[llvm] r265113 - Add a libLTO API to stop/restart ThinLTO between optimizations and CodeGen
Benjamin Kramer via llvm-commits
llvm-commits at lists.llvm.org
Fri Apr 1 05:04:50 PDT 2016
On Fri, Apr 1, 2016 at 8:47 AM, Mehdi Amini via llvm-commits
<llvm-commits at lists.llvm.org> wrote:
> Author: mehdi_amini
> Date: Fri Apr 1 01:47:02 2016
> New Revision: 265113
>
> URL: http://llvm.org/viewvc/llvm-project?rev=265113&view=rev
> Log:
> Add a libLTO API to stop/restart ThinLTO between optimizations and CodeGen
>
> This allows the linker to instruct ThinLTO to perform only the
> optimization part or only the codegen part of the process.
Is there any way to test this? Currently this just adds dead code.
>
> From: Mehdi Amini <mehdi.amini at apple.com>
>
> Modified:
> llvm/trunk/include/llvm-c/lto.h
> llvm/trunk/include/llvm/LTO/ThinLTOCodeGenerator.h
> llvm/trunk/lib/LTO/ThinLTOCodeGenerator.cpp
> llvm/trunk/tools/lto/lto.cpp
> llvm/trunk/tools/lto/lto.exports
>
> Modified: llvm/trunk/include/llvm-c/lto.h
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm-c/lto.h?rev=265113&r1=265112&r2=265113&view=diff
> ==============================================================================
> --- llvm/trunk/include/llvm-c/lto.h (original)
> +++ llvm/trunk/include/llvm-c/lto.h Fri Apr 1 01:47:02 2016
> @@ -44,7 +44,8 @@ typedef bool lto_bool_t;
> * @{
> */
>
> -#define LTO_API_VERSION 18
> +#define LTO_API_VERSION 19
> +
> /**
> * \since prior to LTO_API_VERSION=3
> */
> @@ -718,6 +719,23 @@ extern void thinlto_codegen_set_savetemp
> extern void thinlto_codegen_set_cpu(thinlto_code_gen_t cg, const char *cpu);
>
> /**
> + * Disable CodeGen, only run the stages till codegen and stop. The output will
> + * be bitcode.
> + *
> + * \since LTO_API_VERSION=19
> + */
> +extern void thinlto_codegen_disable_codegen(thinlto_code_gen_t cg,
> + lto_bool_t disable);
> +
> +/**
> + * Perform CodeGen only: disable all other stages.
> + *
> + * \since LTO_API_VERSION=19
> + */
> +extern void thinlto_codegen_set_codegen_only(thinlto_code_gen_t cg,
> + lto_bool_t codegen_only);
> +
> +/**
> * Parse -mllvm style debug options.
> *
> * \since LTO_API_VERSION=18
>
> Modified: llvm/trunk/include/llvm/LTO/ThinLTOCodeGenerator.h
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/LTO/ThinLTOCodeGenerator.h?rev=265113&r1=265112&r2=265113&view=diff
> ==============================================================================
> --- llvm/trunk/include/llvm/LTO/ThinLTOCodeGenerator.h (original)
> +++ llvm/trunk/include/llvm/LTO/ThinLTOCodeGenerator.h Fri Apr 1 01:47:02 2016
> @@ -169,6 +169,13 @@ public:
> TMBuilder.CGOptLevel = CGOptLevel;
> }
>
> + /// Disable CodeGen, only run the stages till codegen and stop. The output
> + /// will be bitcode.
> + void disableCodeGen(bool Disable) { DisableCodeGen = Disable; }
> +
> + /// Perform CodeGen only: disable all other stages.
> + void setCodeGenOnly(bool CGOnly) { CodeGenOnly = CGOnly; }
> +
> /**@}*/
>
> /**
> @@ -228,6 +235,14 @@ private:
>
> /// Path to a directory to save the temporary bitcode files.
> std::string SaveTempsDir;
> +
> + /// Flag to enable/disable CodeGen. When set to true, the process stops after
> + /// optimizations and a bitcode is produced.
> + bool DisableCodeGen;
> +
> + /// Flag to indicate that only the CodeGen will be performed, no cross-module
> + /// importing or optimization.
> + bool CodeGenOnly;
> };
> }
> #endif
>
> Modified: llvm/trunk/lib/LTO/ThinLTOCodeGenerator.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/LTO/ThinLTOCodeGenerator.cpp?rev=265113&r1=265112&r2=265113&view=diff
> ==============================================================================
> --- llvm/trunk/lib/LTO/ThinLTOCodeGenerator.cpp (original)
> +++ llvm/trunk/lib/LTO/ThinLTOCodeGenerator.cpp Fri Apr 1 01:47:02 2016
> @@ -188,7 +188,8 @@ ProcessThinLTOModule(Module &TheModule,
> StringMap<MemoryBufferRef> &ModuleMap, TargetMachine &TM,
> const FunctionImporter::ImportMapTy &ImportList,
> ThinLTOCodeGenerator::CachingOptions CacheOptions,
> - StringRef SaveTempsDir, unsigned count) {
> + bool DisableCodeGen, StringRef SaveTempsDir,
> + unsigned count) {
>
> // Save temps: after IPO.
> saveTempBitcode(TheModule, SaveTempsDir, count, ".1.IPO.bc");
> @@ -212,6 +213,16 @@ ProcessThinLTOModule(Module &TheModule,
>
> saveTempBitcode(TheModule, SaveTempsDir, count, ".3.opt.bc");
>
> + if (DisableCodeGen) {
> + // Configured to stop before CodeGen, serialize the bitcode and return.
> + SmallVector<char, 128> OutputBuffer;
> + {
> + raw_svector_ostream OS(OutputBuffer);
> + WriteBitcodeToFile(&TheModule, OS, true, true);
> + }
> + return make_unique<ObjectMemoryBuffer>(std::move(OutputBuffer));
> + }
> +
> return codegenModule(TheModule, TM);
> }
>
> @@ -348,6 +359,28 @@ std::unique_ptr<MemoryBuffer> ThinLTOCod
>
> // Main entry point for the ThinLTO processing
> void ThinLTOCodeGenerator::run() {
> + if (CodeGenOnly) {
> + // Perform only parallel codegen and return.
> + ThreadPool Pool;
> + assert(ProducedBinaries.empty() && "The generator should not be reused");
> + ProducedBinaries.resize(Modules.size());
> + int count = 0;
> + for (auto &ModuleBuffer : Modules) {
> + Pool.async([&](int count) {
> + LLVMContext Context;
> + Context.setDiscardValueNames(LTODiscardValueNames);
> +
> + // Parse module now
> + auto TheModule = loadModuleFromBuffer(ModuleBuffer, Context, false);
> +
> + // CodeGen
> + ProducedBinaries[count] = codegen(*TheModule);
> + }, count++);
> + }
> +
> + return;
> + }
> +
> // Sequential linking phase
> auto Index = linkCombinedIndex();
>
> @@ -396,7 +429,7 @@ void ThinLTOCodeGenerator::run() {
> auto &ImportList = ImportLists[TheModule->getModuleIdentifier()];
> ProducedBinaries[count] = ProcessThinLTOModule(
> *TheModule, *Index, ModuleMap, *TMBuilder.create(), ImportList,
> - CacheOptions, SaveTempsDir, count);
> + CacheOptions, DisableCodeGen, SaveTempsDir, count);
> }, count);
> count++;
> }
>
> Modified: llvm/trunk/tools/lto/lto.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/lto/lto.cpp?rev=265113&r1=265112&r2=265113&view=diff
> ==============================================================================
> --- llvm/trunk/tools/lto/lto.cpp (original)
> +++ llvm/trunk/tools/lto/lto.cpp Fri Apr 1 01:47:02 2016
> @@ -473,6 +473,16 @@ LTOObjectBuffer thinlto_module_get_objec
> MemBuffer->getBufferSize()};
> }
>
> +void thinlto_codegen_disable_codegen(thinlto_code_gen_t cg,
> + lto_bool_t disable) {
> + unwrap(cg)->disableCodeGen(disable);
> +}
> +
> +void thinlto_codegen_set_codegen_only(thinlto_code_gen_t cg,
> + lto_bool_t CodeGenOnly) {
> + unwrap(cg)->setCodeGenOnly(CodeGenOnly);
> +}
> +
> void thinlto_debug_options(const char *const *options, int number) {
> // if options were requested, set them
> if (number && options) {
> @@ -483,7 +493,7 @@ void thinlto_debug_options(const char *c
> }
> }
>
> -bool lto_module_is_thinlto(lto_module_t mod) {
> +lto_bool_t lto_module_is_thinlto(lto_module_t mod) {
> return unwrap(mod)->isThinLTO();
> }
>
>
> Modified: llvm/trunk/tools/lto/lto.exports
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/lto/lto.exports?rev=265113&r1=265112&r2=265113&view=diff
> ==============================================================================
> --- llvm/trunk/tools/lto/lto.exports (original)
> +++ llvm/trunk/tools/lto/lto.exports Fri Apr 1 01:47:02 2016
> @@ -61,4 +61,6 @@ thinlto_debug_options
> lto_module_is_thinlto
> thinlto_codegen_add_must_preserve_symbol
> thinlto_codegen_add_cross_referenced_symbol
> -thinlto_codegen_set_final_cache_size_relative_to_available_space
> \ No newline at end of file
> +thinlto_codegen_set_final_cache_size_relative_to_available_space
> +thinlto_codegen_set_codegen_only
> +thinlto_codegen_disable_codegen
> \ No newline at end of file
>
>
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