Merge pull request #5213 from akyrtzi/pr/stable/cmd-macro-and-pch

[stable][clang][cas] ScanAndUpdateArgs: Keep the preprocessor option macros for the include-tree

Author: akyrtzi

clang/lib/Tooling/DependencyScanning/ScanAndUpdateArgs.cpp

@@ -87,12 +87,19 @@ static void updateCompilerInvocation(CompilerInvocation &Invocation,
     Invocation.getFrontendOpts().Inputs.clear();
     Invocation.getHeaderSearchOpts() = HeaderSearchOptions();
     auto &PPOpts = Invocation.getPreprocessorOpts();
-    // We don't need these because we save the contents of the predefines buffer
-    // and the PCH file in the include tree root.
-    PPOpts.Macros.clear();
-    PPOpts.MacroIncludes.clear();
+    // We don't need this because we save the contents of the PCH file in the
+    // include tree root.
     PPOpts.ImplicitPCHInclude.clear();
-    PPOpts.Includes.clear();
+    if (Invocation.getFrontendOpts().ProgramAction != frontend::GeneratePCH) {
+      // We don't need these because we save the contents of the predefines
+      // buffer in the include tree. But if we generate a PCH file we still need
+      // to keep them as preprocessor options so that they are preserved in a
+      // PCH file and compared with the preprocessor options of the dep-scan
+      // invocation that uses the PCH.
+      PPOpts.Macros.clear();
+      PPOpts.MacroIncludes.clear();
+      PPOpts.Includes.clear();
+    }
   } else {
     FileSystemOpts.CASFileSystemRootID = RootID;
     FileSystemOpts.CASFileSystemWorkingDirectory = CASWorkingDirectory.str();
@@ -152,6 +159,12 @@ static void updateCompilerInvocation(CompilerInvocation &Invocation,
   remapInPlaceOrFilterOut(HeaderSearchOpts.PrebuiltModulePaths);
   remapInPlaceOrFilterOut(HeaderSearchOpts.VFSOverlayFiles);
 
+  // Preprocessor options.
+  auto &PPOpts = Invocation.getPreprocessorOpts();
+  remapInPlaceOrFilterOut(PPOpts.MacroIncludes);
+  remapInPlaceOrFilterOut(PPOpts.Includes);
+  Mapper.mapInPlaceOrClear(PPOpts.ImplicitPCHInclude);
+
   // Frontend options.
   remapInPlaceOrFilterOutWith(
       FrontendOpts.Inputs, [&](FrontendInputFile &Input) {

clang/test/CAS/cmd-macro-and-pch.c

@@ -0,0 +1,20 @@
+// RUN: rm -rf %t
+// RUN: split-file %s %t
+
+// Normal compilation for baseline.
+// RUN: %clang_cc1 -x c-header %t/prefix.h -DSOME_MACRO=1 -emit-pch -o %t/prefix1.pch -Werror
+// RUN: %clang_cc1 %t/t1.c -include-pch %t/prefix1.pch -DSOME_MACRO=1 -fsyntax-only -Werror
+
+// RUN: %clang -cc1depscan -o %t/pch.rsp -fdepscan=inline -fdepscan-include-tree -cc1-args \
+// RUN:     -cc1 -x c-header %t/prefix.h -emit-pch -DSOME_MACRO=1 -fcas-path %t/cas -Werror
+// RUN: %clang @%t/pch.rsp -emit-pch -o %t/prefix2.pch
+
+// RUN: %clang -cc1depscan -o %t/tu.rsp -fdepscan=inline -fdepscan-include-tree -cc1-args \
+// RUN:     -cc1 %t/t1.c -include-pch %t/prefix2.pch -DSOME_MACRO=1 -fcas-path %t/cas -Werror
+// RUN: %clang @%t/tu.rsp -fsyntax-only
+
+//--- t1.c
+
+//--- prefix.h
+#undef SOME_MACRO
+#define SOME_MACRO 0