Revert "[LTO] Enable module summary emission by default for regular LTO"

This is breaking a couple of buildbots. We need to run the
NameAnonGlobal pass for regular LTO now as well (since we're producing a
summary). I'll post a separate patch for review to make this happen and
then re-commit.

This reverts commit c0759b7b1f4a81ff9021b952aa38a222d5fa4dfd.

llvm-svn: 335291

clang/include/clang/Frontend/CodeGenOptions.def

@@ -110,7 +110,7 @@ CODEGENOPT(LessPreciseFPMAD  , 1, 0) ///< Enable less precise MAD instructions t
                                      ///< be generated.
 CODEGENOPT(PrepareForLTO     , 1, 0) ///< Set when -flto is enabled on the
                                      ///< compile step.
-CODEGENOPT(PrepareForThinLTO , 1, 0) ///< Set when -flto=thin is enabled on the
+CODEGENOPT(EmitSummaryIndex, 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).

clang/lib/CodeGen/BackendUtil.cpp

@@ -524,7 +524,7 @@ void EmitAssemblyHelper::CreatePasses(legacy::PassManager &MPM,
     PMBuilder.Inliner = createFunctionInliningPass(
         CodeGenOpts.OptimizationLevel, CodeGenOpts.OptimizeSize,
         (!CodeGenOpts.SampleProfileFile.empty() &&
-         CodeGenOpts.PrepareForThinLTO));
+         CodeGenOpts.EmitSummaryIndex));
   }
 
   PMBuilder.OptLevel = CodeGenOpts.OptimizationLevel;
@@ -534,7 +534,7 @@ void EmitAssemblyHelper::CreatePasses(legacy::PassManager &MPM,
 
   PMBuilder.DisableUnrollLoops = !CodeGenOpts.UnrollLoops;
   PMBuilder.MergeFunctions = CodeGenOpts.MergeFunctions;
-  PMBuilder.PrepareForThinLTO = CodeGenOpts.PrepareForThinLTO;
+  PMBuilder.PrepareForThinLTO = CodeGenOpts.EmitSummaryIndex;
   PMBuilder.PrepareForLTO = CodeGenOpts.PrepareForLTO;
   PMBuilder.RerollLoops = CodeGenOpts.RerollLoops;
 
@@ -776,7 +776,7 @@ void EmitAssemblyHelper::EmitAssembly(BackendAction Action,
     break;
 
   case Backend_EmitBC:
-    if (CodeGenOpts.PrepareForThinLTO) {
+    if (CodeGenOpts.EmitSummaryIndex) {
       if (!CodeGenOpts.ThinLinkBitcodeFile.empty()) {
         ThinLinkOS = openOutputFile(CodeGenOpts.ThinLinkBitcodeFile);
         if (!ThinLinkOS)
@@ -784,20 +784,10 @@ void EmitAssemblyHelper::EmitAssembly(BackendAction Action,
       }
       PerModulePasses.add(createWriteThinLTOBitcodePass(
           *OS, ThinLinkOS ? &ThinLinkOS->os() : nullptr));
-    } else {
-      // Emit a module summary by default for Regular LTO except for ld64
-      // targets
-      bool EmitLTOSummary =
-          (CodeGenOpts.PrepareForLTO &&
-           llvm::Triple(TheModule->getTargetTriple()).getVendor() !=
-               llvm::Triple::Apple);
-      if (EmitLTOSummary && !TheModule->getModuleFlag("ThinLTO"))
-        TheModule->addModuleFlag(Module::Error, "ThinLTO", uint32_t(0));
-
-      PerModulePasses.add(
-          createBitcodeWriterPass(*OS, CodeGenOpts.EmitLLVMUseLists,
-                                  EmitLTOSummary));
     }
+    else
+      PerModulePasses.add(
+          createBitcodeWriterPass(*OS, CodeGenOpts.EmitLLVMUseLists));
     break;
 
   case Backend_EmitLL:
@@ -945,7 +935,7 @@ void EmitAssemblyHelper::EmitAssemblyWithNewPassManager(
   ModulePassManager MPM(CodeGenOpts.DebugPassManager);
 
   if (!CodeGenOpts.DisableLLVMPasses) {
-    bool IsThinLTO = CodeGenOpts.PrepareForThinLTO;
+    bool IsThinLTO = CodeGenOpts.EmitSummaryIndex;
     bool IsLTO = CodeGenOpts.PrepareForLTO;
 
     if (CodeGenOpts.OptimizationLevel == 0) {
@@ -1006,7 +996,7 @@ void EmitAssemblyHelper::EmitAssemblyWithNewPassManager(
     break;
 
   case Backend_EmitBC:
-    if (CodeGenOpts.PrepareForThinLTO) {
+    if (CodeGenOpts.EmitSummaryIndex) {
       if (!CodeGenOpts.ThinLinkBitcodeFile.empty()) {
         ThinLinkOS = openOutputFile(CodeGenOpts.ThinLinkBitcodeFile);
         if (!ThinLinkOS)
@@ -1015,17 +1005,9 @@ void EmitAssemblyHelper::EmitAssemblyWithNewPassManager(
       MPM.addPass(ThinLTOBitcodeWriterPass(*OS, ThinLinkOS ? &ThinLinkOS->os()
                                                            : nullptr));
     } else {
-      // Emit a module summary by default for Regular LTO except for ld64
-      // targets
-      bool EmitLTOSummary =
-          (CodeGenOpts.PrepareForLTO &&
-           llvm::Triple(TheModule->getTargetTriple()).getVendor() !=
-               llvm::Triple::Apple);
-      if (EmitLTOSummary && !TheModule->getModuleFlag("ThinLTO"))
-        TheModule->addModuleFlag(Module::Error, "ThinLTO", uint32_t(0));
-
       MPM.addPass(BitcodeWriterPass(*OS, CodeGenOpts.EmitLLVMUseLists,
-                                    EmitLTOSummary));
+                                    CodeGenOpts.EmitSummaryIndex,
+                                    CodeGenOpts.EmitSummaryIndex));
     }
     break;
 

clang/lib/CodeGen/CGDebugInfo.cpp

@@ -578,7 +578,7 @@ void CGDebugInfo::CreateCompileUnit() {
                           CSInfo,
                           getSource(SM, SM.getMainFileID())),
       CGOpts.EmitVersionIdentMetadata ? Producer : "",
-      LO.Optimize || CGOpts.PrepareForLTO || CGOpts.PrepareForThinLTO,
+      LO.Optimize || CGOpts.PrepareForLTO || CGOpts.EmitSummaryIndex,
       CGOpts.DwarfDebugFlags, RuntimeVers,
       CGOpts.EnableSplitDwarf ? "" : CGOpts.SplitDwarfFile, EmissionKind,
       0 /* DWOid */, CGOpts.SplitDwarfInlining, CGOpts.DebugInfoForProfiling,

clang/lib/Frontend/CompilerInvocation.cpp

@@ -749,11 +749,11 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
   Opts.ProfileSampleAccurate = Args.hasArg(OPT_fprofile_sample_accurate);
 
   Opts.PrepareForLTO = Args.hasArg(OPT_flto, OPT_flto_EQ);
-  Opts.PrepareForThinLTO = false;
+  Opts.EmitSummaryIndex = false;
   if (Arg *A = Args.getLastArg(OPT_flto_EQ)) {
     StringRef S = A->getValue();
     if (S == "thin")
-      Opts.PrepareForThinLTO = true;
+      Opts.EmitSummaryIndex = true;
     else if (S != "full")
       Diags.Report(diag::err_drv_invalid_value) << A->getAsString(Args) << S;
   }

clang/test/CodeGen/emit-summary-index.c

@@ -1,17 +0,0 @@
-// ; Check that the -flto=thin option emits a ThinLTO summary
-// RUN: %clang_cc1 -flto=thin -emit-llvm-bc < %s | llvm-bcanalyzer -dump | FileCheck %s
-// CHECK: <GLOBALVAL_SUMMARY_BLOCK
-//
-// ; Check that we do not emit a summary for regular LTO on Apple platforms
-// RUN: %clang_cc1 -flto -triple x86_64-apple-darwin -emit-llvm-bc < %s | llvm-bcanalyzer -dump | FileCheck --check-prefix=LTO %s
-// LTO-NOT: GLOBALVAL_SUMMARY_BLOCK
-//
-// ; Check that we emit a summary for regular LTO by default elsewhere
-// RUN: %clang_cc1 -flto -triple x86_64-pc-linux-gnu -emit-llvm-bc < %s | llvm-bcanalyzer -dump | FileCheck --check-prefix=LTOINDEX %s
-// LTOINDEX: <FULL_LTO_GLOBALVAL_SUMMARY_BLOCK
-//
-// ; Simulate -save-temps and check that it works (!"ThinLTO" module flag not added multiple times)
-// RUN: %clang_cc1 -flto -triple x86_64-pc-linux-gnu -emit-llvm-bc -disable-llvm-passes < %s -o %t.bc
-// RUN: %clang_cc1 -flto -triple x86_64-pc-linux-gnu -emit-llvm-bc -x ir < %t.bc | llvm-bcanalyzer -dump | FileCheck --check-prefix=LTOINDEX %s
-
-int main() {}

clang/test/Misc/thinlto.c

@@ -0,0 +1,4 @@
+// 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() {}