Add an option to support debug fission on implicit ThinLTO.

Summary:
This adds an option -gsplit-dwarf=<arg>. LLVM can create .dwo files in the given directory
during the implicit ThinLTO link stage.

Reviewers: tejohnson, dblaikie, pcc

Reviewed By: pcc

Subscribers: steven_wu, aprantl, JDevlieghere, yunlian, probinson, mehdi_amini, inglorion, cfe-commits

Differential Revision: https://reviews.llvm.org/D44788

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@335546 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Driver/ToolChains/CommonArgs.cpp b/lib/Driver/ToolChains/CommonArgs.cpp
index 43f7d7f3b7b32ea3f637c4001d476111d8eea590..98a36bcd837e891c6d35a61f0c1bc5a6b0b27f4c 100644 (file)
--- a/lib/Driver/ToolChains/CommonArgs.cpp
+++ b/lib/Driver/ToolChains/CommonArgs.cpp
@@ -416,6 +416,12 @@ void tools::AddGoldPlugin(const ToolChain &ToolChain, const ArgList &Args,
       CmdArgs.push_back(Args.MakeArgString(Twine("-plugin-opt=O") + OOpt));
   }
 
+  if (Args.hasArg(options::OPT_gsplit_dwarf)) {
+    CmdArgs.push_back(
+        Args.MakeArgString(Twine("-plugin-opt=dwo_dir=") +
+            Output.getFilename() + "_dwo"));
+  }
+
   if (IsThinLTO)
     CmdArgs.push_back("-plugin-opt=thinlto");
 

diff --git a/test/Driver/lto-dwo.c b/test/Driver/lto-dwo.c
new file mode 100644 (file)
index 0000000..486ace4
--- /dev/null
+++ b/test/Driver/lto-dwo.c
@@ -0,0 +1,6 @@
+// Confirm that -gsplit-dwarf=DIR is passed to linker
+
+// RUN: %clang -target x86_64-unknown-linux -### %s -flto=thin -gsplit-dwarf -o a.out 2> %t
+// RUN: FileCheck -check-prefix=CHECK-LINK-DWO-DIR-DEFAULT < %t %s
+//
+// CHECK-LINK-DWO-DIR-DEFAULT: "-plugin-opt=dwo_dir=a.out_dwo"