[clang][modules] Reset codegen options. (#74006)

CodeGen options do not affect the AST, so they usually can be ignored.
The only exception to the rule is when a PCM is created with
`-gmodules`.
In that case the Clang module format is switched to object file
container and contains also serialized debug information that can be
affected by debug options. There the following approach was choosen:

1.) Split out all the debug options into a separate `DebugOptions.def`
    file. The file is included by `CodeGenOptions.def`, so the change is
    transparent to all existing users of `CodeGenOptions.def`.
2.) Reset all CodeGen options, but excluding affecting debug options.
3.) Conditionally reset debug options that can affect the PCM.

This fixes rdar://113135909.

2 files changed, 48 insertions, 0 deletions

diff --git a/clang/lib/Basic/CodeGenOptions.cpp b/clang/lib/Basic/CodeGenOptions.cpp
index 0c609cf..1b9f67c 100644
--- a/clang/lib/Basic/CodeGenOptions.cpp
+++ b/clang/lib/Basic/CodeGenOptions.cpp
@@ -20,4 +20,39 @@ CodeGenOptions::CodeGenOptions() {
   memcpy(CoverageVersion, "408*", 4);
 }
 
+void CodeGenOptions::resetNonModularOptions(StringRef ModuleFormat) {
+  // First reset all CodeGen options only. The Debug options are handled later.
+#define DEBUGOPT(Name, Bits, Default)
+#define VALUE_DEBUGOPT(Name, Bits, Default)
+#define ENUM_DEBUGOPT(Name, Type, Bits, Default)
+#define CODEGENOPT(Name, Bits, Default) Name = Default;
+#define ENUM_CODEGENOPT(Name, Type, Bits, Default) set##Name(Default);
+#include "clang/Basic/CodeGenOptions.def"
+
+  // Next reset all debug options that can always be reset, because they never
+  // affect the PCM.
+#define DEBUGOPT(Name, Bits, Default)
+#define VALUE_DEBUGOPT(Name, Bits, Default)
+#define ENUM_DEBUGOPT(Name, Type, Bits, Default)
+#define BENIGN_DEBUGOPT(Name, Bits, Default) Name = Default;
+#define BENIGN_VALUE_DEBUGOPT(Name, Bits, Default) Name = Default;
+#define BENIGN_ENUM_DEBUGOPT(Name, Type, Bits, Default) set##Name(Default);
+#include "clang/Basic/DebugOptions.def"
+
+  // Conditionally reset debug options that only matter when the debug info is
+  // emitted into the PCM (-gmodules).
+  if (ModuleFormat == "raw") {
+#define DEBUGOPT(Name, Bits, Default) Name = Default;
+#define VALUE_DEBUGOPT(Name, Bits, Default) Name = Default;
+#define ENUM_DEBUGOPT(Name, Type, Bits, Default) set##Name(Default);
+#define BENIGN_DEBUGOPT(Name, Bits, Default)
+#define BENIGN_VALUE_DEBUGOPT(Name, Bits, Default)
+#define BENIGN_ENUM_DEBUGOPT(Name, Type, Bits, Default)
+#include "clang/Basic/DebugOptions.def"
+  }
+
+  RelocationModel = llvm::Reloc::PIC_;
+  memcpy(CoverageVersion, "408*", 4);
+}
+
 }  // end namespace clang
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index be0d496..56de0f7 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -4787,6 +4787,18 @@ std::string CompilerInvocation::getModuleHash() const {
   if (getCodeGenOpts().DebugTypeExtRefs)
     HBuilder.addRange(getCodeGenOpts().DebugPrefixMap);
 
+  // Extend the signature with the affecting debug options.
+  if (getHeaderSearchOpts().ModuleFormat == "obj") {
+#define DEBUGOPT(Name, Bits, Default) HBuilder.add(CodeGenOpts->Name);
+#define VALUE_DEBUGOPT(Name, Bits, Default) HBuilder.add(CodeGenOpts->Name);
+#define ENUM_DEBUGOPT(Name, Type, Bits, Default)                               \
+  HBuilder.add(static_cast<unsigned>(CodeGenOpts->get##Name()));
+#define BENIGN_DEBUGOPT(Name, Bits, Default)
+#define BENIGN_VALUE_DEBUGOPT(Name, Bits, Default)
+#define BENIGN_ENUM_DEBUGOPT(Name, Type, Bits, Default)
+#include "clang/Basic/DebugOptions.def"
+  }
+
   // Extend the signature with the enabled sanitizers, if at least one is
   // enabled. Sanitizers which cannot affect AST generation aren't hashed.
   SanitizerSet SanHash = getLangOpts().Sanitize;
@@ -4833,6 +4845,7 @@ std::vector<std::string> CompilerInvocationBase::getCC1CommandLine() const {
 void CompilerInvocation::resetNonModularOptions() {
   getLangOpts().resetNonModularOptions();
   getPreprocessorOpts().resetNonModularOptions();
+  getCodeGenOpts().resetNonModularOptions(getHeaderSearchOpts().ModuleFormat);
 }
 
 void CompilerInvocation::clearImplicitModuleBuildOptions() {