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-rw-r--r--llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp21
-rw-r--r--llvm/lib/CodeGen/CMakeLists.txt1
-rw-r--r--llvm/lib/CodeGen/MachineBlockHashInfo.cpp115
-rw-r--r--llvm/lib/CodeGen/TargetPassConfig.cpp8
4 files changed, 139 insertions, 6 deletions
diff --git a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index fefde64f..8aa488f 100644
--- a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -41,6 +41,7 @@
#include "llvm/CodeGen/GCMetadataPrinter.h"
#include "llvm/CodeGen/LazyMachineBlockFrequencyInfo.h"
#include "llvm/CodeGen/MachineBasicBlock.h"
+#include "llvm/CodeGen/MachineBlockHashInfo.h"
#include "llvm/CodeGen/MachineBranchProbabilityInfo.h"
#include "llvm/CodeGen/MachineConstantPool.h"
#include "llvm/CodeGen/MachineDominators.h"
@@ -184,6 +185,8 @@ static cl::opt<bool> PrintLatency(
cl::desc("Print instruction latencies as verbose asm comments"), cl::Hidden,
cl::init(false));
+extern cl::opt<bool> EmitBBHash;
+
STATISTIC(EmittedInsts, "Number of machine instrs printed");
char AsmPrinter::ID = 0;
@@ -474,6 +477,8 @@ void AsmPrinter::getAnalysisUsage(AnalysisUsage &AU) const {
AU.addRequired<GCModuleInfo>();
AU.addRequired<LazyMachineBlockFrequencyInfoPass>();
AU.addRequired<MachineBranchProbabilityInfoWrapperPass>();
+ if (EmitBBHash)
+ AU.addRequired<MachineBlockHashInfo>();
}
bool AsmPrinter::doInitialization(Module &M) {
@@ -1434,14 +1439,11 @@ getBBAddrMapFeature(const MachineFunction &MF, int NumMBBSectionRanges,
"BB entries info is required for BBFreq and BrProb "
"features");
}
- return {FuncEntryCountEnabled,
- BBFreqEnabled,
- BrProbEnabled,
+ return {FuncEntryCountEnabled, BBFreqEnabled, BrProbEnabled,
MF.hasBBSections() && NumMBBSectionRanges > 1,
// Use static_cast to avoid breakage of tests on windows.
- static_cast<bool>(BBAddrMapSkipEmitBBEntries),
- HasCalls,
- false};
+ static_cast<bool>(BBAddrMapSkipEmitBBEntries), HasCalls,
+ static_cast<bool>(EmitBBHash)};
}
void AsmPrinter::emitBBAddrMapSection(const MachineFunction &MF) {
@@ -1500,6 +1502,9 @@ void AsmPrinter::emitBBAddrMapSection(const MachineFunction &MF) {
PrevMBBEndSymbol = MBBSymbol;
}
+ auto MBHI =
+ Features.BBHash ? &getAnalysis<MachineBlockHashInfo>() : nullptr;
+
if (!Features.OmitBBEntries) {
OutStreamer->AddComment("BB id");
// Emit the BB ID for this basic block.
@@ -1527,6 +1532,10 @@ void AsmPrinter::emitBBAddrMapSection(const MachineFunction &MF) {
emitLabelDifferenceAsULEB128(MBB.getEndSymbol(), CurrentLabel);
// Emit the Metadata.
OutStreamer->emitULEB128IntValue(getBBAddrMapMetadata(MBB));
+ // Emit the Hash.
+ if (MBHI) {
+ OutStreamer->emitInt64(MBHI->getMBBHash(MBB));
+ }
}
PrevMBBEndSymbol = MBB.getEndSymbol();
}
diff --git a/llvm/lib/CodeGen/CMakeLists.txt b/llvm/lib/CodeGen/CMakeLists.txt
index b6872605..4373c53 100644
--- a/llvm/lib/CodeGen/CMakeLists.txt
+++ b/llvm/lib/CodeGen/CMakeLists.txt
@@ -108,6 +108,7 @@ add_llvm_component_library(LLVMCodeGen
LowerEmuTLS.cpp
MachineBasicBlock.cpp
MachineBlockFrequencyInfo.cpp
+ MachineBlockHashInfo.cpp
MachineBlockPlacement.cpp
MachineBranchProbabilityInfo.cpp
MachineCFGPrinter.cpp
diff --git a/llvm/lib/CodeGen/MachineBlockHashInfo.cpp b/llvm/lib/CodeGen/MachineBlockHashInfo.cpp
new file mode 100644
index 0000000..c4d9c0f
--- /dev/null
+++ b/llvm/lib/CodeGen/MachineBlockHashInfo.cpp
@@ -0,0 +1,115 @@
+//===- llvm/CodeGen/MachineBlockHashInfo.cpp---------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// Compute the hashes of basic blocks.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/CodeGen/MachineBlockHashInfo.h"
+#include "llvm/CodeGen/Passes.h"
+#include "llvm/InitializePasses.h"
+#include "llvm/Target/TargetMachine.h"
+
+using namespace llvm;
+
+uint64_t hashBlock(const MachineBasicBlock &MBB, bool HashOperands) {
+ uint64_t Hash = 0;
+ for (const MachineInstr &MI : MBB) {
+ if (MI.isMetaInstruction() || MI.isTerminator())
+ continue;
+ Hash = hashing::detail::hash_16_bytes(Hash, MI.getOpcode());
+ if (HashOperands) {
+ for (unsigned i = 0; i < MI.getNumOperands(); i++) {
+ Hash =
+ hashing::detail::hash_16_bytes(Hash, hash_value(MI.getOperand(i)));
+ }
+ }
+ }
+ return Hash;
+}
+
+/// Fold a 64-bit integer to a 16-bit one.
+uint16_t fold_64_to_16(const uint64_t Value) {
+ uint16_t Res = static_cast<uint16_t>(Value);
+ Res ^= static_cast<uint16_t>(Value >> 16);
+ Res ^= static_cast<uint16_t>(Value >> 32);
+ Res ^= static_cast<uint16_t>(Value >> 48);
+ return Res;
+}
+
+INITIALIZE_PASS(MachineBlockHashInfo, "machine-block-hash",
+ "Machine Block Hash Analysis", true, true)
+
+char MachineBlockHashInfo::ID = 0;
+
+MachineBlockHashInfo::MachineBlockHashInfo() : MachineFunctionPass(ID) {
+ initializeMachineBlockHashInfoPass(*PassRegistry::getPassRegistry());
+}
+
+void MachineBlockHashInfo::getAnalysisUsage(AnalysisUsage &AU) const {
+ AU.setPreservesAll();
+ MachineFunctionPass::getAnalysisUsage(AU);
+}
+
+struct CollectHashInfo {
+ uint64_t Offset;
+ uint64_t OpcodeHash;
+ uint64_t InstrHash;
+ uint64_t NeighborHash;
+};
+
+bool MachineBlockHashInfo::runOnMachineFunction(MachineFunction &F) {
+ DenseMap<const MachineBasicBlock *, CollectHashInfo> HashInfos;
+ uint16_t Offset = 0;
+ // Initialize hash components
+ for (const MachineBasicBlock &MBB : F) {
+ // offset of the machine basic block
+ HashInfos[&MBB].Offset = Offset;
+ Offset += MBB.size();
+ // Hashing opcodes
+ HashInfos[&MBB].OpcodeHash = hashBlock(MBB, /*HashOperands=*/false);
+ // Hash complete instructions
+ HashInfos[&MBB].InstrHash = hashBlock(MBB, /*HashOperands=*/true);
+ }
+
+ // Initialize neighbor hash
+ for (const MachineBasicBlock &MBB : F) {
+ uint64_t Hash = HashInfos[&MBB].OpcodeHash;
+ // Append hashes of successors
+ for (const MachineBasicBlock *SuccMBB : MBB.successors()) {
+ uint64_t SuccHash = HashInfos[SuccMBB].OpcodeHash;
+ Hash = hashing::detail::hash_16_bytes(Hash, SuccHash);
+ }
+ // Append hashes of predecessors
+ for (const MachineBasicBlock *PredMBB : MBB.predecessors()) {
+ uint64_t PredHash = HashInfos[PredMBB].OpcodeHash;
+ Hash = hashing::detail::hash_16_bytes(Hash, PredHash);
+ }
+ HashInfos[&MBB].NeighborHash = Hash;
+ }
+
+ // Assign hashes
+ for (const MachineBasicBlock &MBB : F) {
+ const auto &HashInfo = HashInfos[&MBB];
+ BlendedBlockHash BlendedHash(fold_64_to_16(HashInfo.Offset),
+ fold_64_to_16(HashInfo.OpcodeHash),
+ fold_64_to_16(HashInfo.InstrHash),
+ fold_64_to_16(HashInfo.NeighborHash));
+ MBBHashInfo[&MBB] = BlendedHash.combine();
+ }
+
+ return false;
+}
+
+uint64_t MachineBlockHashInfo::getMBBHash(const MachineBasicBlock &MBB) {
+ return MBBHashInfo[&MBB];
+}
+
+MachineFunctionPass *llvm::createMachineBlockHashInfoPass() {
+ return new MachineBlockHashInfo();
+}
diff --git a/llvm/lib/CodeGen/TargetPassConfig.cpp b/llvm/lib/CodeGen/TargetPassConfig.cpp
index b6169e6..10b7238 100644
--- a/llvm/lib/CodeGen/TargetPassConfig.cpp
+++ b/llvm/lib/CodeGen/TargetPassConfig.cpp
@@ -272,6 +272,12 @@ static cl::opt<bool>
cl::desc("Split static data sections into hot and cold "
"sections using profile information"));
+cl::opt<bool> EmitBBHash(
+ "emit-bb-hash",
+ cl::desc(
+ "Emit the hash of basic block in the SHT_LLVM_BB_ADDR_MAP section."),
+ cl::init(false), cl::Optional);
+
/// Allow standard passes to be disabled by command line options. This supports
/// simple binary flags that either suppress the pass or do nothing.
/// i.e. -disable-mypass=false has no effect.
@@ -1281,6 +1287,8 @@ void TargetPassConfig::addMachinePasses() {
// address map (or both).
if (TM->getBBSectionsType() != llvm::BasicBlockSection::None ||
TM->Options.BBAddrMap) {
+ if (EmitBBHash)
+ addPass(llvm::createMachineBlockHashInfoPass());
if (TM->getBBSectionsType() == llvm::BasicBlockSection::List) {
addPass(llvm::createBasicBlockSectionsProfileReaderWrapperPass(
TM->getBBSectionsFuncListBuf()));
generated by cgit v1.1 at 2025-10-24 00:24:50 +0000