[PATCH] D133229: [driver] Prune module-map related flags, if they are not going to be needed

[Argyrios Kyrtzidis via Phabricator via cfe-commits]

akyrtzi created this revision.
Herald added a project: All.
akyrtzi requested review of this revision.
Herald added subscribers: cfe-commits, MaskRay.
Herald added a project: clang.

This is follow-up from https://reviews.llvm.org/D132801, but taking into account the conditions
where the module-map flags are still used even when `-fmodules` is disabled.

This useful for removing unnecessary input dependencies from the cc1 invocation.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D133229

Files:
  clang/lib/Driver/ToolChains/Clang.cpp
  clang/test/Driver/modules.m


Index: clang/test/Driver/modules.m
===================================================================
--- clang/test/Driver/modules.m
+++ clang/test/Driver/modules.m
@@ -75,8 +75,13 @@
 // RUN: %clang -fno-modules -fbuild-session-timestamp=123 -### %s 2>&1 | FileCheck -check-prefix=SESSION_FLAG %s
 // SESSION_FLAG-NOT: -fbuild-session-timestamp
 
-// RUN: %clang -fno-modules -fmodules-validate-once-per-build-session -### %s 2>&1 | FileCheck -check-prefix=VALIDATE_ONCE_FLAG %s
-// VALIDATE_ONCE_FLAG-NOT: -fmodules-validate-once-per-build-session
-
-// RUN: %clang -fno-modules -fmodules-validate-system-headers -### %s 2>&1 | FileCheck -check-prefix=VALIDATE_SYSTEM_FLAG %s
-// VALIDATE_SYSTEM_FLAG-NOT: -fmodules-validate-system-headers
+// RUN: %clang -fno-modules -fmodules-validate-once-per-build-session -fmodules-validate-system-headers -fmodule-map-file=module.modulemap \
+// RUN:   -### %s 2>&1 | FileCheck -check-prefix=IGNORED_FLAGS %s
+// IGNORED_FLAGS-NOT: -fmodules-validate-once-per-build-session
+// IGNORED_FLAGS-NOT: -fmodules-validate-system-headers
+// IGNORED_FLAGS-NOT: -fmodule-map-file
+
+// RUN: %clang -fno-modules -fmodules-decluse -fmodule-map-file=module.modulemap -### %s 2>&1 | FileCheck -check-prefix=MMAPFILE %s
+// RUN: %clang -fno-modules -fmodules-strict-decluse -fmodule-map-file=module.modulemap -### %s 2>&1 | FileCheck -check-prefix=MMAPFILE %s
+// RUN: %clang -fno-modules -Xclang -fmodules-local-submodule-visibility -fmodule-map-file=module.modulemap -### %s 2>&1 | FileCheck -check-prefix=MMAPFILE %s
+// MMAPFILE: -fmodule-map-file
Index: clang/lib/Driver/ToolChains/Clang.cpp
===================================================================
--- clang/lib/Driver/ToolChains/Clang.cpp
+++ clang/lib/Driver/ToolChains/Clang.cpp
@@ -3735,23 +3735,47 @@
       CmdArgs.push_back("-fvalidate-ast-input-files-content");
   }
 
-  // -fmodule-name specifies the module that is currently being built (or
-  // used for header checking by -fmodule-maps).
-  Args.AddLastArg(CmdArgs, options::OPT_fmodule_name_EQ);
-
-  // -fmodule-map-file can be used to specify files containing module
-  // definitions.
-  Args.AddAllArgs(CmdArgs, options::OPT_fmodule_map_file);
-
-  // -fbuiltin-module-map can be used to load the clang
-  // builtin headers modulemap file.
-  if (Args.hasArg(options::OPT_fbuiltin_module_map)) {
-    SmallString<128> BuiltinModuleMap(D.ResourceDir);
-    llvm::sys::path::append(BuiltinModuleMap, "include");
-    llvm::sys::path::append(BuiltinModuleMap, "module.modulemap");
-    if (llvm::sys::fs::exists(BuiltinModuleMap))
-      CmdArgs.push_back(
-          Args.MakeArgString("-fmodule-map-file=" + BuiltinModuleMap));
+  // Check whether any "-fmodule-map-file=" flags are relevant or not. This is
+  // useful for pruning the cc1 arguments and removing unnecessary input
+  // dependencies.
+  bool ModuleMapsAreRelevant = [&]() -> bool {
+    if (HaveModules)
+      return true;
+    if (Args.hasFlag(options::OPT_fmodules_decluse,
+                     options::OPT_fno_modules_decluse, false) ||
+        Args.hasFlag(options::OPT_fmodules_strict_decluse,
+                     options::OPT_fno_modules_strict_decluse, false))
+      return true;
+    for (auto Arg : Args.filtered(options::OPT_Xclang)) {
+      if (StringRef(Arg->getValue()) == "-fmodules-local-submodule-visibility")
+        return true;
+    }
+    return false;
+  }();
+
+  if (ModuleMapsAreRelevant) {
+    // -fmodule-name specifies the module that is currently being built (or
+    // used for header checking by -fmodule-maps).
+    Args.AddLastArg(CmdArgs, options::OPT_fmodule_name_EQ);
+
+    // -fmodule-map-file can be used to specify files containing module
+    // definitions.
+    Args.AddAllArgs(CmdArgs, options::OPT_fmodule_map_file);
+
+    // -fbuiltin-module-map can be used to load the clang
+    // builtin headers modulemap file.
+    if (Args.hasArg(options::OPT_fbuiltin_module_map)) {
+      SmallString<128> BuiltinModuleMap(D.ResourceDir);
+      llvm::sys::path::append(BuiltinModuleMap, "include");
+      llvm::sys::path::append(BuiltinModuleMap, "module.modulemap");
+      if (llvm::sys::fs::exists(BuiltinModuleMap))
+        CmdArgs.push_back(
+            Args.MakeArgString("-fmodule-map-file=" + BuiltinModuleMap));
+    }
+  } else {
+    Args.ClaimAllArgs(options::OPT_fmodule_name_EQ);
+    Args.ClaimAllArgs(options::OPT_fmodule_map_file);
+    Args.ClaimAllArgs(options::OPT_fbuiltin_module_map);
   }
 
   // The -fmodule-file=<name>=<file> form specifies the mapping of module


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