[clang] don't serialize MODULE_DIRECTORY with ModuleFileHomeIsCwd

[rmaz]

Summary

Fix a bug in the MODULE_DIRECTORY serialization logic
that would cause MODULE_DIRECTORY to be serialized when
-fmodule-file-home-is-cwd is specified.

This matches the original logic added in:
https://github.com/apple/llvm-project/commit/f7b41371d9ede1aecf0930e5bd4a463519264633

[keith]

clang/test/Modules/module-file-home-is-cwd.m

7–9

Instead of doing 2 invocations you can do --check-prefixes=CHECK,INPUT

clang/lib/Serialization/ASTWriter.cpp

if (WritingModule && WritingModule->Directory) {
     } else {
       BaseDir.assign(WritingModule->Directory->getName());
     }
     cleanPathForOutput(Context.getSourceManager().getFileManager(), BaseDir);
 
     // If the home of the module is the current working directory, then we
     // want to pick up the cwd of the build process loading the module, not
     // our cwd, when we load this module.
-    if (!(PP.getHeaderSearchInfo()
+    if (!PP.getHeaderSearchInfo().getHeaderSearchOpts().ModuleFileHomeIsCwd &&
+        (!PP.getHeaderSearchInfo()
               .getHeaderSearchOpts()
               .ModuleMapFileHomeIsCwd ||
-          PP.getHeaderSearchInfo().getHeaderSearchOpts().ModuleFileHomeIsCwd) ||
-        WritingModule->Directory->getName() != StringRef(".")) {
+         WritingModule->Directory->getName() != StringRef("."))) {
       // Module directory.
       auto Abbrev = std::make_shared<BitCodeAbbrev>();
       Abbrev->Add(BitCodeAbbrevOp(MODULE_DIRECTORY));
       Abbrev->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob)); // Directory
       unsigned AbbrevCode = Stream.EmitAbbrev(std::move(Abbrev));
 
       RecordData::value_type Record[] = {MODULE_DIRECTORY};
       Stream.EmitRecordWithBlob(AbbrevCode, Record, BaseDir);

clang/test/Modules/module-file-home-is-cwd.m

 // UNSUPPORTED: target={{.*}}-zos{{.*}}, target={{.*}}-aix{{.*}}
 // RUN: cd %S
 // RUN: %clang_cc1 -x objective-c -fmodules -fno-implicit-modules \
 // RUN:     -fmodule-file-home-is-cwd -fmodule-name=libA -emit-module \
 // RUN:     -fmodules-embed-all-files %S/Inputs/normal-module-map/module.map \
 // RUN:     -o %t/mod.pcm
 // RUN: llvm-bcanalyzer --dump --disable-histogram %t/mod.pcm | FileCheck %s
+// RUN: llvm-bcanalyzer --dump --disable-histogram %t/mod.pcm | FileCheck %s --check-prefix=INPUT
 
-// CHECK: <INPUT_FILE {{.*}}/> blob data = 'Inputs{{/|\\}}normal-module-map{{/|\\}}module.map'
-// CHECK: <INPUT_FILE {{.*}}/> blob data = 'Inputs{{/|\\}}normal-module-map{{/|\\}}a2.h'
-// CHECK: <INPUT_FILE {{.*}}/> blob data = 'Inputs{{/|\\}}normal-module-map{{/|\\}}a1.h'
 // CHECK-NOT: MODULE_DIRECTORY
+// INPUT: <INPUT_FILE {{.*}}/> blob data = 'Inputs{{/|\\}}normal-module-map{{/|\\}}module.map'
+// INPUT: <INPUT_FILE {{.*}}/> blob data = 'Inputs{{/|\\}}normal-module-map{{/|\\}}a2.h'
+// INPUT: <INPUT_FILE {{.*}}/> blob data = 'Inputs{{/|\\}}normal-module-map{{/|\\}}a1.h'
 
 @import libA;
 
 // RUN: cd %t
 // RUN: %clang_cc1 -x objective-c -fmodules -fno-implicit-modules -debug-info-kind=limited \
 // RUN:     -debugger-tuning=lldb -dwarf-ext-refs -fmodule-file-home-is-cwd \
 // RUN:     -fmodule-map-file=%S/Inputs/normal-module-map/module.map \
 // RUN:     -fmodule-file=libA=mod.pcm -emit-llvm -o %t-mod.ll %s
 // RUN: cat %t-mod.ll | FileCheck %s --check-prefix=SKELETON
 
 // SKELETON: !DICompileUnit(language: DW_LANG_ObjC, {{.*}}, splitDebugFilename: "mod.pcm"