[PATCH] D61742: [Driver][Windows] Add dependent lib argument for profile instr generate

[Russell Gallop via Phabricator via cfe-commits]

russell.gallop created this revision.
russell.gallop added reviewers: rnk, bogner.
russell.gallop added a project: clang.

This is needed so lld-link can find clang_rt.profile when self hosting on Windows with PGO.

Trying to self host on Windows with PGO runs into undefined symbols as lld-link doesn't know to link clang_rt.profile as discussed here:
http://lists.llvm.org/pipermail/llvm-dev/2019-January/129500.html

Using clang-cl as a linker knows to add the library but self hosting, using -DCMAKE_LINKER=<...>/lld-link.exe doesn't.  I think that the cleanest way to make this work is to add a dependent library when using profile-instr-generate on Windows.

Note some cmake changes are also required to get PGO self hosting on Windows working. I will post them separately.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D61742

Files:
  clang/lib/Driver/ToolChains/Clang.cpp
  clang/test/Driver/cl-options.c


Index: clang/test/Driver/cl-options.c
===================================================================
--- clang/test/Driver/cl-options.c
+++ clang/test/Driver/cl-options.c
@@ -66,7 +66,7 @@
 // RUN: %clang_cl -### /FA -fprofile-instr-generate=/tmp/somefile.profraw -- %s 2>&1 | FileCheck -check-prefix=CHECK-PROFILE-GENERATE-FILE %s
 // RUN: %clang_cl -### /FA -fprofile-instr-generate -fprofile-instr-use -- %s 2>&1 | FileCheck -check-prefix=CHECK-NO-MIX-GEN-USE %s
 // RUN: %clang_cl -### /FA -fprofile-instr-generate -fprofile-instr-use=file -- %s 2>&1 | FileCheck -check-prefix=CHECK-NO-MIX-GEN-USE %s
-// CHECK-PROFILE-GENERATE: "-fprofile-instrument=clang"
+// CHECK-PROFILE-GENERATE: "-fprofile-instrument=clang" "--dependent-lib={{[^"]*}}clang_rt.profile-{{[^"]*}}.lib"
 // CHECK-PROFILE-GENERATE-FILE: "-fprofile-instrument-path=/tmp/somefile.profraw"
 // CHECK-NO-MIX-GEN-USE: '{{[a-z=-]*}}' not allowed with '{{[a-z=-]*}}'
 
Index: clang/lib/Driver/ToolChains/Clang.cpp
===================================================================
--- clang/lib/Driver/ToolChains/Clang.cpp
+++ clang/lib/Driver/ToolChains/Clang.cpp
@@ -731,8 +731,9 @@
   Result.append(UID.begin(), UID.end());
 }
 
-static void addPGOAndCoverageFlags(Compilation &C, const Driver &D,
-                                   const InputInfo &Output, const ArgList &Args,
+static void addPGOAndCoverageFlags(const ToolChain &TC, Compilation &C,
+                                   const Driver &D, const InputInfo &Output,
+                                   const ArgList &Args,
                                    ArgStringList &CmdArgs) {
 
   auto *PGOGenerateArg = Args.getLastArg(options::OPT_fprofile_generate,
@@ -783,6 +784,11 @@
                                            ProfileGenerateArg->getValue()));
     // The default is to use Clang Instrumentation.
     CmdArgs.push_back("-fprofile-instrument=clang");
+    if (TC.getTriple().isOSWindows()) {
+      // Add dependent lib for clang_rt.profile
+      CmdArgs.push_back(Args.MakeArgString("--dependent-lib=" +
+                                           TC.getCompilerRT(Args, "profile")));
+    }
   }
 
   Arg *PGOGenArg = nullptr;
@@ -4176,7 +4182,7 @@
   // sampling, overhead of call arc collection is way too high and there's no
   // way to collect the output.
   if (!Triple.isNVPTX())
-    addPGOAndCoverageFlags(C, D, Output, Args, CmdArgs);
+    addPGOAndCoverageFlags(TC, C, D, Output, Args, CmdArgs);
 
   if (auto *ABICompatArg = Args.getLastArg(options::OPT_fclang_abi_compat_EQ))
     ABICompatArg->render(Args, CmdArgs);


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