[clang] 50ec130 - [clang] Add --start-no-unused-arguments/--end-no-unused-arguments to silence some unused argument warnings
Martin Storsjö via cfe-commits
cfe-commits at lists.llvm.org
Mon Jan 10 23:22:26 PST 2022
Author: Martin Storsjö
Date: 2022-01-11T09:22:00+02:00
New Revision: 50ec1306d060e46e0d53c9f5d8a052e1b0d10d3b
URL: https://github.com/llvm/llvm-project/commit/50ec1306d060e46e0d53c9f5d8a052e1b0d10d3b
DIFF: https://github.com/llvm/llvm-project/commit/50ec1306d060e46e0d53c9f5d8a052e1b0d10d3b.diff
LOG: [clang] Add --start-no-unused-arguments/--end-no-unused-arguments to silence some unused argument warnings
When passing a set of flags to configure defaults for a specific
target (similar to the cmake settings `CLANG_DEFAULT_RTLIB`,
`CLANG_DEFAULT_UNWINDLIB`, `CLANG_DEFAULT_CXX_STDLIB` and
`CLANG_DEFAULT_LINKER`, but without hardcoding them in the binary),
some of the flags may cause warnings (e.g. `-stdlib=` when compiling C
code). Allow requesting selectively ignoring unused arguments among
some of the arguments on the command line, without needing to resort
to `-Qunused-arguments` or `-Wno-unused-command-line-argument`.
Fix up the existing diagnostics.c testcase. It was added in
response to PR12181 to fix handling of
`-Werror=unused-command-line-argument`, but the command line option
in the test (`-fzyzzybalubah`) now triggers "error: unknown argument"
instead of the intended warning. Change it into a linker input
(`-lfoo`) which triggers the intended diagnostic. Extend the
existing test case to check more cases and make sure that it keeps
testing the intended case.
Add testing of the new option to this existing test.
Differential Revision: https://reviews.llvm.org/D116503
Added:
Modified:
clang/docs/ClangCommandLineReference.rst
clang/include/clang/Driver/Options.td
clang/lib/Driver/Driver.cpp
clang/test/Driver/diagnostics.c
Removed:
################################################################################
diff --git a/clang/docs/ClangCommandLineReference.rst b/clang/docs/ClangCommandLineReference.rst
index 72d571dd10ee3..8ae7d7f49f168 100644
--- a/clang/docs/ClangCommandLineReference.rst
+++ b/clang/docs/ClangCommandLineReference.rst
@@ -212,6 +212,10 @@ Enable linker job to emit a static library.
Trivial automatic variable initialization to zero is only here for benchmarks, it'll eventually be removed, and I'm OK with that because I'm only using it to benchmark
+.. option:: --end-no-unused-arguments
+
+Start emitting warnings for unused driver arguments
+
.. option:: -exported\_symbols\_list <arg>
.. option:: -faligned-new=<arg>
@@ -663,6 +667,10 @@ Dynamically link the sanitizer runtime
.. option:: -single\_module
+.. option:: --start-no-unused-arguments
+
+Don't emit warnings about unused arguments for the following arguments
+
.. option:: -static-libgcc
.. option:: -static-libsan
diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
index 6c56d9739de2a..4bcb7bd4c3969 100644
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -1076,6 +1076,8 @@ def emit_interface_stubs : Flag<["-"], "emit-interface-stubs">, Flags<[CC1Option
def emit_merged_ifs : Flag<["-"], "emit-merged-ifs">,
Flags<[CC1Option]>, Group<Action_Group>,
HelpText<"Generate Interface Stub Files, emit merged text not binary.">;
+def end_no_unused_arguments : Flag<["--"], "end-no-unused-arguments">, Flags<[CoreOption]>,
+ HelpText<"Start emitting warnings for unused driver arguments">;
def interface_stub_version_EQ : JoinedOrSeparate<["-"], "interface-stub-version=">, Flags<[CC1Option]>;
def exported__symbols__list : Separate<["-"], "exported_symbols_list">;
def e : JoinedOrSeparate<["-"], "e">, Flags<[LinkerInput]>, Group<Link_Group>;
@@ -3913,6 +3915,8 @@ def shared : Flag<["-", "--"], "shared">, Group<Link_Group>;
def single__module : Flag<["-"], "single_module">;
def specs_EQ : Joined<["-", "--"], "specs=">, Group<Link_Group>;
def specs : Separate<["-", "--"], "specs">, Flags<[Unsupported]>;
+def start_no_unused_arguments : Flag<["--"], "start-no-unused-arguments">, Flags<[CoreOption]>,
+ HelpText<"Don't emit warnings about unused arguments for the following arguments">;
def static_libgcc : Flag<["-"], "static-libgcc">;
def static_libstdcxx : Flag<["-"], "static-libstdc++">;
def static : Flag<["-", "--"], "static">, Group<Link_Group>, Flags<[NoArgumentUnused]>;
diff --git a/clang/lib/Driver/Driver.cpp b/clang/lib/Driver/Driver.cpp
index ac8438bb45a6a..2c3b137554c0b 100644
--- a/clang/lib/Driver/Driver.cpp
+++ b/clang/lib/Driver/Driver.cpp
@@ -367,7 +367,20 @@ DerivedArgList *Driver::TranslateInputArgs(const InputArgList &Args) const {
bool HasNostdlib = Args.hasArg(options::OPT_nostdlib);
bool HasNostdlibxx = Args.hasArg(options::OPT_nostdlibxx);
bool HasNodefaultlib = Args.hasArg(options::OPT_nodefaultlibs);
+ bool IgnoreUnused = false;
for (Arg *A : Args) {
+ if (IgnoreUnused)
+ A->claim();
+
+ if (A->getOption().matches(options::OPT_start_no_unused_arguments)) {
+ IgnoreUnused = true;
+ continue;
+ }
+ if (A->getOption().matches(options::OPT_end_no_unused_arguments)) {
+ IgnoreUnused = false;
+ continue;
+ }
+
// Unfortunately, we have to parse some forwarding options (-Xassembler,
// -Xlinker, -Xpreprocessor) because we either integrate their functionality
// (assembler and preprocessor), or bypass a previous driver ('collect2').
diff --git a/clang/test/Driver/diagnostics.c b/clang/test/Driver/diagnostics.c
index 8500fad89d838..16e00345eb518 100644
--- a/clang/test/Driver/diagnostics.c
+++ b/clang/test/Driver/diagnostics.c
@@ -1,9 +1,53 @@
// Parse diagnostic arguments in the driver
-// PR12181
-// RUN: not %clang -target x86_64-apple-darwin10 \
-// RUN: -fsyntax-only -fzyzzybalubah \
-// RUN: -Werror=unused-command-line-argument %s
+// Exactly which arguments are warned about and which aren't
diff er based
+// on what target is selected. -stdlib= and -fuse-ld= emit diagnostics when
+// compiling C code, for e.g. *-linux-gnu. Linker inputs, like -lfoo, emit
+// diagnostics when only compiling for all targets.
-// RUN: not %clang -target x86_64-apple-darwin10 \
-// RUN: -fsyntax-only -fzyzzybalubah -Werror %s
+// This is normally a non-fatal warning:
+// RUN: %clang --target=x86_64-apple-darwin10 \
+// RUN: -fsyntax-only -lfoo %s 2>&1 | FileCheck %s
+
+// Either with a specific -Werror=unused.. or a blanket -Werror, this
+// causes the command to fail.
+// RUN: not %clang --target=x86_64-apple-darwin10 \
+// RUN: -fsyntax-only -lfoo \
+// RUN: -Werror=unused-command-line-argument %s 2>&1 | FileCheck %s
+
+// RUN: not %clang --target=x86_64-apple-darwin10 \
+// RUN: -fsyntax-only -lfoo -Werror %s 2>&1 | FileCheck %s
+
+// With a specific -Wno-..., no diagnostic should be printed.
+// RUN: %clang --target=x86_64-apple-darwin10 \
+// RUN: -fsyntax-only -lfoo -Werror \
+// RUN: -Wno-unused-command-line-argument %s 2>&1 | count 0
+
+// With -Qunused-arguments, no diagnostic should be printed.
+// RUN: %clang --target=x86_64-apple-darwin10 \
+// RUN: -fsyntax-only -lfoo -Werror \
+// RUN: -Qunused-arguments %s 2>&1 | count 0
+
+// With the argument enclosed in --{start,end}-no-unused-arguments,
+// there's no diagnostic.
+// RUN: %clang --target=x86_64-apple-darwin10 -fsyntax-only \
+// RUN: --start-no-unused-arguments -lfoo --end-no-unused-arguments \
+// RUN: -Werror %s 2>&1 | count 0
+
+// With --{start,end}-no-unused-argument around a
diff erent argument, it
+// still warns about the unused argument.
+// RUN: not %clang --target=x86_64-apple-darwin10 \
+// RUN: --start-no-unused-arguments -fsyntax-only --end-no-unused-arguments \
+// RUN: -lfoo -Werror %s 2>&1 | FileCheck %s
+
+// Test clang-cl warning about unused linker options.
+// RUN: not %clang_cl -fsyntax-only /WX %s \
+// RUN: -link 2>&1 | FileCheck %s --check-prefix=CL-WARNING
+
+// Test clang-cl ignoring the warning with --start-no-unused-arguments.
+// RUN: %clang_cl -fsyntax-only /WX %s \
+// RUN: --start-no-unused-arguments -link --end-no-unused-arguments 2>&1 | count 0
+
+// CHECK: -lfoo: 'linker' input unused
+
+// CL-WARNING: argument unused during compilation: '-link'
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