[PATCH] D18009: [lto] Add saving the LTO .o file to -save-temps.

[Sean Silva via llvm-commits]

silvas created this revision.
silvas added reviewers: ruiu, rafael.
silvas added subscribers: llvm-commits, Bigcheese.
Herald added a subscriber: joker.eph.

This implements another part of -save-temps.
After this, the only remaining part is dumping the optimized bitcode. But
currently LLD's LTO doesn't have a non-intrusive place to put this.
Eventually we probably will and it will make sense to add it then.

After this patch, I have some NFC cleanups to make. I'll pull out a
`maybeSaveTemp(std::string Suffix, std::function<void(raw_ostream &)>)` and
simplify some of the names in the test.

http://reviews.llvm.org/D18009

Files:
  ELF/SymbolTable.cpp
  test/ELF/lto/save-temps.ll

Index: test/ELF/lto/save-temps.ll
===================================================================
--- test/ELF/lto/save-temps.ll
+++ test/ELF/lto/save-temps.ll
@@ -1,10 +1,11 @@
 ; REQUIRES: x86
-; RUN: rm -f %t.so %t.so.lto.bc
+; RUN: rm -f %t.so %t.so.lto.bc %t.so.lto.o
 ; RUN: llvm-as %s -o %t.o
 ; RUN: llvm-as %p/Inputs/save-temps.ll -o %t2.o
 ; RUN: ld.lld -shared -m elf_x86_64 %t.o %t2.o -o %t.so -save-temps
 ; RUN: llvm-nm %t.so | FileCheck %s
 ; RUN: llvm-nm %t.so.lto.bc | FileCheck %s
+; RUN: llvm-nm %t.so.lto.o | FileCheck %s
 
 target triple = "x86_64-unknown-linux-gnu"
 target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
Index: ELF/SymbolTable.cpp
===================================================================
--- ELF/SymbolTable.cpp
+++ ELF/SymbolTable.cpp
@@ -96,6 +96,15 @@
     resolve(B);
 }
 
+// This is for use when debugging LTO.
+static void saveLtoObjectFile(StringRef Buffer) {
+  std::error_code EC;
+  raw_fd_ostream OS(Config->OutputFile.str() + ".lto.o", EC,
+                    sys::fs::OpenFlags::F_None);
+  check(EC);
+  OS << Buffer;
+}
+
 // Codegen the module M and returns the resulting InputFile.
 template <class ELFT>
 std::unique_ptr<InputFile> SymbolTable<ELFT>::codegen(Module &M) {
@@ -123,6 +132,8 @@
     fatal("Failed to setup codegen");
   CodeGenPasses.run(M);
   LtoBuffer = MemoryBuffer::getMemBuffer(OwningLTOData, "", false);
+  if (Config->SaveTemps)
+    saveLtoObjectFile(LtoBuffer->getBuffer());
   return createObjectFile(*LtoBuffer);
 }
 


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