[clang] be8180a - [clang][driver] Warn when '-mno-outline-atomics' is used with a non-AArch64 triple
Nathan Chancellor via cfe-commits
cfe-commits at lists.llvm.org
Thu Dec 23 11:49:17 PST 2021
Author: Nathan Chancellor
Date: 2021-12-23T12:36:42-07:00
New Revision: be8180af5854806a343c3dd334d97ba2c4bfadfa
URL: https://github.com/llvm/llvm-project/commit/be8180af5854806a343c3dd334d97ba2c4bfadfa
DIFF: https://github.com/llvm/llvm-project/commit/be8180af5854806a343c3dd334d97ba2c4bfadfa.diff
LOG: [clang][driver] Warn when '-mno-outline-atomics' is used with a non-AArch64 triple
The Linux kernel has a make macro called cc-option that invokes the
compiler with an option in isolation to see if it is supported before
adding it to CFLAGS. The exit code of the compiler is used to determine
if the flag is supported and should be added to the compiler invocation.
A call to cc-option with '-mno-outline-atomics' was added to prevent
linking errors with newer GCC versions but this call succeeds with a
non-AArch64 target because there is no warning from clang with
'-mno-outline-atomics', just '-moutline-atomics'. Because the call
succeeds and adds '-mno-outline-atomics' to the compiler invocation,
there is a warning from LLVM because the 'outline-atomics target
feature is only supported by the AArch64 backend.
$ echo | clang -target x86_64 -moutline-atomics -Werror -x c -c -o /dev/null -
clang-14: error: The 'x86_64' architecture does not support -moutline-atomics; flag ignored [-Werror,-Woption-ignored]
$ echo $?
1
$ echo | clang -target x86_64 -mno-outline-atomics -Werror -x c -c -o /dev/null -
'-outline-atomics' is not a recognized feature for this target (ignoring feature)
$ echo $?
0
This does not match GCC's behavior, which errors when the flag is added
to a non-AArch64 target.
$ echo | gcc -moutline-atomics -x c -c -o /dev/null -
gcc: error: unrecognized command-line option ‘-moutline-atomics’; did you mean ‘-finline-atomics’?
$ echo | gcc -mno-outline-atomics -x c -c -o /dev/null -
gcc: error: unrecognized command-line option ‘-mno-outline-atomics’; did you mean ‘-fno-inline-atomics’?
$ echo | aarch64-linux-gnu-gcc -moutline-atomics -x c -c -o /dev/null -
$ echo | aarch64-linux-gnu-gcc -mno-outline-atomics -x c -c -o /dev/null -
To get closer to GCC's behavior, issue a warning when
'-mno-outline-atomics' is used without an AArch64 triple and do not add
'{-,+}outline-atomic" to the list of target features in these cases.
Link: https://github.com/ClangBuiltLinux/linux/issues/1552
Reviewed By: melver, nickdesaulniers
Differential Revision: https://reviews.llvm.org/D116128
Added:
clang/test/Driver/unsupported-outline-atomics.c
Modified:
clang/include/clang/Basic/DiagnosticDriverKinds.td
clang/lib/Driver/ToolChains/Clang.cpp
Removed:
################################################################################
diff --git a/clang/include/clang/Basic/DiagnosticDriverKinds.td b/clang/include/clang/Basic/DiagnosticDriverKinds.td
index 3025e6fe3c02d..c623aeff11f05 100644
--- a/clang/include/clang/Basic/DiagnosticDriverKinds.td
+++ b/clang/include/clang/Basic/DiagnosticDriverKinds.td
@@ -568,7 +568,7 @@ def warn_drv_moutline_unsupported_opt : Warning<
InGroup<OptionIgnored>;
def warn_drv_moutline_atomics_unsupported_opt : Warning<
- "'%0' does not support '-moutline-atomics'; flag ignored">,
+ "'%0' does not support '-%1'; flag ignored">,
InGroup<OptionIgnored>;
def warn_drv_darwin_sdk_invalid_settings : Warning<
diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
index ca62229b8153e..65347a38490ee 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -7007,18 +7007,18 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
if (Arg *A = Args.getLastArg(options::OPT_moutline_atomics,
options::OPT_mno_outline_atomics)) {
- if (A->getOption().matches(options::OPT_moutline_atomics)) {
- // Option -moutline-atomics supported for AArch64 target only.
- if (!Triple.isAArch64()) {
- D.Diag(diag::warn_drv_moutline_atomics_unsupported_opt)
- << Triple.getArchName();
- } else {
+ // Option -moutline-atomics supported for AArch64 target only.
+ if (!Triple.isAArch64()) {
+ D.Diag(diag::warn_drv_moutline_atomics_unsupported_opt)
+ << Triple.getArchName() << A->getOption().getName();
+ } else {
+ if (A->getOption().matches(options::OPT_moutline_atomics)) {
CmdArgs.push_back("-target-feature");
CmdArgs.push_back("+outline-atomics");
+ } else {
+ CmdArgs.push_back("-target-feature");
+ CmdArgs.push_back("-outline-atomics");
}
- } else {
- CmdArgs.push_back("-target-feature");
- CmdArgs.push_back("-outline-atomics");
}
} else if (Triple.isAArch64() &&
getToolChain().IsAArch64OutlineAtomicsDefault(Args)) {
diff --git a/clang/test/Driver/unsupported-outline-atomics.c b/clang/test/Driver/unsupported-outline-atomics.c
new file mode 100644
index 0000000000000..2e88528c2ec60
--- /dev/null
+++ b/clang/test/Driver/unsupported-outline-atomics.c
@@ -0,0 +1,15 @@
+// RUN: %clang -target x86_64 -moutline-atomics -S %s -### 2>&1 | FileCheck %s -check-prefix=CHECK-OUTLINE-ATOMICS-X86
+// CHECK-OUTLINE-ATOMICS-X86: warning: 'x86_64' does not support '-moutline-atomics'; flag ignored [-Woption-ignored]
+// CHECK-OUTLINE-ATOMICS-X86-NOT: "-target-feature" "+outline-atomics"
+
+// RUN: %clang -target x86_64 -mno-outline-atomics -S %s -### 2>&1 | FileCheck %s -check-prefix=CHECK-NO-OUTLINE-ATOMICS-X86
+// CHECK-NO-OUTLINE-ATOMICS-X86: warning: 'x86_64' does not support '-mno-outline-atomics'; flag ignored [-Woption-ignored]
+// CHECK-NO-OUTLINE-ATOMICS-X86-NOT: "-target-feature" "-outline-atomics"
+
+// RUN: %clang -target riscv64 -moutline-atomics -S %s -### 2>&1 | FileCheck %s -check-prefix=CHECK-OUTLINE-ATOMICS-RISCV
+// CHECK-OUTLINE-ATOMICS-RISCV: warning: 'riscv64' does not support '-moutline-atomics'; flag ignored [-Woption-ignored]
+// CHECK-OUTLINE-ATOMICS-RISCV-NOT: "-target-feature" "+outline-atomics"
+
+// RUN: %clang -target riscv64 -mno-outline-atomics -S %s -### 2>&1 | FileCheck %s -check-prefix=CHECK-NO-OUTLINE-ATOMICS-RISCV
+// CHECK-NO-OUTLINE-ATOMICS-RISCV: warning: 'riscv64' does not support '-mno-outline-atomics'; flag ignored [-Woption-ignored]
+// CHECK-NO-OUTLINE-ATOMICS-RISCV-NOT: "-target-feature" "-outline-atomics"
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