https://github.com/mysterymath created https://github.com/llvm/llvm-project/pull/190642
This reverts commit 1ec7e86b3a779df2a0af3f37e58c8f5b3a398d7f after issue #190072 was fixed. >From 73f4aeb49f6125a081f73f459471797e70b1150e Mon Sep 17 00:00:00 2001 From: Daniel Thornburgh <[email protected]> Date: Mon, 6 Apr 2026 11:20:46 -0700 Subject: [PATCH] Reland "[LTO][LLD] Prevent invalid LTO libfunc transforms (#164916)" This reverts commit 1ec7e86b3a779df2a0af3f37e58c8f5b3a398d7f after issue #190072 was fixed. --- clang/lib/CodeGen/BackendUtil.cpp | 12 ++-- lld/COFF/InputFiles.cpp | 5 +- lld/COFF/LTO.cpp | 4 ++ lld/COFF/LTO.h | 1 + lld/COFF/SymbolTable.cpp | 24 +++++++ lld/ELF/Driver.cpp | 19 +++++ lld/ELF/LTO.cpp | 4 ++ lld/ELF/LTO.h | 1 + .../COFF/lto-libcall-archive-bitcode.test | 51 +++++++++++++ lld/test/ELF/lto/libcall-archive-bitcode.test | 54 ++++++++++++++ lld/test/wasm/lto/libcall-archive-bitcode.ll | 56 +++++++++++++++ lld/wasm/LTO.cpp | 4 ++ lld/wasm/LTO.h | 1 + lld/wasm/SymbolTable.cpp | 23 ++++++ llvm/docs/ReleaseNotes.md | 7 ++ llvm/include/llvm/LTO/LTO.h | 29 ++++++-- llvm/include/llvm/LTO/LTOBackend.h | 22 +++--- llvm/lib/LTO/LTO.cpp | 71 ++++++++++++++----- llvm/lib/LTO/LTOBackend.cpp | 34 +++++++-- llvm/lib/LTO/LTOCodeGenerator.cpp | 4 +- llvm/lib/LTO/ThinLTOCodeGenerator.cpp | 4 +- .../LTO/Resolution/X86/libcall-external.ll | 25 +++++++ .../Resolution/X86/libcall-in-thin-link.ll | 35 +++++++++ llvm/test/LTO/Resolution/X86/libcall-in-tu.ll | 34 +++++++++ llvm/tools/llvm-lto2/llvm-lto2.cpp | 16 +++++ 25 files changed, 488 insertions(+), 52 deletions(-) create mode 100644 lld/test/COFF/lto-libcall-archive-bitcode.test create mode 100644 lld/test/ELF/lto/libcall-archive-bitcode.test create mode 100644 lld/test/wasm/lto/libcall-archive-bitcode.ll create mode 100644 llvm/test/LTO/Resolution/X86/libcall-external.ll create mode 100644 llvm/test/LTO/Resolution/X86/libcall-in-thin-link.ll create mode 100644 llvm/test/LTO/Resolution/X86/libcall-in-tu.ll diff --git a/clang/lib/CodeGen/BackendUtil.cpp b/clang/lib/CodeGen/BackendUtil.cpp index 5b8b4083c2ac0..74c8bf1c670da 100644 --- a/clang/lib/CodeGen/BackendUtil.cpp +++ b/clang/lib/CodeGen/BackendUtil.cpp @@ -1410,12 +1410,14 @@ runThinLTOBackend(CompilerInstance &CI, ModuleSummaryIndex *CombinedIndex, // FIXME: Both ExecuteAction and thinBackend set up optimization remarks for // the same context. + // FIXME: This does not yet set the list of bitcode libfuncs that it isn't + // safe to call. This precludes bitcode libc in distributed ThinLTO. finalizeLLVMOptimizationRemarks(M->getContext()); - if (Error E = - thinBackend(Conf, -1, AddStream, *M, *CombinedIndex, ImportList, - ModuleToDefinedGVSummaries[M->getModuleIdentifier()], - /*ModuleMap=*/nullptr, Conf.CodeGenOnly, - /*IRAddStream=*/nullptr, CGOpts.CmdArgs)) { + if (Error E = thinBackend( + Conf, -1, AddStream, *M, *CombinedIndex, ImportList, + ModuleToDefinedGVSummaries[M->getModuleIdentifier()], + /*ModuleMap=*/nullptr, Conf.CodeGenOnly, /*BitcodeLibFuncs=*/{}, + /*IRAddStream=*/nullptr, CGOpts.CmdArgs)) { handleAllErrors(std::move(E), [&](ErrorInfoBase &EIB) { errs() << "Error running ThinLTO backend: " << EIB.message() << '\n'; }); diff --git a/lld/COFF/InputFiles.cpp b/lld/COFF/InputFiles.cpp index e797da6effb35..9040d9653d2b2 100644 --- a/lld/COFF/InputFiles.cpp +++ b/lld/COFF/InputFiles.cpp @@ -25,7 +25,6 @@ #include "llvm/DebugInfo/PDB/Native/NativeSession.h" #include "llvm/DebugInfo/PDB/Native/PDBFile.h" #include "llvm/IR/Mangler.h" -#include "llvm/IR/RuntimeLibcalls.h" #include "llvm/LTO/LTO.h" #include "llvm/Object/Binary.h" #include "llvm/Object/COFF.h" @@ -1394,8 +1393,6 @@ void BitcodeFile::parse() { // FIXME: Check nodeduplicate comdat[i] = symtab.addComdat(this, saver.save(obj->getComdatTable()[i].first)); - Triple tt(obj->getTargetTriple()); - RTLIB::RuntimeLibcallsInfo libcalls(tt); for (const lto::InputFile::Symbol &objSym : obj->symbols()) { StringRef symName = saver.save(objSym.getName()); int comdatIndex = objSym.getComdatIndex(); @@ -1445,7 +1442,7 @@ void BitcodeFile::parse() { symtab.addRegular(this, symName, nullptr, fakeSC, 0, objSym.isWeak()); } symbols.push_back(sym); - if (objSym.isUsed() || objSym.isLibcall(libcalls)) + if (objSym.isUsed()) symtab.ctx.config.gcroot.push_back(sym); } directives = saver.save(obj->getCOFFLinkerOpts()); diff --git a/lld/COFF/LTO.cpp b/lld/COFF/LTO.cpp index 2d38a13830dad..445ea52e995da 100644 --- a/lld/COFF/LTO.cpp +++ b/lld/COFF/LTO.cpp @@ -288,3 +288,7 @@ std::vector<InputFile *> BitcodeCompiler::compile() { return ret; } + +void BitcodeCompiler::setBitcodeLibFuncs(ArrayRef<StringRef> bitcodeLibFuncs) { + ltoObj->setBitcodeLibFuncs(bitcodeLibFuncs); +} diff --git a/lld/COFF/LTO.h b/lld/COFF/LTO.h index 6826251b5ffa7..73e855e567b09 100644 --- a/lld/COFF/LTO.h +++ b/lld/COFF/LTO.h @@ -45,6 +45,7 @@ class BitcodeCompiler { void add(BitcodeFile &f); std::vector<InputFile *> compile(); + void setBitcodeLibFuncs(ArrayRef<StringRef> bitcodeLibFuncs); private: std::unique_ptr<llvm::lto::LTO> ltoObj; diff --git a/lld/COFF/SymbolTable.cpp b/lld/COFF/SymbolTable.cpp index 38a43390c15ab..fef9bc54fd8a6 100644 --- a/lld/COFF/SymbolTable.cpp +++ b/lld/COFF/SymbolTable.cpp @@ -1437,13 +1437,37 @@ void SymbolTable::compileBitcodeFiles() { if (bitcodeFileInstances.empty()) return; + // Collect the bitcode library functions that are not safe to call because + // they were not yet brought in the link. (Such symbols are lazy.) + llvm::BumpPtrAllocator alloc; + llvm::StringSaver saver(alloc); + SmallVector<StringRef> bitcodeLibFuncs; + // Triple must be captured before the bitcode is moved into the compiler. + // Note that the below assumes that the set of possible libfuncs is roughly + // equivalent for all bitcode translation units. + llvm::Triple tt = + llvm::Triple(bitcodeFileInstances.front()->obj->getTargetTriple()); + for (StringRef libFunc : lto::LTO::getLibFuncSymbols(tt, saver)) { + if (Symbol *sym = find(libFunc)) { + if (auto *l = dyn_cast<LazyArchive>(sym)) { + if (isBitcode(l->getMemberBuffer())) + bitcodeLibFuncs.push_back(libFunc); + } else if (auto *o = dyn_cast<LazyObject>(sym)) { + if (isBitcode(o->file->mb)) + bitcodeLibFuncs.push_back(libFunc); + } + } + } + ScopedTimer t(ctx.ltoTimer); lto.reset(new BitcodeCompiler(ctx)); + lto->setBitcodeLibFuncs(bitcodeLibFuncs); { llvm::TimeTraceScope addScope("Add bitcode file instances"); for (BitcodeFile *f : bitcodeFileInstances) lto->add(*f); } + for (InputFile *newObj : lto->compile()) { ObjFile *obj = cast<ObjFile>(newObj); obj->parse(); diff --git a/lld/ELF/Driver.cpp b/lld/ELF/Driver.cpp index 949314fd70ed2..09aa6af5ee2c7 100644 --- a/lld/ELF/Driver.cpp +++ b/lld/ELF/Driver.cpp @@ -2774,8 +2774,27 @@ static void markBuffersAsDontNeed(Ctx &ctx, bool skipLinkedOutput) { template <class ELFT> void LinkerDriver::compileBitcodeFiles(bool skipLinkedOutput) { llvm::TimeTraceScope timeScope("LTO"); + + // Collect the bitcode library functions that are not safe to call because + // they were not yet brought in the link. (Such symbols are lazy.) + llvm::BumpPtrAllocator alloc; + llvm::StringSaver saver(alloc); + SmallVector<StringRef> bitcodeLibFuncs; + if (!ctx.bitcodeFiles.empty()) { + // Triple must be captured before the bitcode is moved into the compiler. + // Note that the below assumes that the set of possible libfuncs is roughly + // equivalent for all bitcode translation units. + llvm::Triple tt = + llvm::Triple(ctx.bitcodeFiles.front()->obj->getTargetTriple()); + for (StringRef libFunc : lto::LTO::getLibFuncSymbols(tt, saver)) + if (Symbol *sym = ctx.symtab->find(libFunc); + sym && sym->isLazy() && isa<BitcodeFile>(sym->file)) + bitcodeLibFuncs.push_back(libFunc); + } + // Compile bitcode files and replace bitcode symbols. lto.reset(new BitcodeCompiler(ctx)); + lto->setBitcodeLibFuncs(bitcodeLibFuncs); for (BitcodeFile *file : ctx.bitcodeFiles) lto->add(*file); diff --git a/lld/ELF/LTO.cpp b/lld/ELF/LTO.cpp index 352848af1551d..7b0fe2001439e 100644 --- a/lld/ELF/LTO.cpp +++ b/lld/ELF/LTO.cpp @@ -436,3 +436,7 @@ SmallVector<std::unique_ptr<InputFile>, 0> BitcodeCompiler::compile() { } return ret; } + +void BitcodeCompiler::setBitcodeLibFuncs(ArrayRef<StringRef> bitcodeLibFuncs) { + ltoObj->setBitcodeLibFuncs(bitcodeLibFuncs); +} diff --git a/lld/ELF/LTO.h b/lld/ELF/LTO.h index acf3bcff7f2f1..c8cb2156d90ca 100644 --- a/lld/ELF/LTO.h +++ b/lld/ELF/LTO.h @@ -43,6 +43,7 @@ class BitcodeCompiler { void add(BitcodeFile &f); SmallVector<std::unique_ptr<InputFile>, 0> compile(); + void setBitcodeLibFuncs(ArrayRef<StringRef> bitcodeLibFuncs); private: Ctx &ctx; diff --git a/lld/test/COFF/lto-libcall-archive-bitcode.test b/lld/test/COFF/lto-libcall-archive-bitcode.test new file mode 100644 index 0000000000000..bd172f1ff3955 --- /dev/null +++ b/lld/test/COFF/lto-libcall-archive-bitcode.test @@ -0,0 +1,51 @@ +; REQUIRES: x86 + +; RUN: rm -rf %t && split-file %s %t && cd %t +; RUN: llvm-as main.ll -o main.obj +; RUN: llvm-as puts.ll -o puts.obj +; RUN: llvm-mc -filetype=obj -triple=x86_64-pc-windows-msvc printf.s -o printf.obj +; RUN: llvm-ar rcs libc.lib puts.obj printf.obj + +;; Ensure that no printf->puts translation occurs during LTO because puts is in +;; bitcode, but was not brought into the link. This would fail the link by +;; extracting bitcode after LTO. +; RUN: lld-link -out:out.exe -entry:main -subsystem:console -lldmap:- -nodefaultlib main.obj libc.lib | FileCheck %s + +;; Test the same behavior with lazy objects. +; RUN: lld-link -out:out-lazy.exe -entry:main -subsystem:console -lldmap:- -nodefaultlib main.obj /start-lib puts.obj /end-lib printf.obj | FileCheck %s + +;; Test that translation DOES occur when puts is extracted and brought into the link. +; RUN: lld-link -out:out-extracted.exe -entry:main -subsystem:console -lldmap:- -nodefaultlib main.obj puts.obj printf.obj | FileCheck %s --check-prefix=EXTRACTED + +; CHECK-NOT: puts +; CHECK: printf + +; EXTRACTED: printf +; EXTRACTED: puts + +;--- puts.ll +target datalayout = "e-m:w-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128" +target triple = "x86_64-pc-windows-msvc" + +define i32 @puts(ptr nocapture readonly %0) noinline { + call void asm sideeffect "", ""() + ret i32 0 +} + +;--- printf.s +.globl printf +printf: + ret + +;--- main.ll +target datalayout = "e-m:w-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128" +target triple = "x86_64-pc-windows-msvc" + +@str = constant [5 x i8] c"foo\0A\00" + +define i32 @main() { + %call = call i32 (ptr, ...) @printf(ptr @str) + ret i32 0 +} + +declare i32 @printf(ptr, ...) diff --git a/lld/test/ELF/lto/libcall-archive-bitcode.test b/lld/test/ELF/lto/libcall-archive-bitcode.test new file mode 100644 index 0000000000000..00726a2e6aeb5 --- /dev/null +++ b/lld/test/ELF/lto/libcall-archive-bitcode.test @@ -0,0 +1,54 @@ +; REQUIRES: x86 + +; RUN: rm -rf %t && split-file %s %t && cd %t +; RUN: llvm-as main.ll -o main.o +; RUN: llvm-as puts.ll -o puts.o +; RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux-gnu printf.s -o printf.o +; RUN: llvm-ar rcs libc.a puts.o printf.o + +;; Ensure that no printf->puts translation occurs during LTO because puts is in +;; bitcode, but was not brought into the link. This would fail the link by +;; extracting bitcode after LTO. +; RUN: ld.lld -o out main.o libc.a +; RUN: llvm-nm out | FileCheck %s + +;; Test the same behavior with lazy objects. +; RUN: ld.lld -o out-lazy main.o --start-lib puts.o --end-lib printf.o +; RUN: llvm-nm out-lazy | FileCheck %s + +;; Test that translation DOES occur when puts is extracted and brought into the link. +; RUN: ld.lld -o out-extracted main.o puts.o printf.o +; RUN: llvm-nm out-extracted | FileCheck %s --check-prefix=EXTRACTED + +; CHECK-NOT: puts +; CHECK: printf + +; EXTRACTED: printf +; EXTRACTED: puts + +;--- puts.ll +target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128" +target triple = "x86_64-unknown-linux-gnu" + +define i32 @puts(ptr nocapture readonly %0) noinline { + call void asm sideeffect "", ""() + ret i32 0 +} + +;--- printf.s +.globl printf +printf: + ret + +;--- main.ll +target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128" +target triple = "x86_64-unknown-linux-gnu" + +@str = constant [5 x i8] c"foo\0A\00" + +define i32 @_start() { + %call = call i32 (ptr, ...) @printf(ptr @str) + ret i32 0 +} + +declare i32 @printf(ptr, ...) diff --git a/lld/test/wasm/lto/libcall-archive-bitcode.ll b/lld/test/wasm/lto/libcall-archive-bitcode.ll new file mode 100644 index 0000000000000..3b640efc1091f --- /dev/null +++ b/lld/test/wasm/lto/libcall-archive-bitcode.ll @@ -0,0 +1,56 @@ +; REQUIRES: x86 + +; RUN: rm -rf %t && split-file %s %t && cd %t +; RUN: llvm-as main.ll -o main.o +; RUN: llvm-as puts.ll -o puts.o +; RUN: llvm-mc -filetype=obj -triple=wasm32-unknown-unknown printf.s -o printf.o +; RUN: llvm-ar rcs libc.a puts.o printf.o + +;; Ensure that no printf->puts translation occurs during LTO because puts is in +;; bitcode, but was not brought into the link. This would fail the link by +;; extracting bitcode after LTO. +; RUN: wasm-ld -o out.wasm main.o libc.a +; RUN: obj2yaml out.wasm | FileCheck %s + +;; Test the same behavior with lazy objects. +; RUN: wasm-ld -o out-lazy.wasm main.o --start-lib puts.o --end-lib printf.o +; RUN: obj2yaml out-lazy.wasm | FileCheck %s + +;; Test that translation DOES occur when puts is extracted and brought into the link. +; RUN: wasm-ld -o out-extracted.wasm main.o puts.o printf.o +; RUN: obj2yaml out-extracted.wasm | FileCheck %s --check-prefix=EXTRACTED + +; CHECK-NOT: Name: puts +; CHECK: Name: printf + +; EXTRACTED: Name: puts +; EXTRACTED-NOT: Name: printf + +;--- puts.ll +target datalayout = "e-m:e-p:32:32-p10:8:8-p20:8:8-i64:64-n32:64-S128-ni:1:10:20" +target triple = "wasm32-unknown-unknown" + +define i32 @puts(ptr nocapture readonly %0) noinline { + call void asm sideeffect "", ""() + ret i32 0 +} + +;--- printf.s +.globl printf +printf: + .functype printf (i32, i32) -> (i32) + i32.const 0 + end_function + +;--- main.ll +target datalayout = "e-m:e-p:32:32-p10:8:8-p20:8:8-i64:64-n32:64-S128-ni:1:10:20" +target triple = "wasm32-unknown-unknown" + +@str = constant [5 x i8] c"foo\0A\00" + +define i32 @_start() { + %call = call i32 (ptr, ...) @printf(ptr @str) + ret i32 0 +} + +declare i32 @printf(ptr, ...) \ No newline at end of file diff --git a/lld/wasm/LTO.cpp b/lld/wasm/LTO.cpp index 9fcb95b84b545..2c068bf518905 100644 --- a/lld/wasm/LTO.cpp +++ b/lld/wasm/LTO.cpp @@ -195,6 +195,10 @@ static void thinLTOCreateEmptyIndexFiles() { } } +void BitcodeCompiler::setBitcodeLibFuncs(ArrayRef<StringRef> bitcodeLibFuncs) { + ltoObj->setBitcodeLibFuncs(bitcodeLibFuncs); +} + // Merge all the bitcode files we have seen, codegen the result // and return the resulting objects. SmallVector<InputFile *, 0> BitcodeCompiler::compile() { diff --git a/lld/wasm/LTO.h b/lld/wasm/LTO.h index 21b1d59024663..6fa110d6099bf 100644 --- a/lld/wasm/LTO.h +++ b/lld/wasm/LTO.h @@ -46,6 +46,7 @@ class BitcodeCompiler { void add(BitcodeFile &f); SmallVector<InputFile *, 0> compile(); + void setBitcodeLibFuncs(ArrayRef<StringRef> bitcodeLibFuncs); private: std::unique_ptr<llvm::lto::LTO> ltoObj; diff --git a/lld/wasm/SymbolTable.cpp b/lld/wasm/SymbolTable.cpp index 05e653ea23eda..93d3e5f71a3e5 100644 --- a/lld/wasm/SymbolTable.cpp +++ b/lld/wasm/SymbolTable.cpp @@ -82,8 +82,31 @@ void SymbolTable::compileBitcodeFiles() { // Prevent further LTO objects being included BitcodeFile::doneLTO = true; + // Collect the bitcode library functions that are not safe to call because + // they were not yet brought in the link. (Such symbols are lazy.) + llvm::BumpPtrAllocator alloc; + llvm::StringSaver saver(alloc); + SmallVector<StringRef> bitcodeLibFuncs; + if (!ctx.bitcodeFiles.empty()) { + // Triple must be captured before the bitcode is moved into the compiler. + // Note that the below assumes that the set of possible libfuncs is + // equivalent for all bitcode translation units. + llvm::Triple tt = + llvm::Triple(ctx.bitcodeFiles.front()->obj->getTargetTriple()); + for (StringRef libFunc : llvm::lto::LTO::getLibFuncSymbols(tt, saver)) { + if (Symbol *sym = find(libFunc)) { + if (auto *lazy = dyn_cast<LazySymbol>(sym)) { + if (isa<BitcodeFile>(lazy->getFile())) + bitcodeLibFuncs.push_back(libFunc); + } + } + } + } + // Compile bitcode files and replace bitcode symbols. lto.reset(new BitcodeCompiler); + lto->setBitcodeLibFuncs(bitcodeLibFuncs); + for (BitcodeFile *f : ctx.bitcodeFiles) lto->add(*f); diff --git a/llvm/docs/ReleaseNotes.md b/llvm/docs/ReleaseNotes.md index d0d8b9f4ddabc..701b386dba73e 100644 --- a/llvm/docs/ReleaseNotes.md +++ b/llvm/docs/ReleaseNotes.md @@ -101,6 +101,13 @@ Changes to LLVM infrastructure this may fail if symlink permissions are not available. * Added ``readlink``, which reads the target of a symbolic link. +* Bitcode libraries can now implement compiler-managed library functions + (libcalls) without causing incorrect API manipulation or undefined references + ([#177046](https://github.com/llvm/llvm-project/pull/125687)). Note that + there are still issues with invalid compiler reasoning about some functions + in bitcode, e.g. `malloc`. Not yet supported on MachO or when using + distributed ThinLTO. + Changes to building LLVM ------------------------ diff --git a/llvm/include/llvm/LTO/LTO.h b/llvm/include/llvm/LTO/LTO.h index 3fec06b8bd78d..aba2661e81c47 100644 --- a/llvm/include/llvm/LTO/LTO.h +++ b/llvm/include/llvm/LTO/LTO.h @@ -179,7 +179,8 @@ class InputFile { // may emit references to. Such symbols must be considered external, as // removing them or modifying their interfaces would invalidate the code // generator's knowledge about them. - bool isLibcall(const RTLIB::RuntimeLibcallsInfo &Libcalls) const; + bool isLibcall(const TargetLibraryInfo &TLI, + const RTLIB::RuntimeLibcallsInfo &Libcalls) const; }; /// A range over the symbols in this InputFile. @@ -308,7 +309,8 @@ class ThinBackendProc { using ThinBackendFunction = std::function<std::unique_ptr<ThinBackendProc>( const Config &C, ModuleSummaryIndex &CombinedIndex, const DenseMap<StringRef, GVSummaryMapTy> &ModuleToDefinedGVSummaries, - AddStreamFn AddStream, FileCache Cache)>; + AddStreamFn AddStream, FileCache Cache, + ArrayRef<StringRef> BitcodeLibFuncs)>; /// This type defines the behavior following the thin-link phase during ThinLTO. /// It encapsulates a backend function and a strategy for thread pool @@ -323,10 +325,11 @@ struct ThinBackend { std::unique_ptr<ThinBackendProc> operator()( const Config &Conf, ModuleSummaryIndex &CombinedIndex, const DenseMap<StringRef, GVSummaryMapTy> &ModuleToDefinedGVSummaries, - AddStreamFn AddStream, FileCache Cache) { + AddStreamFn AddStream, FileCache Cache, + ArrayRef<StringRef> BitcodeLibFuncs) { assert(isValid() && "Invalid backend function"); return Func(Conf, CombinedIndex, ModuleToDefinedGVSummaries, - std::move(AddStream), std::move(Cache)); + std::move(AddStream), std::move(Cache), BitcodeLibFuncs); } ThreadPoolStrategy getParallelism() const { return Parallelism; } bool isValid() const { return static_cast<bool>(Func); } @@ -446,6 +449,11 @@ class LTO { LLVM_ABI Error add(std::unique_ptr<InputFile> Obj, ArrayRef<SymbolResolution> Res); + /// Set the list of functions implemented in bitcode that were not extracted + /// from an archive. Such functions may not be referenced, as they have + /// lost their opportunity to be defined. + LLVM_ABI void setBitcodeLibFuncs(ArrayRef<StringRef> BitcodeLibFuncs); + /// Returns an upper bound on the number of tasks that the client may expect. /// This may only be called after all IR object files have been added. For a /// full description of tasks see LTOBackend.h. @@ -466,6 +474,14 @@ class LTO { LLVM_ABI static SmallVector<const char *> getRuntimeLibcallSymbols(const Triple &TT); + /// Static method that returns a list of library function symbols that can be + /// generated by LTO but might not be visible from bitcode symbol table. + /// Unlike the runtime libcalls, the linker can report to the code generator + /// which of these are actually available in the link, and the code generator + /// can then only reference that set of symbols. + LLVM_ABI static SmallVector<StringRef> + getLibFuncSymbols(const Triple &TT, llvm::StringSaver &Saver); + protected: // Called at the start of run(). virtual Error serializeInputsForDistribution() { return Error::success(); } @@ -657,6 +673,11 @@ class LTO { // Setup optimization remarks according to the provided configuration. Error setupOptimizationRemarks(); + // LibFuncs that were implemented in bitcode but were not extracted + // from their libraries. Such functions cannot safely be called, since + // they have lost their opportunity to be defined. + SmallVector<StringRef> BitcodeLibFuncs; + public: /// Helper to emit an optimization remark during the LTO link when outside of /// the standard optimization pass pipeline. diff --git a/llvm/include/llvm/LTO/LTOBackend.h b/llvm/include/llvm/LTO/LTOBackend.h index 48ad5aa64f61f..4bb38529ec754 100644 --- a/llvm/include/llvm/LTO/LTOBackend.h +++ b/llvm/include/llvm/LTO/LTOBackend.h @@ -39,13 +39,15 @@ LLVM_ABI bool opt(const Config &Conf, TargetMachine *TM, unsigned Task, Module &Mod, bool IsThinLTO, ModuleSummaryIndex *ExportSummary, const ModuleSummaryIndex *ImportSummary, - const std::vector<uint8_t> &CmdArgs); + const std::vector<uint8_t> &CmdArgs, + ArrayRef<StringRef> BitcodeLibFuncs); /// Runs a regular LTO backend. The regular LTO backend can also act as the /// regular LTO phase of ThinLTO, which may need to access the combined index. LLVM_ABI Error backend(const Config &C, AddStreamFn AddStream, unsigned ParallelCodeGenParallelismLevel, Module &M, - ModuleSummaryIndex &CombinedIndex); + ModuleSummaryIndex &CombinedIndex, + ArrayRef<StringRef> BitcodeLibFuncs); /// Runs a ThinLTO backend. /// If \p ModuleMap is not nullptr, all the module files to be imported have @@ -56,14 +58,14 @@ LLVM_ABI Error backend(const Config &C, AddStreamFn AddStream, /// the backend will skip optimization and only perform code generation. If /// \p IRAddStream is not nullptr, it will be called just before code generation /// to serialize the optimized IR. -LLVM_ABI Error -thinBackend(const Config &C, unsigned Task, AddStreamFn AddStream, Module &M, - const ModuleSummaryIndex &CombinedIndex, - const FunctionImporter::ImportMapTy &ImportList, - const GVSummaryMapTy &DefinedGlobals, - MapVector<StringRef, BitcodeModule> *ModuleMap, bool CodeGenOnly, - AddStreamFn IRAddStream = nullptr, - const std::vector<uint8_t> &CmdArgs = std::vector<uint8_t>()); +LLVM_ABI Error thinBackend( + const Config &C, unsigned Task, AddStreamFn AddStream, Module &M, + const ModuleSummaryIndex &CombinedIndex, + const FunctionImporter::ImportMapTy &ImportList, + const GVSummaryMapTy &DefinedGlobals, + MapVector<StringRef, BitcodeModule> *ModuleMap, bool CodeGenOnly, + ArrayRef<StringRef> BitcodeLibFuncs, AddStreamFn IRAddStream = nullptr, + const std::vector<uint8_t> &CmdArgs = std::vector<uint8_t>()); LLVM_ABI Error finalizeOptimizationRemarks(LLVMRemarkFileHandle DiagOutputFile); diff --git a/llvm/lib/LTO/LTO.cpp b/llvm/lib/LTO/LTO.cpp index 1a6976eea8088..95faf3484c456 100644 --- a/llvm/lib/LTO/LTO.cpp +++ b/llvm/lib/LTO/LTO.cpp @@ -653,7 +653,11 @@ Expected<std::unique_ptr<InputFile>> InputFile::create(MemoryBufferRef Object) { } bool InputFile::Symbol::isLibcall( + const TargetLibraryInfo &TLI, const RTLIB::RuntimeLibcallsInfo &Libcalls) const { + LibFunc F; + if (TLI.getLibFunc(IRName, F) && TLI.has(F)) + return true; return Libcalls.getSupportedLibcallImpl(IRName) != RTLIB::Unsupported; } @@ -715,6 +719,8 @@ void LTO::addModuleToGlobalRes(ArrayRef<InputFile::Symbol> Syms, auto *ResE = Res.end(); (void)ResE; RTLIB::RuntimeLibcallsInfo Libcalls(TT); + TargetLibraryInfoImpl TLII(TT); + TargetLibraryInfo TLI(TLII); for (const InputFile::Symbol &Sym : Syms) { assert(ResI != ResE); SymbolResolution Res = *ResI++; @@ -757,7 +763,7 @@ void LTO::addModuleToGlobalRes(ArrayRef<InputFile::Symbol> Syms, GlobalRes.VisibleOutsideSummary = true; } - bool IsLibcall = Sym.isLibcall(Libcalls); + bool IsLibcall = Sym.isLibcall(TLI, Libcalls); // Set the partition to external if we know it is re-defined by the linker // with -defsym or -wrap options, used elsewhere, e.g. it is visible to a @@ -844,6 +850,12 @@ Error LTO::add(std::unique_ptr<InputFile> InputPtr, return Error::success(); } +void LTO::setBitcodeLibFuncs(ArrayRef<StringRef> BitcodeLibFuncs) { + assert(this->BitcodeLibFuncs.empty() && + "bitcode libfuncs were set twice; maybe accidentally clobbered?"); + this->BitcodeLibFuncs.append(BitcodeLibFuncs.begin(), BitcodeLibFuncs.end()); +} + Expected<ArrayRef<SymbolResolution>> LTO::addModule(InputFile &Input, ArrayRef<SymbolResolution> InputRes, unsigned ModI, ArrayRef<SymbolResolution> Res) { @@ -1469,9 +1481,9 @@ Error LTO::runRegularLTO(AddStreamFn AddStream) { } if (!RegularLTO.EmptyCombinedModule || Conf.AlwaysEmitRegularLTOObj) { - if (Error Err = - backend(Conf, AddStream, RegularLTO.ParallelCodeGenParallelismLevel, - *RegularLTO.CombinedModule, ThinLTO.CombinedIndex)) + if (Error Err = backend( + Conf, AddStream, RegularLTO.ParallelCodeGenParallelismLevel, + *RegularLTO.CombinedModule, ThinLTO.CombinedIndex, BitcodeLibFuncs)) return Err; } @@ -1491,6 +1503,20 @@ SmallVector<const char *> LTO::getRuntimeLibcallSymbols(const Triple &TT) { return LibcallSymbols; } +SmallVector<StringRef> LTO::getLibFuncSymbols(const Triple &TT, + StringSaver &Saver) { + auto TLII = std::make_unique<TargetLibraryInfoImpl>(TT); + TargetLibraryInfo TLI(*TLII); + SmallVector<StringRef> LibFuncSymbols; + LibFuncSymbols.reserve(LibFunc::NumLibFuncs); + for (unsigned I = LibFunc::Begin_LibFunc; I != LibFunc::End_LibFunc; ++I) { + LibFunc F = static_cast<LibFunc>(I); + if (TLI.has(F)) + LibFuncSymbols.push_back(Saver.save(TLI.getName(F)).data()); + } + return LibFuncSymbols; +} + Error ThinBackendProc::emitFiles( const FunctionImporter::ImportMapTy &ImportList, llvm::StringRef ModulePath, const std::string &NewModulePath) const { @@ -1568,6 +1594,7 @@ class InProcessThinBackend : public CGThinBackend { // generating directly into the returned output stream. AddStreamFn AddStream; FileCache Cache; + ArrayRef<StringRef> BitcodeLibFuncs; public: InProcessThinBackend( @@ -1575,11 +1602,13 @@ class InProcessThinBackend : public CGThinBackend { ThreadPoolStrategy ThinLTOParallelism, const DenseMap<StringRef, GVSummaryMapTy> &ModuleToDefinedGVSummaries, AddStreamFn AddStream, FileCache Cache, lto::IndexWriteCallback OnWrite, - bool ShouldEmitIndexFiles, bool ShouldEmitImportsFiles) + bool ShouldEmitIndexFiles, bool ShouldEmitImportsFiles, + ArrayRef<StringRef> BitcodeLibFuncs) : CGThinBackend(Conf, CombinedIndex, ModuleToDefinedGVSummaries, OnWrite, ShouldEmitIndexFiles, ShouldEmitImportsFiles, ThinLTOParallelism), - AddStream(std::move(AddStream)), Cache(std::move(Cache)) {} + AddStream(std::move(AddStream)), Cache(std::move(Cache)), + BitcodeLibFuncs(BitcodeLibFuncs) {} virtual Error runThinLTOBackendThread( AddStreamFn AddStream, FileCache Cache, unsigned Task, BitcodeModule BM, @@ -1600,7 +1629,7 @@ class InProcessThinBackend : public CGThinBackend { return thinBackend(Conf, Task, AddStream, **MOrErr, CombinedIndex, ImportList, DefinedGlobals, &ModuleMap, - Conf.CodeGenOnly); + Conf.CodeGenOnly, BitcodeLibFuncs); }; if (ShouldEmitIndexFiles) { if (auto E = emitFiles(ImportList, ModuleID, ModuleID.str())) @@ -1685,13 +1714,14 @@ class FirstRoundThinBackend : public InProcessThinBackend { const Config &Conf, ModuleSummaryIndex &CombinedIndex, ThreadPoolStrategy ThinLTOParallelism, const DenseMap<StringRef, GVSummaryMapTy> &ModuleToDefinedGVSummaries, - AddStreamFn CGAddStream, FileCache CGCache, AddStreamFn IRAddStream, + AddStreamFn CGAddStream, FileCache CGCache, + ArrayRef<StringRef> BitcodeLibFuncs, AddStreamFn IRAddStream, FileCache IRCache) : InProcessThinBackend(Conf, CombinedIndex, ThinLTOParallelism, ModuleToDefinedGVSummaries, std::move(CGAddStream), std::move(CGCache), /*OnWrite=*/nullptr, /*ShouldEmitIndexFiles=*/false, - /*ShouldEmitImportsFiles=*/false), + /*ShouldEmitImportsFiles=*/false, BitcodeLibFuncs), IRAddStream(std::move(IRAddStream)), IRCache(std::move(IRCache)) {} Error runThinLTOBackendThread( @@ -1714,7 +1744,7 @@ class FirstRoundThinBackend : public InProcessThinBackend { return thinBackend(Conf, Task, CGAddStream, **MOrErr, CombinedIndex, ImportList, DefinedGlobals, &ModuleMap, - Conf.CodeGenOnly, IRAddStream); + Conf.CodeGenOnly, BitcodeLibFuncs, IRAddStream); }; // Like InProcessThinBackend, we produce index files as needed for // FirstRoundThinBackend. However, these files are not generated for @@ -1781,6 +1811,7 @@ class SecondRoundThinBackend : public InProcessThinBackend { ThreadPoolStrategy ThinLTOParallelism, const DenseMap<StringRef, GVSummaryMapTy> &ModuleToDefinedGVSummaries, AddStreamFn AddStream, FileCache Cache, + ArrayRef<StringRef> BitcodeLibFuncs, std::unique_ptr<SmallVector<StringRef>> IRFiles, stable_hash CombinedCGDataHash) : InProcessThinBackend(Conf, CombinedIndex, ThinLTOParallelism, @@ -1788,7 +1819,7 @@ class SecondRoundThinBackend : public InProcessThinBackend { std::move(Cache), /*OnWrite=*/nullptr, /*ShouldEmitIndexFiles=*/false, - /*ShouldEmitImportsFiles=*/false), + /*ShouldEmitImportsFiles=*/false, BitcodeLibFuncs), IRFiles(std::move(IRFiles)), CombinedCGDataHash(CombinedCGDataHash) {} Error runThinLTOBackendThread( @@ -1809,7 +1840,7 @@ class SecondRoundThinBackend : public InProcessThinBackend { return thinBackend(Conf, Task, AddStream, *LoadedModule, CombinedIndex, ImportList, DefinedGlobals, &ModuleMap, - /*CodeGenOnly=*/true); + /*CodeGenOnly=*/true, BitcodeLibFuncs); }; if (!Cache.isValid() || !CombinedIndex.modulePaths().count(ModuleID) || all_of(CombinedIndex.getModuleHash(ModuleID), @@ -1848,11 +1879,12 @@ ThinBackend lto::createInProcessThinBackend(ThreadPoolStrategy Parallelism, auto Func = [=](const Config &Conf, ModuleSummaryIndex &CombinedIndex, const DenseMap<StringRef, GVSummaryMapTy> &ModuleToDefinedGVSummaries, - AddStreamFn AddStream, FileCache Cache) { + AddStreamFn AddStream, FileCache Cache, + ArrayRef<StringRef> BitcodeLibFuncs) { return std::make_unique<InProcessThinBackend>( Conf, CombinedIndex, Parallelism, ModuleToDefinedGVSummaries, AddStream, Cache, OnWrite, ShouldEmitIndexFiles, - ShouldEmitImportsFiles); + ShouldEmitImportsFiles, BitcodeLibFuncs); }; return ThinBackend(Func, Parallelism); } @@ -1969,7 +2001,8 @@ ThinBackend lto::createWriteIndexesThinBackend( auto Func = [=](const Config &Conf, ModuleSummaryIndex &CombinedIndex, const DenseMap<StringRef, GVSummaryMapTy> &ModuleToDefinedGVSummaries, - AddStreamFn AddStream, FileCache Cache) { + AddStreamFn AddStream, FileCache Cache, + ArrayRef<StringRef> BitcodeLibFuncs) { return std::make_unique<WriteIndexesThinBackend>( Conf, CombinedIndex, Parallelism, ModuleToDefinedGVSummaries, OldPrefix, NewPrefix, NativeObjectPrefix, ShouldEmitImportsFiles, @@ -2222,7 +2255,7 @@ Error LTO::runThinLTO(AddStreamFn AddStream, FileCache Cache, if (!CodeGenDataThinLTOTwoRounds) { std::unique_ptr<ThinBackendProc> BackendProc = ThinLTO.Backend(Conf, ThinLTO.CombinedIndex, ModuleToDefinedGVSummaries, - AddStream, Cache); + AddStream, Cache, BitcodeLibFuncs); return RunBackends(BackendProc.get()); } @@ -2245,7 +2278,7 @@ Error LTO::runThinLTO(AddStreamFn AddStream, FileCache Cache, LLVM_DEBUG(dbgs() << "[TwoRounds] Running the first round of codegen\n"); auto FirstRoundLTO = std::make_unique<FirstRoundThinBackend>( Conf, ThinLTO.CombinedIndex, Parallelism, ModuleToDefinedGVSummaries, - CG.AddStream, CG.Cache, IR.AddStream, IR.Cache); + CG.AddStream, CG.Cache, BitcodeLibFuncs, IR.AddStream, IR.Cache); if (Error E = RunBackends(FirstRoundLTO.get())) return E; @@ -2261,7 +2294,7 @@ Error LTO::runThinLTO(AddStreamFn AddStream, FileCache Cache, LLVM_DEBUG(dbgs() << "[TwoRounds] Running the second round of codegen\n"); auto SecondRoundLTO = std::make_unique<SecondRoundThinBackend>( Conf, ThinLTO.CombinedIndex, Parallelism, ModuleToDefinedGVSummaries, - AddStream, Cache, IR.getResult(), CombinedHash); + AddStream, Cache, BitcodeLibFuncs, IR.getResult(), CombinedHash); return RunBackends(SecondRoundLTO.get()); } @@ -2768,7 +2801,7 @@ ThinBackend lto::createOutOfProcessThinBackend( auto Func = [=](const Config &Conf, ModuleSummaryIndex &CombinedIndex, const DenseMap<StringRef, GVSummaryMapTy> &ModuleToDefinedGVSummaries, - AddStreamFn, FileCache Cache) { + AddStreamFn, FileCache Cache, ArrayRef<StringRef> BitcodeLibFuncs) { return std::make_unique<OutOfProcessThinBackend>( Conf, CombinedIndex, Parallelism, ModuleToDefinedGVSummaries, Cache, OnWrite, ShouldEmitIndexFiles, ShouldEmitImportsFiles, diff --git a/llvm/lib/LTO/LTOBackend.cpp b/llvm/lib/LTO/LTOBackend.cpp index 7ee2557a68bd5..16a42e526eb8a 100644 --- a/llvm/lib/LTO/LTOBackend.cpp +++ b/llvm/lib/LTO/LTOBackend.cpp @@ -259,7 +259,8 @@ createTargetMachine(const Config &Conf, const Target *TheTarget, Module &M) { static void runNewPMPasses(const Config &Conf, Module &Mod, TargetMachine *TM, unsigned OptLevel, bool IsThinLTO, ModuleSummaryIndex *ExportSummary, - const ModuleSummaryIndex *ImportSummary) { + const ModuleSummaryIndex *ImportSummary, + const DenseSet<StringRef> &BitcodeLibFuncs) { std::optional<PGOOptions> PGOOpt; if (!Conf.SampleProfile.empty()) PGOOpt = PGOOptions(Conf.SampleProfile, "", Conf.ProfileRemapping, @@ -301,6 +302,20 @@ static void runNewPMPasses(const Config &Conf, Module &Mod, TargetMachine *TM, new TargetLibraryInfoImpl(TM->getTargetTriple(), TM->Options.VecLib)); if (Conf.Freestanding) TLII->disableAllFunctions(); + + // Determine whether or not its safe to emit calls to each libfunc. Libfuncs + // that might have been present in the current LTO unit, but are not, have + // lost their only opportunity to be defined, and calls must not be emitted to + // them. + // FIXME: BitcodeLibFuncs isn't yet set for distributed ThinLTO. + TargetLibraryInfo TLI(*TLII); + for (unsigned I = 0, E = static_cast<unsigned>(LibFunc::NumLibFuncs); I != E; + ++I) { + LibFunc F = static_cast<LibFunc>(I); + if (BitcodeLibFuncs.contains(TLI.getName(F))) + TLII->setUnavailable(F); + } + FAM.registerPass([&] { return TargetLibraryAnalysis(*TLII); }); // Parse a custom AA pipeline if asked to. @@ -384,7 +399,8 @@ static bool isEmptyModule(const Module &Mod) { bool lto::opt(const Config &Conf, TargetMachine *TM, unsigned Task, Module &Mod, bool IsThinLTO, ModuleSummaryIndex *ExportSummary, const ModuleSummaryIndex *ImportSummary, - const std::vector<uint8_t> &CmdArgs) { + const std::vector<uint8_t> &CmdArgs, + ArrayRef<StringRef> BitcodeLibFuncs) { llvm::TimeTraceScope timeScope("opt"); if (EmbedBitcode == LTOBitcodeEmbedding::EmbedPostMergePreOptimized) { // FIXME: the motivation for capturing post-merge bitcode and command line @@ -409,9 +425,11 @@ bool lto::opt(const Config &Conf, TargetMachine *TM, unsigned Task, Module &Mod, // analysis in the case of a ThinLTO build where this might be an empty // regular LTO combined module, with a large combined index from ThinLTO. if (!isEmptyModule(Mod)) { + DenseSet<StringRef> BitcodeLibFuncsSet(BitcodeLibFuncs.begin(), + BitcodeLibFuncs.end()); // FIXME: Plumb the combined index into the new pass manager. runNewPMPasses(Conf, Mod, TM, Conf.OptLevel, IsThinLTO, ExportSummary, - ImportSummary); + ImportSummary, BitcodeLibFuncsSet); } return !Conf.PostOptModuleHook || Conf.PostOptModuleHook(Task, Mod); } @@ -577,7 +595,8 @@ Error lto::finalizeOptimizationRemarks(LLVMRemarkFileHandle DiagOutputFile) { Error lto::backend(const Config &C, AddStreamFn AddStream, unsigned ParallelCodeGenParallelismLevel, Module &Mod, - ModuleSummaryIndex &CombinedIndex) { + ModuleSummaryIndex &CombinedIndex, + ArrayRef<StringRef> BitcodeLibFuncs) { llvm::TimeTraceScope timeScope("LTO backend"); Expected<const Target *> TOrErr = initAndLookupTarget(C, Mod); if (!TOrErr) @@ -589,7 +608,7 @@ Error lto::backend(const Config &C, AddStreamFn AddStream, if (!C.CodeGenOnly) { if (!opt(C, TM.get(), 0, Mod, /*IsThinLTO=*/false, /*ExportSummary=*/&CombinedIndex, /*ImportSummary=*/nullptr, - /*CmdArgs*/ std::vector<uint8_t>())) + /*CmdArgs*/ std::vector<uint8_t>(), BitcodeLibFuncs)) return Error::success(); } @@ -629,7 +648,8 @@ Error lto::thinBackend(const Config &Conf, unsigned Task, AddStreamFn AddStream, const FunctionImporter::ImportMapTy &ImportList, const GVSummaryMapTy &DefinedGlobals, MapVector<StringRef, BitcodeModule> *ModuleMap, - bool CodeGenOnly, AddStreamFn IRAddStream, + bool CodeGenOnly, ArrayRef<StringRef> BitcodeLibFuncs, + AddStreamFn IRAddStream, const std::vector<uint8_t> &CmdArgs) { llvm::TimeTraceScope timeScope("Thin backend", Mod.getModuleIdentifier()); Expected<const Target *> TOrErr = initAndLookupTarget(Conf, Mod); @@ -668,7 +688,7 @@ Error lto::thinBackend(const Config &Conf, unsigned Task, AddStreamFn AddStream, // Perform optimization and code generation for ThinLTO. if (!opt(Conf, TM, Task, Mod, /*IsThinLTO=*/true, /*ExportSummary=*/nullptr, /*ImportSummary=*/&CombinedIndex, - CmdArgs)) + CmdArgs, BitcodeLibFuncs)) return finalizeOptimizationRemarks(std::move(DiagnosticOutputFile)); // Save the current module before the first codegen round. diff --git a/llvm/lib/LTO/LTOCodeGenerator.cpp b/llvm/lib/LTO/LTOCodeGenerator.cpp index 46be71da5a092..8b9bcfb1d4736 100644 --- a/llvm/lib/LTO/LTOCodeGenerator.cpp +++ b/llvm/lib/LTO/LTOCodeGenerator.cpp @@ -614,7 +614,7 @@ bool LTOCodeGenerator::optimize() { TargetMach = createTargetMachine(); if (!opt(Config, TargetMach.get(), 0, *MergedModule, /*IsThinLTO=*/false, /*ExportSummary=*/&CombinedIndex, /*ImportSummary=*/nullptr, - /*CmdArgs*/ std::vector<uint8_t>())) { + /*CmdArgs*/ std::vector<uint8_t>(), /*BitcodeLibFuncs=*/{})) { emitError("LTO middle-end optimizations failed"); return false; } @@ -639,7 +639,7 @@ bool LTOCodeGenerator::compileOptimized(AddStreamFn AddStream, Config.CodeGenOnly = true; Error Err = backend(Config, AddStream, ParallelismLevel, *MergedModule, - CombinedIndex); + CombinedIndex, /*BitcodeLibFuncs=*/{}); assert(!Err && "unexpected code-generation failure"); (void)Err; diff --git a/llvm/lib/LTO/ThinLTOCodeGenerator.cpp b/llvm/lib/LTO/ThinLTOCodeGenerator.cpp index 93b672ae7840c..6397fdffed687 100644 --- a/llvm/lib/LTO/ThinLTOCodeGenerator.cpp +++ b/llvm/lib/LTO/ThinLTOCodeGenerator.cpp @@ -292,8 +292,10 @@ addUsedSymbolToPreservedGUID(const lto::InputFile &File, DenseSet<GlobalValue::GUID> &PreservedGUID) { Triple TT(File.getTargetTriple()); RTLIB::RuntimeLibcallsInfo Libcalls(TT); + TargetLibraryInfoImpl TLII(TT); + TargetLibraryInfo TLI(TLII); for (const auto &Sym : File.symbols()) - if (Sym.isUsed() || Sym.isLibcall(Libcalls)) + if (Sym.isUsed() || Sym.isLibcall(TLI, Libcalls)) PreservedGUID.insert( GlobalValue::getGUIDAssumingExternalLinkage(Sym.getIRName())); } diff --git a/llvm/test/LTO/Resolution/X86/libcall-external.ll b/llvm/test/LTO/Resolution/X86/libcall-external.ll new file mode 100644 index 0000000000000..46756b387668c --- /dev/null +++ b/llvm/test/LTO/Resolution/X86/libcall-external.ll @@ -0,0 +1,25 @@ +;; When a libcall was not brought into the link, it can be used iff it is +;; defined in native code, not bitcode. +; RUN: opt %s -o %t.o -mtriple x86_64-unknown-linux-musl +; RUN: llvm-lto2 run -o %t.bitcode.o \ +; RUN: -r %t.o,foo,plx -r %t.o,memcmp,x -save-temps %t.o \ +; RUN: --bitcode-libfuncs=bcmp +; RUN: llvm-dis %t.bitcode.o.0.4.opt.bc -o - | FileCheck --check-prefixes=CHECK,BITCODE %s +; RUN: llvm-lto2 run -o %t.native.o \ +; RUN: -r %t.o,foo,plx -r %t.o,memcmp,x -save-temps %t.o +; RUN: llvm-dis %t.native.o.0.4.opt.bc -o - | FileCheck --check-prefixes=CHECK,NATIVE %s +define i1 @foo(ptr %0, ptr %1, i64 %2) { + ; CHECK-LABEL: define{{.*}}i1 @foo + ; BITCODE-NEXT: %cmp = {{.*}}call i32 @memcmp + ; BITCODE-NEXT: %eq = icmp eq i32 %cmp, 0 + ; NATIVE-NEXT: %bcmp = {{.*}}call i32 @bcmp + ; NATIVE-NEXT: %eq = icmp eq i32 %bcmp, 0 + ; CHECK-NEXT: ret i1 %eq + + + %cmp = call i32 @memcmp(ptr %0, ptr %1, i64 %2) + %eq = icmp eq i32 %cmp, 0 + ret i1 %eq +} + +declare i32 @memcmp(ptr, ptr, i64) diff --git a/llvm/test/LTO/Resolution/X86/libcall-in-thin-link.ll b/llvm/test/LTO/Resolution/X86/libcall-in-thin-link.ll new file mode 100644 index 0000000000000..fe8e492580d42 --- /dev/null +++ b/llvm/test/LTO/Resolution/X86/libcall-in-thin-link.ll @@ -0,0 +1,35 @@ +;; If a libcall was extracted in a thin link, it can be used even if not +;; present in the current TU. + +; RUN: rm -rf %t && split-file %s %t && cd %t +; RUN: opt foo.ll -o foo.o -module-summary -mtriple x86_64-unknown-linux-musl +; RUN: opt bcmp.ll -o bcmp.o -module-summary -mtriple x86_64-unknown-linux-musl +; RUN: llvm-lto2 run -o lto.o \ +; RUN: -r foo.o,foo,plx \ +; RUN: -r foo.o,memcmp,x \ +; RUN: -r bcmp.o,bcmp,pl \ +; RUN: -r bcmp.o,bcmp_impl,x foo.o bcmp.o -save-temps +; RUN: llvm-dis lto.o.1.4.opt.bc -o - | FileCheck %s + +;--- foo.ll +define i1 @foo(ptr %0, ptr %1, i64 %2) { + ; CHECK-LABEL: define{{.*}}i1 @foo + ; CHECK-NEXT: %bcmp = {{.*}}call i32 @bcmp + ; CHECK-NEXT: %eq = icmp eq i32 %bcmp, 0 + ; CHECK-NEXT: ret i1 %eq + + %cmp = call i32 @memcmp(ptr %0, ptr %1, i64 %2) + %eq = icmp eq i32 %cmp, 0 + ret i1 %eq +} + +declare i32 @memcmp(ptr, ptr, i64) + +;--- bcmp.ll +define i32 @bcmp(ptr %0, ptr %1, i64 %2) noinline { + %r = call i32 @bcmp_impl(ptr %0, ptr %1, i64 %2) + ret i32 %r +} + +declare i32 @bcmp_impl(ptr, ptr, i64) + diff --git a/llvm/test/LTO/Resolution/X86/libcall-in-tu.ll b/llvm/test/LTO/Resolution/X86/libcall-in-tu.ll new file mode 100644 index 0000000000000..cddf5d30697d0 --- /dev/null +++ b/llvm/test/LTO/Resolution/X86/libcall-in-tu.ll @@ -0,0 +1,34 @@ +;; This test comes from a real world scenario in LTO, where the definition of +;; bcmp was deleted because it has no uses, but later instcombine re-introduced +;; a call to bcmp() as part of SimplifyLibCalls. Such deletions must not be +;; allowed. + +; RUN: opt %s -o %t.o -mtriple x86_64-unknown-linux-musl +; RUN: llvm-lto2 run -o %t.lto.o \ +; RUN: -r %t.o,foo,plx \ +; RUN: -r %t.o,memcmp,x \ +; RUN: -r %t.o,bcmp,pl \ +; RUN: -r %t.o,bcmp_impl,x %t.o -save-temps +; RUN: llvm-dis %t.lto.o.0.4.opt.bc -o - | FileCheck %s + +define i1 @foo(ptr %0, ptr %1, i64 %2) { + ; CHECK-LABEL: define{{.*}}i1 @foo + ; CHECK-NEXT: %bcmp = {{.*}}call i32 @bcmp + ; CHECK-NEXT: %eq = icmp eq i32 %bcmp, 0 + ; CHECK-NEXT: ret i1 %eq + + %cmp = call i32 @memcmp(ptr %0, ptr %1, i64 %2) + %eq = icmp eq i32 %cmp, 0 + ret i1 %eq +} + +declare i32 @memcmp(ptr, ptr, i64) +declare i32 @bcmp_impl(ptr, ptr, i64) + +;; Ensure bcmp is not removed from module because it is external. +; CHECK: define dso_local i32 @bcmp +define i32 @bcmp(ptr %0, ptr %1, i64 %2) noinline { + %r = call i32 @bcmp_impl(ptr %0, ptr %1, i64 %2) + ret i32 %r +} + diff --git a/llvm/tools/llvm-lto2/llvm-lto2.cpp b/llvm/tools/llvm-lto2/llvm-lto2.cpp index 8c676251cb391..839324e396850 100644 --- a/llvm/tools/llvm-lto2/llvm-lto2.cpp +++ b/llvm/tools/llvm-lto2/llvm-lto2.cpp @@ -234,6 +234,19 @@ static cl::opt<bool> AllVtablesHaveTypeInfos("all-vtables-have-type-infos", cl::Hidden, cl::desc("All vtables have type infos")); +// Specifying a symbol here states that it is a library symbol that had a +// definition in bitcode, but was not extracted. Such symbols cannot safely +// be referenced, since they have already lost their opportunity to be defined. +// +// FIXME: Listing all bitcode libfunc symbols here is clunky. A higher-level way +// to indicate which TUs made it into the link might be better, but this would +// require more detailed tracking of the sources of constructs in the IR. +// Alternatively, there may be some other data structure that could hold this +// information. +static cl::list<std::string> BitcodeLibFuncs( + "bitcode-libfuncs", cl::Hidden, + cl::desc("set of unextracted libfuncs implemented in bitcode")); + static cl::opt<bool> TimeTrace("time-trace", cl::desc("Record time trace")); static cl::opt<unsigned> TimeTraceGranularity( @@ -514,6 +527,9 @@ static int run(int argc, char **argv) { if (HasErrors) return 1; + Lto.setBitcodeLibFuncs( + SmallVector<StringRef>(BitcodeLibFuncs.begin(), BitcodeLibFuncs.end())); + FileCache Cache; if (!CacheDir.empty()) Cache = check(localCache("ThinLTO", "Thin", CacheDir, AddBuffer), _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
