[ThinLTO] Print module summary index to assembly

Summary:
Implements AsmWriter support for printing the module summary index to
assembly with the format discussed in the RFC "LLVM Assembly format for
ThinLTO Summary".

Implements just enough of the parsing support to recognize and ignore
the summary entries. As agreed in the RFC thread, this will be the
behavior when assembling the IR. A follow on change will implement
parsing/assembling of the summary entries for use by tools that
currently build the summary index from bitcode.

Reviewers: dexonsmith, pcc

Subscribers: inglorion, eraman, steven_wu, dblaikie, llvm-commits

Differential Revision: https://reviews.llvm.org/D46699

llvm-svn: 333335

1 files changed, 17 insertions, 15 deletions

diff --git a/llvm/tools/llvm-dis/llvm-dis.cpp b/llvm/tools/llvm-dis/llvm-dis.cpp
index f254a761f87..8143a2a5a93 100644
--- a/llvm/tools/llvm-dis/llvm-dis.cpp
+++ b/llvm/tools/llvm-dis/llvm-dis.cpp
@@ -147,19 +147,6 @@ struct LLVMDisDiagnosticHandler : public DiagnosticHandler {
 
 static ExitOnError ExitOnErr;
 
-static std::unique_ptr<Module> openInputFile(LLVMContext &Context) {
-  std::unique_ptr<MemoryBuffer> MB =
-      ExitOnErr(errorOrToExpected(MemoryBuffer::getFileOrSTDIN(InputFilename)));
-  std::unique_ptr<Module> M = ExitOnErr(getOwningLazyBitcodeModule(
-      std::move(MB), Context,
-      /*ShouldLazyLoadMetadata=*/true, SetImporting));
-  if (MaterializeMetadata)
-    ExitOnErr(M->materializeMetadata());
-  else
-    ExitOnErr(M->materializeAll());
-  return M;
-}
-
 int main(int argc, char **argv) {
   InitLLVM X(argc, argv);
 
@@ -170,7 +157,19 @@ int main(int argc, char **argv) {
       llvm::make_unique<LLVMDisDiagnosticHandler>(argv[0]));
   cl::ParseCommandLineOptions(argc, argv, "llvm .bc -> .ll disassembler\n");
 
-  std::unique_ptr<Module> M = openInputFile(Context);
+  std::unique_ptr<MemoryBuffer> MB =
+      ExitOnErr(errorOrToExpected(MemoryBuffer::getFileOrSTDIN(InputFilename)));
+  std::unique_ptr<Module> M = ExitOnErr(getLazyBitcodeModule(
+      *MB, Context, /*ShouldLazyLoadMetadata=*/true, SetImporting));
+  if (MaterializeMetadata)
+    ExitOnErr(M->materializeMetadata());
+  else
+    ExitOnErr(M->materializeAll());
+
+  BitcodeLTOInfo LTOInfo = ExitOnErr(getBitcodeLTOInfo(*MB));
+  std::unique_ptr<ModuleSummaryIndex> Index;
+  if (LTOInfo.HasSummary)
+    Index = ExitOnErr(getModuleSummaryIndex(*MB));
 
   // Just use stdout.  We won't actually print anything on it.
   if (DontPrint)
@@ -199,8 +198,11 @@ int main(int argc, char **argv) {
     Annotator.reset(new CommentWriter());
 
   // All that llvm-dis does is write the assembly to a file.
-  if (!DontPrint)
+  if (!DontPrint) {
     M->print(Out->os(), Annotator.get(), PreserveAssemblyUseListOrder);
+    if (Index)
+      Index->print(Out->os());
+  }
 
   // Declare success.
   Out->keep();