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//===- ModuleSymbolTable.cpp - symbol table for in-memory IR --------------===//
//
// 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 class represents a symbol table built from in-memory IR. It provides
// access to GlobalValues and should only be used if such access is required
// (e.g. in the LTO implementation).
//
//===----------------------------------------------------------------------===//
#include "llvm/Object/ModuleSymbolTable.h"
#include "RecordStreamer.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/Triple.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/GlobalAlias.h"
#include "llvm/IR/GlobalValue.h"
#include "llvm/IR/GlobalVariable.h"
#include "llvm/IR/InlineAsm.h"
#include "llvm/IR/Module.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCInstrInfo.h"
#include "llvm/MC/MCObjectFileInfo.h"
#include "llvm/MC/MCParser/MCAsmParser.h"
#include "llvm/MC/MCParser/MCTargetAsmParser.h"
#include "llvm/MC/MCRegisterInfo.h"
#include "llvm/MC/MCSubtargetInfo.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/MC/MCTargetOptions.h"
#include "llvm/MC/TargetRegistry.h"
#include "llvm/Object/SymbolicFile.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/SMLoc.h"
#include "llvm/Support/SourceMgr.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm>
#include <cassert>
#include <cstdint>
#include <memory>
#include <string>
using namespace llvm;
using namespace object;
void ModuleSymbolTable::addModule(Module *M) {
if (FirstMod)
assert(FirstMod->getTargetTriple() == M->getTargetTriple());
else
FirstMod = M;
for (GlobalValue &GV : M->global_values())
SymTab.push_back(&GV);
CollectAsmSymbols(*M, [this](StringRef Name, BasicSymbolRef::Flags Flags) {
SymTab.push_back(new (AsmSymbols.Allocate())
AsmSymbol(std::string(Name), Flags));
});
}
static void
initializeRecordStreamer(const Module &M,
function_ref<void(RecordStreamer &)> Init) {
StringRef InlineAsm = M.getModuleInlineAsm();
if (InlineAsm.empty())
return;
std::string Err;
const Triple TT(M.getTargetTriple());
const Target *T = TargetRegistry::lookupTarget(TT.str(), Err);
assert(T && T->hasMCAsmParser());
std::unique_ptr<MCRegisterInfo> MRI(T->createMCRegInfo(TT.str()));
if (!MRI)
return;
MCTargetOptions MCOptions;
std::unique_ptr<MCAsmInfo> MAI(T->createMCAsmInfo(*MRI, TT.str(), MCOptions));
if (!MAI)
return;
std::unique_ptr<MCSubtargetInfo> STI(
T->createMCSubtargetInfo(TT.str(), "", ""));
if (!STI)
return;
std::unique_ptr<MCInstrInfo> MCII(T->createMCInstrInfo());
if (!MCII)
return;
std::unique_ptr<MemoryBuffer> Buffer(MemoryBuffer::getMemBuffer(InlineAsm));
SourceMgr SrcMgr;
SrcMgr.AddNewSourceBuffer(std::move(Buffer), SMLoc());
MCContext MCCtx(TT, MAI.get(), MRI.get(), STI.get(), &SrcMgr);
std::unique_ptr<MCObjectFileInfo> MOFI(
T->createMCObjectFileInfo(MCCtx, /*PIC=*/false));
MOFI->setSDKVersion(M.getSDKVersion());
MCCtx.setObjectFileInfo(MOFI.get());
RecordStreamer Streamer(MCCtx, M);
T->createNullTargetStreamer(Streamer);
std::unique_ptr<MCAsmParser> Parser(
createMCAsmParser(SrcMgr, MCCtx, Streamer, *MAI));
std::unique_ptr<MCTargetAsmParser> TAP(
T->createMCAsmParser(*STI, *Parser, *MCII, MCOptions));
if (!TAP)
return;
// Module-level inline asm is assumed to use At&t syntax (see
// AsmPrinter::doInitialization()).
Parser->setAssemblerDialect(InlineAsm::AD_ATT);
Parser->setTargetParser(*TAP);
if (Parser->Run(false))
return;
Init(Streamer);
}
void ModuleSymbolTable::CollectAsmSymbols(
const Module &M,
function_ref<void(StringRef, BasicSymbolRef::Flags)> AsmSymbol) {
initializeRecordStreamer(M, [&](RecordStreamer &Streamer) {
Streamer.flushSymverDirectives();
for (auto &KV : Streamer) {
StringRef Key = KV.first();
RecordStreamer::State Value = KV.second;
// FIXME: For now we just assume that all asm symbols are executable.
uint32_t Res = BasicSymbolRef::SF_Executable;
switch (Value) {
case RecordStreamer::NeverSeen:
llvm_unreachable("NeverSeen should have been replaced earlier");
case RecordStreamer::DefinedGlobal:
Res |= BasicSymbolRef::SF_Global;
break;
case RecordStreamer::Defined:
break;
case RecordStreamer::Global:
case RecordStreamer::Used:
Res |= BasicSymbolRef::SF_Undefined;
Res |= BasicSymbolRef::SF_Global;
break;
case RecordStreamer::DefinedWeak:
Res |= BasicSymbolRef::SF_Weak;
Res |= BasicSymbolRef::SF_Global;
break;
case RecordStreamer::UndefinedWeak:
Res |= BasicSymbolRef::SF_Weak;
Res |= BasicSymbolRef::SF_Undefined;
}
AsmSymbol(Key, BasicSymbolRef::Flags(Res));
}
});
}
void ModuleSymbolTable::CollectAsmSymvers(
const Module &M, function_ref<void(StringRef, StringRef)> AsmSymver) {
initializeRecordStreamer(M, [&](RecordStreamer &Streamer) {
for (auto &KV : Streamer.symverAliases())
for (auto &Alias : KV.second)
AsmSymver(KV.first->getName(), Alias);
});
}
void ModuleSymbolTable::printSymbolName(raw_ostream &OS, Symbol S) const {
if (S.is<AsmSymbol *>()) {
OS << S.get<AsmSymbol *>()->first;
return;
}
auto *GV = S.get<GlobalValue *>();
if (GV->hasDLLImportStorageClass())
OS << "__imp_";
Mang.getNameWithPrefix(OS, GV, false);
}
uint32_t ModuleSymbolTable::getSymbolFlags(Symbol S) const {
if (S.is<AsmSymbol *>())
return S.get<AsmSymbol *>()->second;
auto *GV = S.get<GlobalValue *>();
uint32_t Res = BasicSymbolRef::SF_None;
if (GV->isDeclarationForLinker())
Res |= BasicSymbolRef::SF_Undefined;
else if (GV->hasHiddenVisibility() && !GV->hasLocalLinkage())
Res |= BasicSymbolRef::SF_Hidden;
if (const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV)) {
if (GVar->isConstant())
Res |= BasicSymbolRef::SF_Const;
}
if (const GlobalObject *GO = GV->getAliaseeObject())
if (isa<Function>(GO) || isa<GlobalIFunc>(GO))
Res |= BasicSymbolRef::SF_Executable;
if (isa<GlobalAlias>(GV))
Res |= BasicSymbolRef::SF_Indirect;
if (GV->hasPrivateLinkage())
Res |= BasicSymbolRef::SF_FormatSpecific;
if (!GV->hasLocalLinkage())
Res |= BasicSymbolRef::SF_Global;
if (GV->hasCommonLinkage())
Res |= BasicSymbolRef::SF_Common;
if (GV->hasLinkOnceLinkage() || GV->hasWeakLinkage() ||
GV->hasExternalWeakLinkage())
Res |= BasicSymbolRef::SF_Weak;
if (GV->getName().startswith("llvm."))
Res |= BasicSymbolRef::SF_FormatSpecific;
else if (auto *Var = dyn_cast<GlobalVariable>(GV)) {
if (Var->getSection() == "llvm.metadata")
Res |= BasicSymbolRef::SF_FormatSpecific;
}
return Res;
}
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