tobiasvk updated this revision to Diff 102585.
tobiasvk added a comment.
- Change patch to always emit a module summary for regular LTO
I don't see any real downside of having a summary given the marginal time and
space overhead it takes to construct and save it.
https://reviews.llvm.org/D34156
Files:
clang/include/clang/Frontend/CodeGenOptions.def
clang/lib/CodeGen/BackendUtil.cpp
clang/lib/Frontend/CompilerInvocation.cpp
clang/test/CodeGen/emit-summary-index.c
clang/test/Misc/thinlto.c
Index: clang/test/Misc/thinlto.c
===================================================================
--- clang/test/Misc/thinlto.c
+++ /dev/null
@@ -1,4 +0,0 @@
-// RUN: %clang_cc1 -flto=thin -emit-llvm-bc < %s | llvm-bcanalyzer -dump | FileCheck %s
-// ; Check that the -flto=thin option emits a summary
-// CHECK: <GLOBALVAL_SUMMARY_BLOCK
-int main() {}
Index: clang/test/CodeGen/emit-summary-index.c
===================================================================
--- /dev/null
+++ clang/test/CodeGen/emit-summary-index.c
@@ -0,0 +1,12 @@
+// RUN: %clang_cc1 -flto=thin -emit-llvm-bc < %s | llvm-bcanalyzer -dump | FileCheck %s
+// ; Check that the -flto=thin option emits a ThinLTO summary
+// CHECK: <GLOBALVAL_SUMMARY_BLOCK
+//
+// RUN: %clang_cc1 -flto -triple x86_64-apple-darwin -emit-llvm-bc < %s | llvm-bcanalyzer -dump | FileCheck --check-prefix=LTO %s
+// ; Check that we do not emit a summary for regular LTO on Apple platforms
+// LTO-NOT: GLOBALVAL_SUMMARY_BLOCK
+//
+// RUN: %clang_cc1 -flto -triple x86_64-pc-linux-gnu -emit-llvm-bc < %s | llvm-bcanalyzer -dump | FileCheck --check-prefix=LTOINDEX %s
+// ; Check that we emit a summary for regular LTO by default elsewhere
+// LTOINDEX: <FULL_LTO_GLOBALVAL_SUMMARY_BLOCK
+int main() {}
Index: clang/lib/Frontend/CompilerInvocation.cpp
===================================================================
--- clang/lib/Frontend/CompilerInvocation.cpp
+++ clang/lib/Frontend/CompilerInvocation.cpp
@@ -649,11 +649,11 @@
Opts.NoUseJumpTables = Args.hasArg(OPT_fno_jump_tables);
Opts.PrepareForLTO = Args.hasArg(OPT_flto, OPT_flto_EQ);
- Opts.EmitSummaryIndex = false;
+ Opts.PrepareForThinLTO = false;
if (Arg *A = Args.getLastArg(OPT_flto_EQ)) {
StringRef S = A->getValue();
if (S == "thin")
- Opts.EmitSummaryIndex = true;
+ Opts.PrepareForThinLTO = true;
else if (S != "full")
Diags.Report(diag::err_drv_invalid_value) << A->getAsString(Args) << S;
}
Index: clang/lib/CodeGen/BackendUtil.cpp
===================================================================
--- clang/lib/CodeGen/BackendUtil.cpp
+++ clang/lib/CodeGen/BackendUtil.cpp
@@ -486,7 +486,7 @@
PMBuilder.Inliner = createFunctionInliningPass(
CodeGenOpts.OptimizationLevel, CodeGenOpts.OptimizeSize,
(!CodeGenOpts.SampleProfileFile.empty() &&
- CodeGenOpts.EmitSummaryIndex));
+ CodeGenOpts.PrepareForThinLTO));
}
PMBuilder.OptLevel = CodeGenOpts.OptimizationLevel;
@@ -497,7 +497,7 @@
PMBuilder.DisableUnrollLoops = !CodeGenOpts.UnrollLoops;
PMBuilder.MergeFunctions = CodeGenOpts.MergeFunctions;
- PMBuilder.PrepareForThinLTO = CodeGenOpts.EmitSummaryIndex;
+ PMBuilder.PrepareForThinLTO = CodeGenOpts.PrepareForThinLTO;
PMBuilder.PrepareForLTO = CodeGenOpts.PrepareForLTO;
PMBuilder.RerollLoops = CodeGenOpts.RerollLoops;
@@ -733,12 +733,20 @@
std::unique_ptr<raw_fd_ostream> ThinLinkOS;
+ // Emit a module summary by default for Regular LTO except for ld64 targets
+ bool EmitLTOSummary =
+ (CodeGenOpts.PrepareForLTO && !CodeGenOpts.PrepareForThinLTO &&
+ llvm::Triple(TheModule->getTargetTriple()).getVendor() !=
+ llvm::Triple::Apple);
+ if (EmitLTOSummary)
+ TheModule->addModuleFlag(Module::Error, "ThinLTO", uint32_t(0));
+
switch (Action) {
case Backend_EmitNothing:
break;
case Backend_EmitBC:
- if (CodeGenOpts.EmitSummaryIndex) {
+ if (CodeGenOpts.PrepareForThinLTO) {
if (!CodeGenOpts.ThinLinkBitcodeFile.empty()) {
std::error_code EC;
ThinLinkOS.reset(new llvm::raw_fd_ostream(
@@ -755,7 +763,8 @@
}
else
PerModulePasses.add(
- createBitcodeWriterPass(*OS, CodeGenOpts.EmitLLVMUseLists));
+ createBitcodeWriterPass(*OS, CodeGenOpts.EmitLLVMUseLists,
+ EmitLTOSummary));
break;
case Backend_EmitLL:
@@ -895,6 +904,14 @@
}
}
+ // Emit a module summary by default for Regular LTO except for ld64 targets
+ bool EmitLTOSummary =
+ (CodeGenOpts.PrepareForLTO && !CodeGenOpts.PrepareForThinLTO &&
+ llvm::Triple(TheModule->getTargetTriple()).getVendor() !=
+ llvm::Triple::Apple);
+ if (EmitLTOSummary)
+ TheModule->addModuleFlag(Module::Error, "ThinLTO", uint32_t(0));
+
// FIXME: We still use the legacy pass manager to do code generation. We
// create that pass manager here and use it as needed below.
legacy::PassManager CodeGenPasses;
@@ -907,7 +924,7 @@
break;
case Backend_EmitBC:
- if (CodeGenOpts.EmitSummaryIndex) {
+ if (CodeGenOpts.PrepareForThinLTO) {
if (!CodeGenOpts.ThinLinkBitcodeFile.empty()) {
std::error_code EC;
ThinLinkOS.emplace(CodeGenOpts.ThinLinkBitcodeFile, EC,
@@ -922,8 +939,7 @@
ThinLTOBitcodeWriterPass(*OS, ThinLinkOS ? &*ThinLinkOS : nullptr));
} else {
MPM.addPass(BitcodeWriterPass(*OS, CodeGenOpts.EmitLLVMUseLists,
- CodeGenOpts.EmitSummaryIndex,
- CodeGenOpts.EmitSummaryIndex));
+ EmitLTOSummary));
}
break;
Index: clang/include/clang/Frontend/CodeGenOptions.def
===================================================================
--- clang/include/clang/Frontend/CodeGenOptions.def
+++ clang/include/clang/Frontend/CodeGenOptions.def
@@ -88,7 +88,7 @@
///< be generated.
CODEGENOPT(PrepareForLTO , 1, 0) ///< Set when -flto is enabled on the
///< compile step.
-CODEGENOPT(EmitSummaryIndex, 1, 0) ///< Set when -flto=thin is enabled on the
+CODEGENOPT(PrepareForThinLTO , 1, 0) ///< Set when -flto=thin is enabled on the
///< compile step.
CODEGENOPT(LTOUnit, 1, 0) ///< Emit IR to support LTO unit features (CFI, whole
///< program vtable opt).
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