[opt][clang] Enable using -module-summary/-flto=thin with -S/-emit-llvm

Enable using -module-summary with -S
(similarly to what currently can be achieved with opt <input> -o - | llvm-dis).
This is a recommit of ef9e624.

Test plan: ninja check-all

Differential revision: https://reviews.llvm.org/D137768

clang/lib/CodeGen/BackendUtil.cpp

@@ -983,19 +983,24 @@ void EmitAssemblyHelper::RunOptimizationPipeline(
   if (!actionRequiresCodeGen(Action) && CodeGenOpts.VerifyModule)
     MPM.addPass(VerifierPass());
 
-  switch (Action) {
-  case Backend_EmitBC:
+  if (Action == Backend_EmitBC || Action == Backend_EmitLL) {
     if (CodeGenOpts.PrepareForThinLTO && !CodeGenOpts.DisableLLVMPasses) {
-      if (!CodeGenOpts.ThinLinkBitcodeFile.empty()) {
-        ThinLinkOS = openOutputFile(CodeGenOpts.ThinLinkBitcodeFile);
-        if (!ThinLinkOS)
-          return;
-      }
       if (!TheModule->getModuleFlag("EnableSplitLTOUnit"))
         TheModule->addModuleFlag(Module::Error, "EnableSplitLTOUnit",
                                  CodeGenOpts.EnableSplitLTOUnit);
-      MPM.addPass(ThinLTOBitcodeWriterPass(*OS, ThinLinkOS ? &ThinLinkOS->os()
-                                                           : nullptr));
+      if (Action == Backend_EmitBC) {
+        if (!CodeGenOpts.ThinLinkBitcodeFile.empty()) {
+          ThinLinkOS = openOutputFile(CodeGenOpts.ThinLinkBitcodeFile);
+          if (!ThinLinkOS)
+            return;
+        }
+        MPM.addPass(ThinLTOBitcodeWriterPass(*OS, ThinLinkOS ? &ThinLinkOS->os()
+                                                             : nullptr));
+      } else {
+        MPM.addPass(PrintModulePass(*OS, "", CodeGenOpts.EmitLLVMUseLists,
+                                    /*EmitLTOSummary=*/true));
+      }
+
     } else {
       // Emit a module summary by default for Regular LTO except for ld64
       // targets
@@ -1007,17 +1012,13 @@ void EmitAssemblyHelper::RunOptimizationPipeline(
           TheModule->addModuleFlag(Module::Error, "EnableSplitLTOUnit",
                                    uint32_t(1));
       }
-      MPM.addPass(
-          BitcodeWriterPass(*OS, CodeGenOpts.EmitLLVMUseLists, EmitLTOSummary));
+      if (Action == Backend_EmitBC)
+        MPM.addPass(BitcodeWriterPass(*OS, CodeGenOpts.EmitLLVMUseLists,
+                                      EmitLTOSummary));
+      else
+        MPM.addPass(PrintModulePass(*OS, "", CodeGenOpts.EmitLLVMUseLists,
+                                    EmitLTOSummary));
     }
-    break;
-
-  case Backend_EmitLL:
-    MPM.addPass(PrintModulePass(*OS, "", CodeGenOpts.EmitLLVMUseLists));
-    break;
-
-  default:
-    break;
   }
 
   // Now that we have all of the passes ready, run them.

clang/test/CodeGen/split-lto-unit.c

@@ -1,12 +1,15 @@
 // ; Check that -flto=thin without -fsplit-lto-unit has EnableSplitLTOUnit = 0
 // RUN: %clang_cc1 -flto=thin -emit-llvm-bc < %s | llvm-dis -o - | FileCheck %s
+// RUN: %clang_cc1 -flto=thin -emit-llvm < %s | FileCheck %s
 // CHECK: !{i32 1, !"EnableSplitLTOUnit", i32 0}
 //
 // ; Check that -flto=thin with -fsplit-lto-unit has EnableSplitLTOUnit = 1
 // RUN: %clang_cc1 -flto=thin -fsplit-lto-unit -emit-llvm-bc < %s | llvm-dis -o - | FileCheck %s --check-prefix=SPLIT
+// RUN: %clang_cc1 -flto=thin -fsplit-lto-unit -emit-llvm < %s | FileCheck %s --check-prefix=SPLIT
 // SPLIT: !{i32 1, !"EnableSplitLTOUnit", i32 1}
 //
 // ; Check that regular LTO has EnableSplitLTOUnit = 1
 // RUN: %clang_cc1 -flto -triple x86_64-pc-linux-gnu -emit-llvm-bc < %s | llvm-dis -o - | FileCheck %s --implicit-check-not="EnableSplitLTOUnit" --check-prefix=SPLIT
+// RUN: %clang_cc1 -flto -triple x86_64-pc-linux-gnu -emit-llvm < %s | FileCheck %s --implicit-check-not="EnableSplitLTOUnit" --check-prefix=SPLIT
 
 int main(void) {}

llvm/include/llvm/IRPrinter/IRPrintingPasses.h

@@ -34,11 +34,13 @@ class PrintModulePass : public PassInfoMixin<PrintModulePass> {
   raw_ostream &OS;
   std::string Banner;
   bool ShouldPreserveUseListOrder;
+  bool EmitSummaryIndex;
 
 public:
   PrintModulePass();
   PrintModulePass(raw_ostream &OS, const std::string &Banner = "",
-                  bool ShouldPreserveUseListOrder = false);
+                  bool ShouldPreserveUseListOrder = false,
+                  bool EmitSummaryIndex = false);
 
   PreservedAnalyses run(Module &M, AnalysisManager<Module> &);
   static bool isRequired() { return true; }

llvm/lib/IRPrinter/CMakeLists.txt

@@ -8,6 +8,7 @@ add_llvm_component_library(LLVMIRPrinter
   intrinsics_gen
 
   LINK_COMPONENTS
+  Analysis
   Core
   Support
   )

llvm/lib/IRPrinter/IRPrintingPasses.cpp

@@ -12,6 +12,7 @@
 
 #include "llvm/IRPrinter/IRPrintingPasses.h"
 #include "llvm/ADT/StringRef.h"
+#include "llvm/Analysis/ModuleSummaryAnalysis.h"
 #include "llvm/IR/Function.h"
 #include "llvm/IR/Module.h"
 #include "llvm/IR/PrintPasses.h"
@@ -23,11 +24,13 @@ using namespace llvm;
 
 PrintModulePass::PrintModulePass() : OS(dbgs()) {}
 PrintModulePass::PrintModulePass(raw_ostream &OS, const std::string &Banner,
-                                 bool ShouldPreserveUseListOrder)
+                                 bool ShouldPreserveUseListOrder,
+                                 bool EmitSummaryIndex)
     : OS(OS), Banner(Banner),
-      ShouldPreserveUseListOrder(ShouldPreserveUseListOrder) {}
+      ShouldPreserveUseListOrder(ShouldPreserveUseListOrder),
+      EmitSummaryIndex(EmitSummaryIndex) {}
 
-PreservedAnalyses PrintModulePass::run(Module &M, ModuleAnalysisManager &) {
+PreservedAnalyses PrintModulePass::run(Module &M, ModuleAnalysisManager &AM) {
   if (llvm::isFunctionInPrintList("*")) {
     if (!Banner.empty())
       OS << Banner << "\n";
@@ -44,6 +47,16 @@ PreservedAnalyses PrintModulePass::run(Module &M, ModuleAnalysisManager &) {
       }
     }
   }
+
+  ModuleSummaryIndex *Index =
+      EmitSummaryIndex ? &(AM.getResult<ModuleSummaryIndexAnalysis>(M))
+                       : nullptr;
+  if (Index) {
+    if (Index->modulePaths().empty())
+      Index->addModule("", 0);
+    Index->print(OS);
+  }
+
   return PreservedAnalyses::all();
 }
 

llvm/test/Bitcode/thinlto-function-summary.ll

@@ -31,6 +31,8 @@
 
 
 ; RUN: opt -passes=name-anon-globals -module-summary < %s | llvm-dis | FileCheck %s
+; RUN: opt -passes=name-anon-globals -module-summary -S < %s | FileCheck %s
+; RUN: opt -passes=name-anon-globals -module-summary -S < %s | llvm-as | llvm-dis | FileCheck %s
 ; Check that this round-trips correctly.
 
 ; ModuleID = '<stdin>'

llvm/tools/opt/NewPMDriver.cpp

@@ -443,16 +443,16 @@ bool llvm::runPassPipeline(StringRef Arg0, Module &M, TargetMachine *TM,
     MPM.addPass(NewPMCheckDebugifyPass(false, "", &DIStatsMap));
   if (VerifyDIPreserve)
     MPM.addPass(NewPMCheckDebugifyPass(
-        false, "", nullptr, DebugifyMode::OriginalDebugInfo, &DebugInfoBeforePass,
-        VerifyDIPreserveExport));
+        false, "", nullptr, DebugifyMode::OriginalDebugInfo,
+        &DebugInfoBeforePass, VerifyDIPreserveExport));
 
   // Add any relevant output pass at the end of the pipeline.
   switch (OK) {
   case OK_NoOutput:
     break; // No output pass needed.
   case OK_OutputAssembly:
-    MPM.addPass(
-        PrintModulePass(Out->os(), "", ShouldPreserveAssemblyUseListOrder));
+    MPM.addPass(PrintModulePass(
+        Out->os(), "", ShouldPreserveAssemblyUseListOrder, EmitSummaryIndex));
     break;
   case OK_OutputBitcode:
     MPM.addPass(BitcodeWriterPass(Out->os(), ShouldPreserveBitcodeUseListOrder,

utils/bazel/llvm-project-overlay/llvm/BUILD.bazel

@@ -1386,6 +1386,7 @@ cc_library(
     ]),
     copts = llvm_copts,
     deps = [
+        ":Analysis",
         ":Core",
         ":Support",
     ],