[clang] 646e502 - [clang] add -fmodule-file-home-is-cwd

[Richard Howell via cfe-commits]

Author: Richard Howell
Date: 2022-05-12T07:27:47-07:00
New Revision: 646e502de0d854cb3ecaca90ab52bebfe59a40cd

URL: https://github.com/llvm/llvm-project/commit/646e502de0d854cb3ecaca90ab52bebfe59a40cd
DIFF: https://github.com/llvm/llvm-project/commit/646e502de0d854cb3ecaca90ab52bebfe59a40cd.diff

LOG: [clang] add -fmodule-file-home-is-cwd

This diff adds a new frontend flag `-fmodule-file-home-is-cwd`.
The behavior of this flag is similar to
`-fmodule-map-file-home-is-cwd` but does not require the module
map files to be modified to have inputs relative to the cwd.
Instead the output modules will have their `BaseDirectory` set
to the cwd and will try and resolve paths relative to that.

The motiviation for this change is to support relocatable pcm
files that are built on different machines with different paths
without having to alter module map files, which is sometimes not
possible as they are provided by 3rd parties.

Reviewed By: urnathan

Differential Revision: https://reviews.llvm.org/D124874

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

Modified: 
    clang/include/clang/Driver/Options.td
    clang/include/clang/Lex/HeaderSearchOptions.h
    clang/lib/Serialization/ASTWriter.cpp

Removed: 
    


################################################################################
diff  --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
index 8e840ede926a9..6668ac4ca9470 100644
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -5619,6 +5619,10 @@ def fmodule_map_file_home_is_cwd : Flag<["-"], "fmodule-map-file-home-is-cwd">,
   HelpText<"Use the current working directory as the home directory of "
            "module maps specified by -fmodule-map-file=<FILE>">,
   MarshallingInfoFlag<HeaderSearchOpts<"ModuleMapFileHomeIsCwd">>;
+def fmodule_file_home_is_cwd : Flag<["-"], "fmodule-file-home-is-cwd">,
+  HelpText<"Use the current working directory as the base directory of "
+           "compiled module files.">,
+  MarshallingInfoFlag<HeaderSearchOpts<"ModuleFileHomeIsCwd">>;
 def fmodule_feature : Separate<["-"], "fmodule-feature">,
   MetaVarName<"<feature>">,
   HelpText<"Enable <feature> in module map requires declarations">,

diff  --git a/clang/include/clang/Lex/HeaderSearchOptions.h b/clang/include/clang/Lex/HeaderSearchOptions.h
index 4efdfc26c3c67..6436a9b3bde20 100644
--- a/clang/include/clang/Lex/HeaderSearchOptions.h
+++ b/clang/include/clang/Lex/HeaderSearchOptions.h
@@ -143,6 +143,12 @@ class HeaderSearchOptions {
   /// file.
   unsigned ModuleMapFileHomeIsCwd : 1;
 
+  /// Set the base path of a built module file to be the current working
+  /// directory. This is useful for sharing module files across machines
+  /// that build with 
diff erent paths without having to rewrite all
+  /// modulemap files to have working directory relative paths.
+  unsigned ModuleFileHomeIsCwd : 1;
+
   /// Also search for prebuilt implicit modules in the prebuilt module cache
   /// path.
   unsigned EnablePrebuiltImplicitModules : 1;
@@ -222,9 +228,9 @@ class HeaderSearchOptions {
   HeaderSearchOptions(StringRef _Sysroot = "/")
       : Sysroot(_Sysroot), ModuleFormat("raw"), DisableModuleHash(false),
         ImplicitModuleMaps(false), ModuleMapFileHomeIsCwd(false),
-        EnablePrebuiltImplicitModules(false), UseBuiltinIncludes(true),
-        UseStandardSystemIncludes(true), UseStandardCXXIncludes(true),
-        UseLibcxx(false), Verbose(false),
+        ModuleFileHomeIsCwd(false), EnablePrebuiltImplicitModules(false),
+        UseBuiltinIncludes(true), UseStandardSystemIncludes(true),
+        UseStandardCXXIncludes(true), UseLibcxx(false), Verbose(false),
         ModulesValidateOncePerBuildSession(false),
         ModulesValidateSystemHeaders(false),
         ValidateASTInputFilesContent(false), UseDebugInfo(false),

diff  --git a/clang/lib/Serialization/ASTWriter.cpp b/clang/lib/Serialization/ASTWriter.cpp
index 228bd9aa08db4..e42f41f8fbc2d 100644
--- a/clang/lib/Serialization/ASTWriter.cpp
+++ b/clang/lib/Serialization/ASTWriter.cpp
@@ -1224,15 +1224,24 @@ void ASTWriter::WriteControlBlock(Preprocessor &PP, ASTContext &Context,
   }
 
   if (WritingModule && WritingModule->Directory) {
-    SmallString<128> BaseDir(WritingModule->Directory->getName());
+    SmallString<128> BaseDir;
+    if (PP.getHeaderSearchInfo().getHeaderSearchOpts().ModuleFileHomeIsCwd) {
+      // Use the current working directory as the base path for all inputs.
+      auto *CWD =
+          Context.getSourceManager().getFileManager().getDirectory(".").get();
+      BaseDir.assign(CWD->getName());
+    } 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()
-             .getHeaderSearchOpts()
-             .ModuleMapFileHomeIsCwd ||
+    if (!(PP.getHeaderSearchInfo()
+              .getHeaderSearchOpts()
+              .ModuleMapFileHomeIsCwd ||
+          PP.getHeaderSearchInfo().getHeaderSearchOpts().ModuleFileHomeIsCwd) ||
         WritingModule->Directory->getName() != StringRef(".")) {
       // Module directory.
       auto Abbrev = std::make_shared<BitCodeAbbrev>();

diff  --git a/clang/test/Modules/module-file-home-is-cwd.m b/clang/test/Modules/module-file-home-is-cwd.m
new file mode 100644
index 0000000000000..c455d647da3f1
--- /dev/null
+++ b/clang/test/Modules/module-file-home-is-cwd.m
@@ -0,0 +1,8 @@
+// RUN: cd %S
+// RUN: %clang_cc1 -fmodules -fno-implicit-modules -fmodule-file-home-is-cwd -fmodule-name=libA -emit-module Inputs/normal-module-map/module.map -o %t/mod.pcm
+// RUN: llvm-bcanalyzer --dump --disable-histogram %t/mod.pcm | FileCheck %s
+
+// CHECK: <INPUT_FILE {{.*}}/> blob data = 'Inputs{{/|\\}}normal-module-map{{/|\\}}a1.h'
+// CHECK: <INPUT_FILE {{.*}}/> blob data = 'Inputs{{/|\\}}normal-module-map{{/|\\}}a2.h'
+// CHECK: <INPUT_FILE {{.*}}/> blob data = 'Inputs{{/|\\}}normal-module-map{{/|\\}}module.map'
+// CHECK-NOT: MODULE_DIRECTORY