bolt/lib/Passes/AsmDump.cpp - llvm-project - Git at Google

 //===- bolt/Passes/AsmDump.cpp - Dump BinaryFunction into assembly --------===//
 //
 // 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
 //
 //===----------------------------------------------------------------------===//
 //
 // This file implements the AsmDumpPass class.
 //
 //===----------------------------------------------------------------------===//

 #include "bolt/Passes/AsmDump.h"
 #include "llvm/CodeGen/AsmPrinter.h"
 #include "llvm/MC/TargetRegistry.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Target/TargetMachine.h"
 #include <unordered_set>

 #define DEBUG_TYPE "asm-dump"

 using namespace llvm;

 namespace opts {
 extern bool shouldPrint(const bolt::BinaryFunction &Function);
 extern cl::OptionCategory BoltCategory;
 extern cl::opt<unsigned> Verbosity;

 cl::opt<std::string> AsmDump("asm-dump",
                              cl::desc("dump function into assembly"),
                              cl::value_desc("dump folder"), cl::ValueOptional,
                              cl::Hidden, cl::cat(BoltCategory));
 } // end namespace opts

 namespace llvm {
 namespace bolt {

 void dumpCFI(const BinaryFunction &BF, const MCInst &Instr, AsmPrinter &MAP) {
   const MCCFIInstruction *CFIInstr = BF.getCFIFor(Instr);
   switch (CFIInstr->getOperation()) {
   // Skip unsupported CFI instructions.
   case MCCFIInstruction::OpRememberState:
   case MCCFIInstruction::OpRestoreState:
     if (opts::Verbosity >= 2)
       errs()
           << "BOLT-WARNING: AsmDump: skipping unsupported CFI instruction in "
           << BF << ".\n";

     return;

   default:
     // Emit regular CFI instructions.
     MAP.emitCFIInstruction(*CFIInstr);
   }
 }

 void dumpJumpTableFdata(raw_ostream &OS, const BinaryFunction &BF,
                         const MCInst &Instr, const std::string &BranchLabel) {
   StringRef FunctionName = BF.getOneName();
   const JumpTable *JT = BF.getJumpTable(Instr);
   for (uint32_t i = 0; i < JT->Entries.size(); ++i) {
     StringRef TargetName = JT->Entries[i]->getName();
     const uint64_t Mispreds = JT->Counts[i].Mispreds;
     const uint64_t Count = JT->Counts[i].Count;
     OS << "# FDATA: 1 " << FunctionName << " #" << BranchLabel << "# "
        << "1 " << FunctionName << " #" << TargetName << "# " << Mispreds << " "
        << Count << '\n';
   }
 }

 void dumpTailCallFdata(raw_ostream &OS, const BinaryFunction &BF,
                        const MCInst &Instr, const std::string &BranchLabel) {
   const BinaryContext &BC = BF.getBinaryContext();
   StringRef FunctionName = BF.getOneName();
   auto CallFreq = BC.MIB->getAnnotationWithDefault<uint64_t>(Instr, "Count");
   const MCSymbol *Target = BC.MIB->getTargetSymbol(Instr);
   const BinaryFunction *TargetBF = BC.getFunctionForSymbol(Target);
   if (!TargetBF)
     return;
   OS << "# FDATA: 1 " << FunctionName << " #" << BranchLabel << "# "
      << "1 " << TargetBF->getPrintName() << " 0 "
      << "0 " << CallFreq << '\n';
 }

 void dumpTargetFunctionStub(raw_ostream &OS, const BinaryContext &BC,
                             const MCSymbol *CalleeSymb,
                             const BinarySection *&LastCS) {
   const BinaryFunction *CalleeFunc = BC.getFunctionForSymbol(CalleeSymb);
   if (!CalleeFunc || CalleeFunc->isPLTFunction())
     return;

   if (CalleeFunc->getOriginSection() != LastCS) {
     OS << ".section " << CalleeFunc->getOriginSectionName() << '\n';
     LastCS = CalleeFunc->getOriginSection();
   }
   StringRef CalleeName = CalleeFunc->getOneName();
   OS << ".set \"" << CalleeName << "\", 0\n";
 }

 void dumpJumpTableSymbols(raw_ostream &OS, const JumpTable *JT, AsmPrinter &MAP,
                           const BinarySection *&LastBS) {
   if (&JT->getSection() != LastBS) {
     OS << ".section " << JT->getSectionName() << '\n';
     LastBS = &JT->getSection();
   }
   OS << "\"" << JT->getName() << "\":\n";
   for (MCSymbol *JTEntry : JT->Entries)
     MAP.OutStreamer->emitSymbolValue(JTEntry, JT->OutputEntrySize);
   OS << '\n';
 }

 void dumpBinaryDataSymbols(raw_ostream &OS, const BinaryData *BD,
                            const BinarySection *&LastBS) {
   if (BD->isJumpTable())
     return;
   if (&BD->getSection() != LastBS) {
     OS << ".section " << BD->getSectionName() << '\n';
     LastBS = &BD->getSection();
   }
   OS << "\"" << BD->getName() << "\": ";
   OS << '\n';
 }

 void dumpFunction(const BinaryFunction &BF) {
   const BinaryContext &BC = BF.getBinaryContext();
   if (!opts::shouldPrint(BF))
     return;

   // Make sure the new directory exists, creating it if necessary.
   if (!opts::AsmDump.empty()) {
     if (std::error_code EC = sys::fs::create_directories(opts::AsmDump)) {
       errs() << "BOLT-ERROR: could not create directory '" << opts::AsmDump
              << "': " << EC.message() << '\n';
       exit(1);
     }
   }

   std::string PrintName = BF.getPrintName();
   std::replace(PrintName.begin(), PrintName.end(), '/', '-');
   std::string Filename =
       opts::AsmDump.empty()
           ? (PrintName + ".s")
           : (opts::AsmDump + sys::path::get_separator() + PrintName + ".s")
                 .str();
   outs() << "BOLT-INFO: Dumping function assembly to " << Filename << "\n";

   std::error_code EC;
   raw_fd_ostream OS(Filename, EC, sys::fs::OF_None);
   if (EC) {
     errs() << "BOLT-ERROR: " << EC.message() << ", unable to open " << Filename
            << " for output.\n";
     exit(1);
   }
   OS.SetUnbuffered();

   // Create local MC context to isolate the effect of ephemeral assembly
   // emission.
   BinaryContext::IndependentCodeEmitter MCEInstance =
       BC.createIndependentMCCodeEmitter();
   MCContext *LocalCtx = MCEInstance.LocalCtx.get();
   std::unique_ptr<MCAsmBackend> MAB(
       BC.TheTarget->createMCAsmBackend(*BC.STI, *BC.MRI, MCTargetOptions()));
   int AsmPrinterVariant = BC.AsmInfo->getAssemblerDialect();
   MCInstPrinter *InstructionPrinter(BC.TheTarget->createMCInstPrinter(
       *BC.TheTriple, AsmPrinterVariant, *BC.AsmInfo, *BC.MII, *BC.MRI));
   auto FOut = std::make_unique<formatted_raw_ostream>(OS);
   FOut->SetUnbuffered();
   std::unique_ptr<MCStreamer> AsmStreamer(
       createAsmStreamer(*LocalCtx, std::move(FOut),
                         /*isVerboseAsm=*/true,
                         /*useDwarfDirectory=*/false, InstructionPrinter,
                         std::move(MCEInstance.MCE), std::move(MAB),
                         /*ShowInst=*/false));
   AsmStreamer->initSections(true, *BC.STI);
   std::unique_ptr<TargetMachine> TM(BC.TheTarget->createTargetMachine(
       BC.TripleName, "", "", TargetOptions(), std::nullopt));
   std::unique_ptr<AsmPrinter> MAP(
       BC.TheTarget->createAsmPrinter(*TM, std::move(AsmStreamer)));

   StringRef FunctionName = BF.getOneName();
   OS << "  .globl " << FunctionName << '\n';
   OS << "  .type " << FunctionName << ", %function\n";
   OS << FunctionName << ":\n";

   // FDATA for the entry point
   if (uint64_t EntryExecCount = BF.getKnownExecutionCount())
     OS << "# FDATA: 0 [unknown] 0 "
        << "1 " << FunctionName << " 0 "
        << "0 " << EntryExecCount << '\n';

   // Binary data references from the function.
   std::unordered_set<const BinaryData *> BDReferences;
   // Function references from the function (to avoid constructing call graph).
   std::unordered_set<const MCSymbol *> CallReferences;

   MAP->OutStreamer->emitCFIStartProc(/*IsSimple=*/false);
   for (const BinaryBasicBlock *BB : BF.getLayout().blocks()) {
     OS << BB->getName() << ": \n";

     const std::string BranchLabel = Twine(BB->getName(), "_br").str();
     const MCInst *LastInst = BB->getLastNonPseudoInstr();

     for (const MCInst &Instr : *BB) {
       // Dump pseudo instructions (CFI)
       if (BC.MIB->isPseudo(Instr)) {
         if (BC.MIB->isCFI(Instr))
           dumpCFI(BF, Instr, *MAP.get());
         continue;
       }

       // Analyze symbol references (data, functions) from the instruction.
       bool IsCall = BC.MIB->isCall(Instr);
       for (const MCOperand &Operand : MCPlus::primeOperands(Instr)) {
         if (Operand.isExpr() &&
             Operand.getExpr()->getKind() == MCExpr::SymbolRef) {
           std::pair<const MCSymbol *, uint64_t> TSI =
               BC.MIB->getTargetSymbolInfo(Operand.getExpr());
           const MCSymbol *Symbol = TSI.first;
           if (IsCall)
             CallReferences.insert(Symbol);
           else if (const BinaryData *BD =
                        BC.getBinaryDataByName(Symbol->getName()))
             BDReferences.insert(BD);
         }
       }

       if (&Instr == LastInst && (BB->succ_size() || IsCall))
         OS << BranchLabel << ":\n";

       BC.InstPrinter->printInst(&Instr, 0, "", *BC.STI, OS);
       OS << '\n';

       // Dump profile data in FDATA format (as parsed by link_fdata).
       if (BC.MIB->getJumpTable(Instr))
         dumpJumpTableFdata(OS, BF, Instr, BranchLabel);
       else if (BC.MIB->isTailCall(Instr))
         dumpTailCallFdata(OS, BF, Instr, BranchLabel);
     }

     // Dump profile data in FDATA format (as parsed by link_fdata).
     for (const BinaryBasicBlock *Succ : BB->successors()) {
       const BinaryBasicBlock::BinaryBranchInfo BI = BB->getBranchInfo(*Succ);
       if (!BI.MispredictedCount && !BI.Count)
         continue;

       OS << "# FDATA: 1 " << FunctionName << " #" << BranchLabel << "# "
          << "1 " << FunctionName << " #" << Succ->getName() << "# "
          << BI.MispredictedCount << " " << BI.Count << '\n';
     }

     OS << '\n';
   }
   MAP->OutStreamer->emitCFIEndProc();

   OS << ".size " << FunctionName << ", .-" << FunctionName << '\n';

   const BinarySection *LastSection = BF.getOriginSection();
   // Print stubs for all target functions.
   for (const MCSymbol *CalleeSymb : CallReferences)
     dumpTargetFunctionStub(OS, BC, CalleeSymb, LastSection);

   OS << "# Jump tables\n";
   // Print all jump tables.
   for (auto &JTI : BF.jumpTables())
     dumpJumpTableSymbols(OS, JTI.second, *MAP.get(), LastSection);

   OS << "# BinaryData\n";
   // Print data references.
   for (const BinaryData *BD : BDReferences)
     dumpBinaryDataSymbols(OS, BD, LastSection);
 }

 void AsmDumpPass::runOnFunctions(BinaryContext &BC) {
   for (const auto &BFIt : BC.getBinaryFunctions())
     dumpFunction(BFIt.second);
 }

 } // namespace bolt
 } // namespace llvm
	//===- bolt/Passes/AsmDump.cpp - Dump BinaryFunction into assembly --------===//
	//
	// 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
	//
	//===----------------------------------------------------------------------===//
	//
	// This file implements the AsmDumpPass class.
	//
	//===----------------------------------------------------------------------===//

	#include "bolt/Passes/AsmDump.h"
	#include "llvm/CodeGen/AsmPrinter.h"
	#include "llvm/MC/TargetRegistry.h"
	#include "llvm/Support/FileSystem.h"
	#include "llvm/Support/Path.h"
	#include "llvm/Target/TargetMachine.h"
	#include <unordered_set>

	#define DEBUG_TYPE "asm-dump"

	using namespace llvm;

	namespace opts {
	extern bool shouldPrint(const bolt::BinaryFunction &Function);
	extern cl::OptionCategory BoltCategory;
	extern cl::opt<unsigned> Verbosity;

	cl::opt<std::string> AsmDump("asm-dump",
	cl::desc("dump function into assembly"),
	cl::value_desc("dump folder"), cl::ValueOptional,
	cl::Hidden, cl::cat(BoltCategory));
	} // end namespace opts

	namespace llvm {
	namespace bolt {

	void dumpCFI(const BinaryFunction &BF, const MCInst &Instr, AsmPrinter &MAP) {
	const MCCFIInstruction *CFIInstr = BF.getCFIFor(Instr);
	switch (CFIInstr->getOperation()) {
	// Skip unsupported CFI instructions.
	case MCCFIInstruction::OpRememberState:
	case MCCFIInstruction::OpRestoreState:
	if (opts::Verbosity >= 2)
	errs()
	<< "BOLT-WARNING: AsmDump: skipping unsupported CFI instruction in "
	<< BF << ".\n";

	return;

	default:
	// Emit regular CFI instructions.
	MAP.emitCFIInstruction(*CFIInstr);
	}
	}

	void dumpJumpTableFdata(raw_ostream &OS, const BinaryFunction &BF,
	const MCInst &Instr, const std::string &BranchLabel) {
	StringRef FunctionName = BF.getOneName();
	const JumpTable *JT = BF.getJumpTable(Instr);
	for (uint32_t i = 0; i < JT->Entries.size(); ++i) {
	StringRef TargetName = JT->Entries[i]->getName();
	const uint64_t Mispreds = JT->Counts[i].Mispreds;
	const uint64_t Count = JT->Counts[i].Count;
	OS << "# FDATA: 1 " << FunctionName << " #" << BranchLabel << "# "
	<< "1 " << FunctionName << " #" << TargetName << "# " << Mispreds << " "
	<< Count << '\n';
	}
	}

	void dumpTailCallFdata(raw_ostream &OS, const BinaryFunction &BF,
	const MCInst &Instr, const std::string &BranchLabel) {
	const BinaryContext &BC = BF.getBinaryContext();
	StringRef FunctionName = BF.getOneName();
	auto CallFreq = BC.MIB->getAnnotationWithDefault<uint64_t>(Instr, "Count");
	const MCSymbol *Target = BC.MIB->getTargetSymbol(Instr);
	const BinaryFunction *TargetBF = BC.getFunctionForSymbol(Target);
	if (!TargetBF)
	return;
	OS << "# FDATA: 1 " << FunctionName << " #" << BranchLabel << "# "
	<< "1 " << TargetBF->getPrintName() << " 0 "
	<< "0 " << CallFreq << '\n';
	}

	void dumpTargetFunctionStub(raw_ostream &OS, const BinaryContext &BC,
	const MCSymbol *CalleeSymb,
	const BinarySection *&LastCS) {
	const BinaryFunction *CalleeFunc = BC.getFunctionForSymbol(CalleeSymb);
	if (!CalleeFunc \|\| CalleeFunc->isPLTFunction())
	return;

	if (CalleeFunc->getOriginSection() != LastCS) {
	OS << ".section " << CalleeFunc->getOriginSectionName() << '\n';
	LastCS = CalleeFunc->getOriginSection();
	}
	StringRef CalleeName = CalleeFunc->getOneName();
	OS << ".set \"" << CalleeName << "\", 0\n";
	}

	void dumpJumpTableSymbols(raw_ostream &OS, const JumpTable *JT, AsmPrinter &MAP,
	const BinarySection *&LastBS) {
	if (&JT->getSection() != LastBS) {
	OS << ".section " << JT->getSectionName() << '\n';
	LastBS = &JT->getSection();
	}
	OS << "\"" << JT->getName() << "\":\n";
	for (MCSymbol *JTEntry : JT->Entries)
	MAP.OutStreamer->emitSymbolValue(JTEntry, JT->OutputEntrySize);
	OS << '\n';
	}

	void dumpBinaryDataSymbols(raw_ostream &OS, const BinaryData *BD,
	const BinarySection *&LastBS) {
	if (BD->isJumpTable())
	return;
	if (&BD->getSection() != LastBS) {
	OS << ".section " << BD->getSectionName() << '\n';
	LastBS = &BD->getSection();
	}
	OS << "\"" << BD->getName() << "\": ";
	OS << '\n';
	}

	void dumpFunction(const BinaryFunction &BF) {
	const BinaryContext &BC = BF.getBinaryContext();
	if (!opts::shouldPrint(BF))
	return;

	// Make sure the new directory exists, creating it if necessary.
	if (!opts::AsmDump.empty()) {
	if (std::error_code EC = sys::fs::create_directories(opts::AsmDump)) {
	errs() << "BOLT-ERROR: could not create directory '" << opts::AsmDump
	<< "': " << EC.message() << '\n';
	exit(1);
	}
	}

	std::string PrintName = BF.getPrintName();
	std::replace(PrintName.begin(), PrintName.end(), '/', '-');
	std::string Filename =
	opts::AsmDump.empty()
	? (PrintName + ".s")
	: (opts::AsmDump + sys::path::get_separator() + PrintName + ".s")
	.str();
	outs() << "BOLT-INFO: Dumping function assembly to " << Filename << "\n";

	std::error_code EC;
	raw_fd_ostream OS(Filename, EC, sys::fs::OF_None);
	if (EC) {
	errs() << "BOLT-ERROR: " << EC.message() << ", unable to open " << Filename
	<< " for output.\n";
	exit(1);
	}
	OS.SetUnbuffered();

	// Create local MC context to isolate the effect of ephemeral assembly
	// emission.
	BinaryContext::IndependentCodeEmitter MCEInstance =
	BC.createIndependentMCCodeEmitter();
	MCContext *LocalCtx = MCEInstance.LocalCtx.get();
	std::unique_ptr<MCAsmBackend> MAB(
	BC.TheTarget->createMCAsmBackend(BC.STI, BC.MRI, MCTargetOptions()));
	int AsmPrinterVariant = BC.AsmInfo->getAssemblerDialect();
	MCInstPrinter *InstructionPrinter(BC.TheTarget->createMCInstPrinter(
	BC.TheTriple, AsmPrinterVariant, BC.AsmInfo, BC.MII, BC.MRI));
	auto FOut = std::make_unique<formatted_raw_ostream>(OS);
	FOut->SetUnbuffered();
	std::unique_ptr<MCStreamer> AsmStreamer(
	createAsmStreamer(*LocalCtx, std::move(FOut),
	/isVerboseAsm=/true,
	/useDwarfDirectory=/false, InstructionPrinter,
	std::move(MCEInstance.MCE), std::move(MAB),
	/ShowInst=/false));
	AsmStreamer->initSections(true, *BC.STI);
	std::unique_ptr<TargetMachine> TM(BC.TheTarget->createTargetMachine(
	BC.TripleName, "", "", TargetOptions(), std::nullopt));
	std::unique_ptr<AsmPrinter> MAP(
	BC.TheTarget->createAsmPrinter(*TM, std::move(AsmStreamer)));

	StringRef FunctionName = BF.getOneName();
	OS << " .globl " << FunctionName << '\n';
	OS << " .type " << FunctionName << ", %function\n";
	OS << FunctionName << ":\n";

	// FDATA for the entry point
	if (uint64_t EntryExecCount = BF.getKnownExecutionCount())
	OS << "# FDATA: 0 [unknown] 0 "
	<< "1 " << FunctionName << " 0 "
	<< "0 " << EntryExecCount << '\n';

	// Binary data references from the function.
	std::unordered_set<const BinaryData *> BDReferences;
	// Function references from the function (to avoid constructing call graph).
	std::unordered_set<const MCSymbol *> CallReferences;

	MAP->OutStreamer->emitCFIStartProc(/IsSimple=/false);
	for (const BinaryBasicBlock *BB : BF.getLayout().blocks()) {
	OS << BB->getName() << ": \n";

	const std::string BranchLabel = Twine(BB->getName(), "_br").str();
	const MCInst *LastInst = BB->getLastNonPseudoInstr();

	for (const MCInst &Instr : *BB) {
	// Dump pseudo instructions (CFI)
	if (BC.MIB->isPseudo(Instr)) {
	if (BC.MIB->isCFI(Instr))
	dumpCFI(BF, Instr, *MAP.get());
	continue;
	}

	// Analyze symbol references (data, functions) from the instruction.
	bool IsCall = BC.MIB->isCall(Instr);
	for (const MCOperand &Operand : MCPlus::primeOperands(Instr)) {
	if (Operand.isExpr() &&
	Operand.getExpr()->getKind() == MCExpr::SymbolRef) {
	std::pair<const MCSymbol *, uint64_t> TSI =
	BC.MIB->getTargetSymbolInfo(Operand.getExpr());
	const MCSymbol *Symbol = TSI.first;
	if (IsCall)
	CallReferences.insert(Symbol);
	else if (const BinaryData *BD =
	BC.getBinaryDataByName(Symbol->getName()))
	BDReferences.insert(BD);
	}
	}

	if (&Instr == LastInst && (BB->succ_size() \|\| IsCall))
	OS << BranchLabel << ":\n";

	BC.InstPrinter->printInst(&Instr, 0, "", *BC.STI, OS);
	OS << '\n';

	// Dump profile data in FDATA format (as parsed by link_fdata).
	if (BC.MIB->getJumpTable(Instr))
	dumpJumpTableFdata(OS, BF, Instr, BranchLabel);
	else if (BC.MIB->isTailCall(Instr))
	dumpTailCallFdata(OS, BF, Instr, BranchLabel);
	}

	// Dump profile data in FDATA format (as parsed by link_fdata).
	for (const BinaryBasicBlock *Succ : BB->successors()) {
	const BinaryBasicBlock::BinaryBranchInfo BI = BB->getBranchInfo(*Succ);
	if (!BI.MispredictedCount && !BI.Count)
	continue;

	OS << "# FDATA: 1 " << FunctionName << " #" << BranchLabel << "# "
	<< "1 " << FunctionName << " #" << Succ->getName() << "# "
	<< BI.MispredictedCount << " " << BI.Count << '\n';
	}

	OS << '\n';
	}
	MAP->OutStreamer->emitCFIEndProc();

	OS << ".size " << FunctionName << ", .-" << FunctionName << '\n';

	const BinarySection *LastSection = BF.getOriginSection();
	// Print stubs for all target functions.
	for (const MCSymbol *CalleeSymb : CallReferences)
	dumpTargetFunctionStub(OS, BC, CalleeSymb, LastSection);

	OS << "# Jump tables\n";
	// Print all jump tables.
	for (auto &JTI : BF.jumpTables())
	dumpJumpTableSymbols(OS, JTI.second, *MAP.get(), LastSection);

	OS << "# BinaryData\n";
	// Print data references.
	for (const BinaryData *BD : BDReferences)
	dumpBinaryDataSymbols(OS, BD, LastSection);
	}

	void AsmDumpPass::runOnFunctions(BinaryContext &BC) {
	for (const auto &BFIt : BC.getBinaryFunctions())
	dumpFunction(BFIt.second);
	}

	} // namespace bolt
	} // namespace llvm