[clang] 72c29fa - [C++20] [Modules] [Driver] Emit unused argument warning if we use '-fmodule-output' with non-module input
Chuanqi Xu via cfe-commits
cfe-commits at lists.llvm.org
Wed Apr 3 01:30:17 PDT 2024
Author: Chuanqi Xu
Date: 2024-04-03T16:28:05+08:00
New Revision: 72c29fa9e226a928b3d3a01d74f6b44a0b31b7d4
URL: https://github.com/llvm/llvm-project/commit/72c29fa9e226a928b3d3a01d74f6b44a0b31b7d4
DIFF: https://github.com/llvm/llvm-project/commit/72c29fa9e226a928b3d3a01d74f6b44a0b31b7d4.diff
LOG: [C++20] [Modules] [Driver] Emit unused argument warning if we use '-fmodule-output' with non-module input
We required the file name of an 'importable module unit' should end
with .cppm (or .ccm, .cxxm, .c++m).
But the driver can accept '-fmodule-output' for files with normal
suffixes (e.g., .cpp). This is somewhat inconsistency.
In this patch, we only claim the option `-fmodule-output` is used if
the type of the input file is modules related. Then now the compiler
will emit 'unused argument' warnings if the input file is not modules
related.
Added:
Modified:
clang/docs/ReleaseNotes.rst
clang/lib/Driver/ToolChains/Clang.cpp
clang/test/Driver/module-output.cppm
Removed:
################################################################################
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index d5ce54e185600c..3237842fa1ceb1 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -328,6 +328,9 @@ Improvements to Clang's diagnostics
- New ``-Wformat-signedness`` diagnostic that warn if the format string requires an
unsigned argument and the argument is signed and vice versa.
+- Clang now emits ``unused argument`` warning when the -fmodule-output flag is used
+ with an input that is not of type c++-module.
+
Improvements to Clang's time-trace
----------------------------------
diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
index b03ac6018d2b80..7fd6ad6a47d46f 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -4045,9 +4045,18 @@ static bool RenderModulesOptions(Compilation &C, const Driver &D,
// module fragment.
CmdArgs.push_back("-fskip-odr-check-in-gmf");
- // Claim `-fmodule-output` and `-fmodule-output=` to avoid unused warnings.
- Args.ClaimAllArgs(options::OPT_fmodule_output);
- Args.ClaimAllArgs(options::OPT_fmodule_output_EQ);
+ // We need to include the case the input file is a module file here.
+ // Since the default compilation model for C++ module interface unit will
+ // create temporary module file and compile the temporary module file
+ // to get the object file. Then the `-fmodule-output` flag will be
+ // brought to the second compilation process. So we have to claim it for
+ // the case too.
+ if (Input.getType() == driver::types::TY_CXXModule ||
+ Input.getType() == driver::types::TY_PP_CXXModule ||
+ Input.getType() == driver::types::TY_ModuleFile) {
+ Args.ClaimAllArgs(options::OPT_fmodule_output);
+ Args.ClaimAllArgs(options::OPT_fmodule_output_EQ);
+ }
return HaveModules;
}
diff --git a/clang/test/Driver/module-output.cppm b/clang/test/Driver/module-output.cppm
index d0cab0cbcb31c7..dea9cf998a5401 100644
--- a/clang/test/Driver/module-output.cppm
+++ b/clang/test/Driver/module-output.cppm
@@ -33,6 +33,9 @@
// RUN: %clang -std=c++20 %t/Hello.cppm -fmodule-output=%t/Hello.pcm -fmodule-output -c -fsyntax-only \
// RUN: -### 2>&1 | FileCheck %t/Hello.cppm --check-prefix=CHECK-NOT-USED
+// Test that we can emit a warning if the type of the input file is not a module interface unit.
+// RUN: %clang -std=c++20 %t/a.cpp -fmodule-output -c -o %t/a.o -### 2>&1 | FileCheck %t/a.cpp
+
//--- Hello.cppm
export module Hello;
@@ -55,3 +58,8 @@ export module AnotherModule;
// CHECK: "-emit-obj" {{.*}}"-main-file-name" "Hello.cppm" {{.*}}"-o" "{{.*}}/Hello-{{.*}}.o" "-x" "pcm" "{{.*}}/Hello.pcm"
// CHECK: "-emit-module-interface" {{.*}}"-main-file-name" "AnotherModule.cppm" {{.*}}"-o" "{{.*}}/AnotherModule.pcm" "-x" "c++" "{{.*}}/AnotherModule.cppm"
// CHECK: "-emit-obj" {{.*}}"-main-file-name" "AnotherModule.cppm" {{.*}}"-o" "{{.*}}/AnotherModule-{{.*}}.o" "-x" "pcm" "{{.*}}/AnotherModule.pcm"
+
+//--- a.cpp
+export module a;
+
+// CHECK: warning: argument unused during compilation: '-fmodule-output'
More information about the cfe-commits
mailing list