mstorsjo created this revision.
mstorsjo added reviewers: aaron.ballman, sepavloff, phosek, MaskRay.
Herald added a subscriber: dang.
mstorsjo requested review of this revision.
Herald added a project: clang.
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 it 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.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D116503
Files:
clang/docs/ClangCommandLineReference.rst
clang/include/clang/Driver/Options.td
clang/lib/Driver/Driver.cpp
clang/test/Driver/diagnostics.c
Index: clang/test/Driver/diagnostics.c
===================================================================
--- clang/test/Driver/diagnostics.c
+++ clang/test/Driver/diagnostics.c
@@ -1,9 +1,44 @@
// Parse diagnostic arguments in the driver
// PR12181
+// Exactly which arguments are warned about and which aren't differ 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.
+
+// 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 -fzyzzybalubah \
-// RUN: -Werror=unused-command-line-argument %s
+// 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 different argument, it
+// still warns about the unused argument.
// RUN: not %clang -target x86_64-apple-darwin10 \
-// RUN: -fsyntax-only -fzyzzybalubah -Werror %s
+// RUN: --start-no-unused-arguments -fsyntax-only --end-no-unused-arguments \
+// RUN: -lfoo -Werror %s 2>&1 | FileCheck %s
+
+// CHECK: -lfoo: 'linker' input unused
Index: clang/lib/Driver/Driver.cpp
===================================================================
--- clang/lib/Driver/Driver.cpp
+++ clang/lib/Driver/Driver.cpp
@@ -367,7 +367,20 @@
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').
Index: clang/include/clang/Driver/Options.td
===================================================================
--- clang/include/clang/Driver/Options.td
+++ clang/include/clang/Driver/Options.td
@@ -1076,6 +1076,8 @@
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<[NoXarchOption, 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 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<[NoXarchOption, 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]>;
Index: clang/docs/ClangCommandLineReference.rst
===================================================================
--- clang/docs/ClangCommandLineReference.rst
+++ clang/docs/ClangCommandLineReference.rst
@@ -1337,6 +1337,10 @@
.. option:: -Wnonportable-cfstrings<arg>, -Wno-nonportable-cfstrings<arg>
+.. option:: --start-no-unused-arguments, --end-no-unused-arguments
+
+Don't warn for unused arguments between these arguments.
+
Target-independent compilation options
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.. option:: -Wframe-larger-than=<arg>
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