOutput(const Instruction *I) {
|
|
|
|
|
// Outputs are such instructions which may have side effects or is ReturnInst.
|
|
|
|
|
if (I->mayHaveSideEffects() || isa<ReturnInst>(I))
|
|
|
|
|
return true;
|
|
|
|
|
|
|
|
|
|
return false;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/// Helper method checking whether the instruction has users and only
|
|
|
|
|
/// immediate operands.
|
|
|
|
|
///
|
|
|
|
|
/// \param I Considered instruction.
|
|
|
|
|
bool IRCanonicalizer::isInitialInstruction(const Instruction *I) {
|
|
|
|
|
// Initial instructions are such instructions whose values are used by
|
|
|
|
|
// other instructions, yet they only depend on immediate values.
|
|
|
|
|
return !I->user_empty() && hasOnlyImmediateOperands(I);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/// Helper method checking whether the instruction has only immediate operands.
|
|
|
|
|
///
|
|
|
|
|
/// \param I Considered instruction.
|
|
|
|
|
bool IRCanonicalizer::hasOnlyImmediateOperands(const Instruction *I) {
|
|
|
|
|
for (const auto &OP : I->operands())
|
|
|
|
|
if (isa<Instruction>(OP))
|
|
|
|
|
return false; // Found non-immediate operand (instruction).
|
|
|
|
|
|
|
|
|
|
return true;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/// Helper method returning indices (distance from the beginning of the basic
|
|
|
|
|
/// block) of outputs using the \p I (eliminates repetitions). Walks down the
|
|
|
|
|
/// def-use tree recursively.
|
|
|
|
|
///
|
|
|
|
|
/// \param I Considered instruction.
|
|
|
|
|
/// \param Visited Set of visited instructions.
|
|
|
|
|
SetVector<int> IRCanonicalizer::getOutputFootprint(
|
|
|
|
|
Instruction *I, SmallPtrSet<const Instruction *, 32> &Visited) {
|
|
|
|
|
|
|
|
|
|
// Vector containing indexes of outputs (no repetitions),
|
|
|
|
|
// which use I in the order of walking down the def-use tree.
|
|
|
|
|
SetVector<int> Outputs;
|
|
|
|
|
|
|
|
|
|
if (!Visited.count(I)) {
|
|
|
|
|
Visited.insert(I);
|
|
|
|
|
|
|
|
|
|
if (isOutput(I)) {
|
|
|
|
|
// Gets output instruction's parent function.
|
|
|
|
|
Function *Func = I->getParent()->getParent();
|
|
|
|
|
|
|
|
|
|
// Finds and inserts the index of the output to the vector.
|
|
|
|
|
unsigned Count = 0;
|
|
|
|
|
for (const auto &B : *Func) {
|
|
|
|
|
for (const auto &E : B) {
|
|
|
|
|
if (&E == I)
|
|
|
|
|
Outputs.insert(Count);
|
|
|
|
|
Count++;
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
// Returns to the used instruction.
|
|
|
|
|
return Outputs;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
for (auto *U : I->users()) {
|
|
|
|
|
if (auto *UI = dyn_cast<Instruction>(U)) {
|
|
|
|
|
// Vector for outputs which use UI.
|
|
|
|
|
SetVector<int> OutputsUsingUI = getOutputFootprint(UI, Visited);
|
|
|
|
|
|
|
|
|
|
// Insert the indexes of outputs using UI.
|
|
|
|
|
Outputs.insert(OutputsUsingUI.begin(), OutputsUsingUI.end());
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
// Return to the used instruction.
|
|
|
|
|
return Outputs;
|
|
|
|
|
}
|