#include "llvm/IR/LegacyPassManager.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Verifier.h"
-#include "llvm/Linker/Linker.h"
+#include "llvm/Linker/IRMover.h"
#include "llvm/MC/SubtargetFeature.h"
-#include "llvm/Object/IRObjectFile.h"
#include "llvm/Object/FunctionIndexObjectFile.h"
-#include "llvm/Support/raw_ostream.h"
+#include "llvm/Object/IRObjectFile.h"
#include "llvm/Support/Host.h"
#include "llvm/Support/ManagedStatic.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/TargetRegistry.h"
#include "llvm/Support/TargetSelect.h"
+#include "llvm/Support/raw_ostream.h"
#include "llvm/Transforms/IPO.h"
#include "llvm/Transforms/IPO/PassManagerBuilder.h"
#include "llvm/Transforms/Utils/GlobalStatus.h"
using namespace llvm;
+static ld_plugin_status discard_message(int level, const char *format, ...) {
+ // Die loudly. Recent versions of Gold pass ld_plugin_message as the first
+ // callback in the transfer vector. This should never be called.
+ abort();
+}
+
+static ld_plugin_release_input_file release_input_file = nullptr;
+static ld_plugin_get_input_file get_input_file = nullptr;
+static ld_plugin_message message = discard_message;
+
namespace {
struct claimed_file {
void *handle;
std::vector<ld_plugin_symbol> syms;
};
-}
-static ld_plugin_status discard_message(int level, const char *format, ...) {
- // Die loudly. Recent versions of Gold pass ld_plugin_message as the first
- // callback in the transfer vector. This should never be called.
- abort();
+/// RAII wrapper to manage opening and releasing of a ld_plugin_input_file.
+struct PluginInputFile {
+ void *Handle;
+ ld_plugin_input_file File;
+
+ PluginInputFile(void *Handle) : Handle(Handle) {
+ if (get_input_file(Handle, &File) != LDPS_OK)
+ message(LDPL_FATAL, "Failed to get file information");
+ }
+ ~PluginInputFile() {
+ if (release_input_file(Handle) != LDPS_OK)
+ message(LDPL_FATAL, "Failed to release file information");
+ }
+ ld_plugin_input_file &file() { return File; }
+};
+
+struct ResolutionInfo {
+ bool IsLinkonceOdr = true;
+ bool UnnamedAddr = true;
+ GlobalValue::VisibilityTypes Visibility = GlobalValue::DefaultVisibility;
+ bool CommonInternal = false;
+ bool UseCommon = false;
+ unsigned CommonSize = 0;
+ unsigned CommonAlign = 0;
+ claimed_file *CommonFile = nullptr;
+};
}
-static ld_plugin_get_input_file get_input_file = nullptr;
-static ld_plugin_release_input_file release_input_file = nullptr;
static ld_plugin_add_symbols add_symbols = nullptr;
static ld_plugin_get_symbols get_symbols = nullptr;
static ld_plugin_add_input_file add_input_file = nullptr;
static ld_plugin_set_extra_library_path set_extra_library_path = nullptr;
static ld_plugin_get_view get_view = nullptr;
-static ld_plugin_message message = discard_message;
static Reloc::Model RelocationModel = Reloc::Default;
static std::string output_name = "";
static std::list<claimed_file> Modules;
+static StringMap<ResolutionInfo> ResInfo;
static std::vector<std::string> Cleanup;
static llvm::TargetOptions TargetOpts;
diagnosticHandler(DI);
}
+static GlobalValue::VisibilityTypes
+getMinVisibility(GlobalValue::VisibilityTypes A,
+ GlobalValue::VisibilityTypes B) {
+ if (A == GlobalValue::HiddenVisibility)
+ return A;
+ if (B == GlobalValue::HiddenVisibility)
+ return B;
+ if (A == GlobalValue::ProtectedVisibility)
+ return A;
+ return B;
+}
+
/// Called by gold to see whether this file is one that our plugin can handle.
/// We'll try to open it and register all the symbols with add_symbol if
/// possible.
const GlobalValue *GV = Obj->getSymbolGV(Sym.getRawDataRefImpl());
+ ResolutionInfo &Res = ResInfo[sym.name];
+
sym.visibility = LDPV_DEFAULT;
if (GV) {
+ Res.UnnamedAddr &= GV->hasUnnamedAddr();
+ Res.IsLinkonceOdr &= GV->hasLinkOnceLinkage();
+ if (GV->hasCommonLinkage()) {
+ Res.CommonAlign = std::max(Res.CommonAlign, GV->getAlignment());
+ const DataLayout &DL = GV->getParent()->getDataLayout();
+ uint64_t Size = DL.getTypeAllocSize(GV->getType()->getElementType());
+ if (Size >= Res.CommonSize) {
+ Res.CommonSize = Size;
+ Res.CommonFile = &cf;
+ }
+ }
+ Res.Visibility = getMinVisibility(Res.Visibility, GV->getVisibility());
switch (GV->getVisibility()) {
case GlobalValue::DefaultVisibility:
sym.visibility = LDPV_DEFAULT;
const Comdat *C = Base->getComdat();
if (C)
sym.comdat_key = strdup(C->getName().str().c_str());
- else if (Base->hasWeakLinkage() || Base->hasLinkOnceLinkage())
- sym.comdat_key = strdup(sym.name);
}
sym.resolution = LDPR_UNKNOWN;
return LDPS_OK;
}
-static void keepGlobalValue(GlobalValue &GV,
- std::vector<GlobalAlias *> &KeptAliases) {
- assert(!GV.hasLocalLinkage());
-
- if (auto *GA = dyn_cast<GlobalAlias>(&GV))
- KeptAliases.push_back(GA);
-
- switch (GV.getLinkage()) {
- default:
- break;
- case GlobalValue::LinkOnceAnyLinkage:
- GV.setLinkage(GlobalValue::WeakAnyLinkage);
- break;
- case GlobalValue::LinkOnceODRLinkage:
- GV.setLinkage(GlobalValue::WeakODRLinkage);
- break;
- }
-
- assert(!GV.isDiscardableIfUnused());
-}
-
static void internalize(GlobalValue &GV) {
if (GV.isDeclarationForLinker())
return; // We get here if there is a matching asm definition.
GV.setLinkage(GlobalValue::InternalLinkage);
}
-static void drop(GlobalValue &GV) {
- if (auto *F = dyn_cast<Function>(&GV)) {
- F->deleteBody();
- F->setComdat(nullptr); // Should deleteBody do this?
- return;
- }
-
- if (auto *Var = dyn_cast<GlobalVariable>(&GV)) {
- Var->setInitializer(nullptr);
- Var->setLinkage(
- GlobalValue::ExternalLinkage); // Should setInitializer do this?
- Var->setComdat(nullptr); // and this?
- return;
- }
-
- auto &Alias = cast<GlobalAlias>(GV);
- Module &M = *Alias.getParent();
- PointerType &Ty = *cast<PointerType>(Alias.getType());
- GlobalValue::LinkageTypes L = Alias.getLinkage();
- auto *Var =
- new GlobalVariable(M, Ty.getElementType(), /*isConstant*/ false, L,
- /*Initializer*/ nullptr);
- Var->takeName(&Alias);
- Alias.replaceAllUsesWith(Var);
- Alias.eraseFromParent();
-}
-
static const char *getResolutionName(ld_plugin_symbol_resolution R) {
switch (R) {
case LDPR_UNKNOWN:
llvm_unreachable("Unknown resolution");
}
-namespace {
-class LocalValueMaterializer final : public ValueMaterializer {
- DenseSet<GlobalValue *> &Dropped;
- DenseMap<GlobalObject *, GlobalObject *> LocalVersions;
-
-public:
- LocalValueMaterializer(DenseSet<GlobalValue *> &Dropped) : Dropped(Dropped) {}
- Value *materializeValueFor(Value *V) override;
-};
-}
-
-Value *LocalValueMaterializer::materializeValueFor(Value *V) {
- auto *GO = dyn_cast<GlobalObject>(V);
- if (!GO)
- return nullptr;
-
- auto I = LocalVersions.find(GO);
- if (I != LocalVersions.end())
- return I->second;
-
- if (!Dropped.count(GO))
- return nullptr;
-
- Module &M = *GO->getParent();
- GlobalValue::LinkageTypes L = GO->getLinkage();
- GlobalObject *Declaration;
- if (auto *F = dyn_cast<Function>(GO)) {
- Declaration = Function::Create(F->getFunctionType(), L, "", &M);
- } else {
- auto *Var = cast<GlobalVariable>(GO);
- Declaration = new GlobalVariable(M, Var->getType()->getElementType(),
- Var->isConstant(), L,
- /*Initializer*/ nullptr);
- }
- Declaration->takeName(GO);
- Declaration->copyAttributesFrom(GO);
-
- GO->setLinkage(GlobalValue::InternalLinkage);
- GO->setName(Declaration->getName());
- Dropped.erase(GO);
- GO->replaceAllUsesWith(Declaration);
-
- LocalVersions[Declaration] = GO;
-
- return GO;
-}
-
-static Constant *mapConstantToLocalCopy(Constant *C, ValueToValueMapTy &VM,
- LocalValueMaterializer *Materializer) {
- return MapValue(C, VM, RF_IgnoreMissingEntries, nullptr, Materializer);
-}
-
static void freeSymName(ld_plugin_symbol &Sym) {
free(Sym.name);
free(Sym.comdat_key);
MemoryBufferRef BufferRef(StringRef((const char *)View, Info.filesize),
Info.name);
+
+ // Don't bother trying to build an index if there is no summary information
+ // in this bitcode file.
+ if (!object::FunctionIndexObjectFile::hasFunctionSummaryInMemBuffer(
+ BufferRef, diagnosticHandler))
+ return std::unique_ptr<FunctionInfoIndex>(nullptr);
+
ErrorOr<std::unique_ptr<object::FunctionIndexObjectFile>> ObjOrErr =
object::FunctionIndexObjectFile::create(BufferRef, diagnosticHandler);
static std::unique_ptr<Module>
getModuleForFile(LLVMContext &Context, claimed_file &F,
ld_plugin_input_file &Info, raw_fd_ostream *ApiFile,
- StringSet<> &Internalize, StringSet<> &Maybe) {
+ StringSet<> &Internalize, StringSet<> &Maybe,
+ std::vector<GlobalValue *> &Keep) {
if (get_symbols(F.handle, F.syms.size(), F.syms.data()) != LDPS_OK)
message(LDPL_FATAL, "Failed to get symbol information");
SmallPtrSet<GlobalValue *, 8> Used;
collectUsedGlobalVariables(M, Used, /*CompilerUsed*/ false);
- DenseSet<GlobalValue *> Drop;
- std::vector<GlobalAlias *> KeptAliases;
-
unsigned SymNum = 0;
for (auto &ObjSym : Obj.symbols()) {
+ GlobalValue *GV = Obj.getSymbolGV(ObjSym.getRawDataRefImpl());
+ if (GV && GV->hasAppendingLinkage())
+ Keep.push_back(GV);
+
if (shouldSkip(ObjSym.getFlags()))
continue;
ld_plugin_symbol &Sym = F.syms[SymNum];
if (options::generate_api_file)
*ApiFile << Sym.name << ' ' << getResolutionName(Resolution) << '\n';
- GlobalValue *GV = Obj.getSymbolGV(ObjSym.getRawDataRefImpl());
if (!GV) {
freeSymName(Sym);
continue; // Asm symbol.
}
- if (Resolution != LDPR_PREVAILING_DEF_IRONLY && GV->hasCommonLinkage()) {
- // Common linkage is special. There is no single symbol that wins the
- // resolution. Instead we have to collect the maximum alignment and size.
- // The IR linker does that for us if we just pass it every common GV.
- // We still have to keep track of LDPR_PREVAILING_DEF_IRONLY so we
- // internalize once the IR linker has done its job.
- freeSymName(Sym);
- continue;
+ ResolutionInfo &Res = ResInfo[Sym.name];
+ if (Resolution == LDPR_PREVAILING_DEF_IRONLY_EXP && !Res.IsLinkonceOdr)
+ Resolution = LDPR_PREVAILING_DEF;
+
+ GV->setUnnamedAddr(Res.UnnamedAddr);
+ GV->setVisibility(Res.Visibility);
+
+ // Override gold's resolution for common symbols. We want the largest
+ // one to win.
+ if (GV->hasCommonLinkage()) {
+ cast<GlobalVariable>(GV)->setAlignment(Res.CommonAlign);
+ if (Resolution == LDPR_PREVAILING_DEF_IRONLY)
+ Res.CommonInternal = true;
+
+ if (Resolution == LDPR_PREVAILING_DEF_IRONLY ||
+ Resolution == LDPR_PREVAILING_DEF)
+ Res.UseCommon = true;
+
+ if (Res.CommonFile == &F && Res.UseCommon) {
+ if (Res.CommonInternal)
+ Resolution = LDPR_PREVAILING_DEF_IRONLY;
+ else
+ Resolution = LDPR_PREVAILING_DEF;
+ } else {
+ Resolution = LDPR_PREEMPTED_IR;
+ }
}
switch (Resolution) {
case LDPR_RESOLVED_IR:
case LDPR_RESOLVED_EXEC:
case LDPR_RESOLVED_DYN:
- assert(GV->isDeclarationForLinker());
+ case LDPR_PREEMPTED_IR:
+ case LDPR_PREEMPTED_REG:
break;
case LDPR_UNDEF:
- if (!GV->isDeclarationForLinker()) {
+ if (!GV->isDeclarationForLinker())
assert(GV->hasComdat());
- Drop.insert(GV);
- }
break;
case LDPR_PREVAILING_DEF_IRONLY: {
- keepGlobalValue(*GV, KeptAliases);
- if (!Used.count(GV)) {
- // Since we use the regular lib/Linker, we cannot just internalize GV
- // now or it will not be copied to the merged module. Instead we force
- // it to be copied and then internalize it.
+ Keep.push_back(GV);
+ // The IR linker has to be able to map this value to a declaration,
+ // so we can only internalize after linking.
+ if (!Used.count(GV))
Internalize.insert(GV->getName());
- }
break;
}
case LDPR_PREVAILING_DEF:
- keepGlobalValue(*GV, KeptAliases);
- break;
-
- case LDPR_PREEMPTED_IR:
- // Gold might have selected a linkonce_odr and preempted a weak_odr.
- // In that case we have to make sure we don't end up internalizing it.
- if (!GV->isDiscardableIfUnused())
- Maybe.erase(GV->getName());
-
- // fall-through
- case LDPR_PREEMPTED_REG:
- Drop.insert(GV);
+ Keep.push_back(GV);
+ // There is a non IR use, so we have to force optimizations to keep this.
+ switch (GV->getLinkage()) {
+ default:
+ break;
+ case GlobalValue::LinkOnceAnyLinkage:
+ GV->setLinkage(GlobalValue::WeakAnyLinkage);
+ break;
+ case GlobalValue::LinkOnceODRLinkage:
+ GV->setLinkage(GlobalValue::WeakODRLinkage);
+ break;
+ }
break;
case LDPR_PREVAILING_DEF_IRONLY_EXP: {
// reason is that this GV might have a copy in another module
// and in that module the address might be significant, but that
// copy will be LDPR_PREEMPTED_IR.
- if (GV->hasLinkOnceODRLinkage())
- Maybe.insert(GV->getName());
- keepGlobalValue(*GV, KeptAliases);
+ Maybe.insert(GV->getName());
+ Keep.push_back(GV);
break;
}
}
freeSymName(Sym);
}
- ValueToValueMapTy VM;
- LocalValueMaterializer Materializer(Drop);
- for (GlobalAlias *GA : KeptAliases) {
- // Gold told us to keep GA. It is possible that a GV usied in the aliasee
- // expression is being dropped. If that is the case, that GV must be copied.
- Constant *Aliasee = GA->getAliasee();
- Constant *Replacement = mapConstantToLocalCopy(Aliasee, VM, &Materializer);
- GA->setAliasee(Replacement);
- }
-
- for (auto *GV : Drop)
- drop(*GV);
-
return Obj.takeModule();
}
raw_fd_ostream OS(Path, EC, sys::fs::OpenFlags::F_None);
if (EC)
message(LDPL_FATAL, "Failed to write the output file.");
- WriteBitcodeToFile(&M, OS, /* ShouldPreserveUseListOrder */ true);
+ WriteBitcodeToFile(&M, OS, /* ShouldPreserveUseListOrder */ false);
}
static void codegen(std::unique_ptr<Module> M) {
if (Modules.empty())
return LDPS_OK;
- LLVMContext Context;
- Context.setDiagnosticHandler(diagnosticHandlerForContext, nullptr, true);
-
// If we are doing ThinLTO compilation, simply build the combined
// function index/summary and emit it. We don't need to parse the modules
// and link them in this case.
FunctionInfoIndex CombinedIndex;
uint64_t NextModuleId = 0;
for (claimed_file &F : Modules) {
- ld_plugin_input_file File;
- if (get_input_file(F.handle, &File) != LDPS_OK)
- message(LDPL_FATAL, "Failed to get file information");
+ PluginInputFile InputFile(F.handle);
std::unique_ptr<FunctionInfoIndex> Index =
- getFunctionIndexForFile(F, File);
- CombinedIndex.mergeFrom(std::move(Index), ++NextModuleId);
+ getFunctionIndexForFile(F, InputFile.file());
+
+ // Skip files without a function summary.
+ if (Index)
+ CombinedIndex.mergeFrom(std::move(Index), ++NextModuleId);
}
std::error_code EC;
exit(0);
}
+ LLVMContext Context;
+ Context.setDiagnosticHandler(diagnosticHandlerForContext, nullptr, true);
+
std::unique_ptr<Module> Combined(new Module("ld-temp.o", Context));
- Linker L(Combined.get());
+ IRMover L(*Combined);
std::string DefaultTriple = sys::getDefaultTargetTriple();
StringSet<> Internalize;
StringSet<> Maybe;
for (claimed_file &F : Modules) {
- ld_plugin_input_file File;
- if (get_input_file(F.handle, &File) != LDPS_OK)
- message(LDPL_FATAL, "Failed to get file information");
- std::unique_ptr<Module> M =
- getModuleForFile(Context, F, File, ApiFile, Internalize, Maybe);
+ PluginInputFile InputFile(F.handle);
+ std::vector<GlobalValue *> Keep;
+ std::unique_ptr<Module> M = getModuleForFile(
+ Context, F, InputFile.file(), ApiFile, Internalize, Maybe, Keep);
if (!options::triple.empty())
M->setTargetTriple(options::triple.c_str());
- else if (M->getTargetTriple().empty()) {
+ else if (M->getTargetTriple().empty())
M->setTargetTriple(DefaultTriple);
- }
- if (L.linkInModule(M.get()))
+ if (L.move(*M, Keep, [](GlobalValue &, IRMover::ValueAdder) {}))
message(LDPL_FATAL, "Failed to link module");
- if (release_input_file(F.handle) != LDPS_OK)
- message(LDPL_FATAL, "Failed to release file information");
}
for (const auto &Name : Internalize) {
path = output_name;
else
path = output_name + ".bc";
- saveBCFile(path, *L.getModule());
+ saveBCFile(path, *Combined);
if (options::TheOutputType == options::OT_BC_ONLY)
return LDPS_OK;
}
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