[-gmodules] Honor -fdebug-prefix-map in the debug info inside PCMs.

This patch passes -fdebug-prefix-map (a feature for renaming source
paths in the debug info) through to the per-module codegen options and
adds the debug prefix map to the module hash.

<rdar://problem/46045865>

Differential Revision: https://reviews.llvm.org/D55037

llvm-svn: 347926

1 files changed, 6 insertions, 0 deletions

diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 8840e2e..f511fdc 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -3264,6 +3264,12 @@ std::string CompilerInvocation::getModuleHash() const {
     code = ext->hashExtension(code);
   }
 
+  // When compiling with -gmodules, also hash -fdebug-prefix-map as it
+  // affects the debug info in the PCM.
+  if (getCodeGenOpts().DebugTypeExtRefs)
+    for (const auto &KeyValue : getCodeGenOpts().DebugPrefixMap)
+      code = hash_combine(code, KeyValue.first, KeyValue.second);
+
   // Extend the signature with the enabled sanitizers, if at least one is
   // enabled. Sanitizers which cannot affect AST generation aren't hashed.
   SanitizerSet SanHash = LangOpts->Sanitize;