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.
From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 265113
diff --git a/llvm/include/llvm-c/lto.h b/llvm/include/llvm-c/lto.h
index 42c2802..82f7fd7 100644
--- a/llvm/include/llvm-c/lto.h
+++ b/llvm/include/llvm-c/lto.h
@@ -44,7 +44,8 @@
* @{
*/
-#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_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
diff --git a/llvm/include/llvm/LTO/ThinLTOCodeGenerator.h b/llvm/include/llvm/LTO/ThinLTOCodeGenerator.h
index 76dad3d..3407c82 100644
--- a/llvm/include/llvm/LTO/ThinLTOCodeGenerator.h
+++ b/llvm/include/llvm/LTO/ThinLTOCodeGenerator.h
@@ -169,6 +169,13 @@
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 @@
/// 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
diff --git a/llvm/lib/LTO/ThinLTOCodeGenerator.cpp b/llvm/lib/LTO/ThinLTOCodeGenerator.cpp
index c80e7bd..412475d 100644
--- a/llvm/lib/LTO/ThinLTOCodeGenerator.cpp
+++ b/llvm/lib/LTO/ThinLTOCodeGenerator.cpp
@@ -188,7 +188,8 @@
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 @@
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 @@
// 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 @@
auto &ImportList = ImportLists[TheModule->getModuleIdentifier()];
ProducedBinaries[count] = ProcessThinLTOModule(
*TheModule, *Index, ModuleMap, *TMBuilder.create(), ImportList,
- CacheOptions, SaveTempsDir, count);
+ CacheOptions, DisableCodeGen, SaveTempsDir, count);
}, count);
count++;
}
diff --git a/llvm/tools/lto/lto.cpp b/llvm/tools/lto/lto.cpp
index 165b23d..e22b198 100644
--- a/llvm/tools/lto/lto.cpp
+++ b/llvm/tools/lto/lto.cpp
@@ -473,6 +473,16 @@
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 @@
}
}
-bool lto_module_is_thinlto(lto_module_t mod) {
+lto_bool_t lto_module_is_thinlto(lto_module_t mod) {
return unwrap(mod)->isThinLTO();
}
diff --git a/llvm/tools/lto/lto.exports b/llvm/tools/lto/lto.exports
index e0df0ca..83a5943 100644
--- a/llvm/tools/lto/lto.exports
+++ b/llvm/tools/lto/lto.exports
@@ -61,4 +61,6 @@
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