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[AArch64] Avoid crashing on invalid -Wa,-march= values 

As reported in https://bugs.freebsd.org/260078, the gnutls Makefiles
pass -Wa,-march=all to compile a number of assembly files. Clang does
not support this -march value, but because of a mistake in handling
the arguments, an unitialized Arg pointer is dereferenced, which can
cause a segfault.

Work around this by adding a check if the local WaMArch variable is
initialized, and if so, using its value in the diagnostic message.

Reviewed By: tschuett

Differential Revision: https://reviews.llvm.org/D114677
This commit is contained in:
Dimitry Andric 2021-11-28 18:09:06 +01:00
parent 3608e18a94
commit df08b2fe8b
2 changed files with 20 additions and 4 deletions
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15
clang/lib/Driver/ToolChains/Arch/AArch64.cpp
View File

@ -225,7 +225,7 @@ void aarch64::getAArch64TargetFeatures(const Driver &D,
bool success = true;
// Enable NEON by default.
Features.push_back("+neon");
llvm::StringRef WaMArch = "";
llvm::StringRef WaMArch;
if (ForAS)
for (const auto *A :
Args.filtered(options::OPT_Wa_COMMA, options::OPT_Xassembler))
@ -235,7 +235,7 @@ void aarch64::getAArch64TargetFeatures(const Driver &D,
// Call getAArch64ArchFeaturesFromMarch only if "-Wa,-march=" or
// "-Xassembler -march" is detected. Otherwise it may return false
// and causes Clang to error out.
if (WaMArch.size())
if (!WaMArch.empty())
success = getAArch64ArchFeaturesFromMarch(D, WaMArch, Args, Features);
else if ((A = Args.getLastArg(options::OPT_march_EQ)))
success = getAArch64ArchFeaturesFromMarch(D, A->getValue(), Args, Features);
@ -259,8 +259,15 @@ void aarch64::getAArch64TargetFeatures(const Driver &D,
success = getAArch64MicroArchFeaturesFromMcpu(
D, getAArch64TargetCPU(Args, Triple, A), Args, Features);
if (!success)
D.Diag(diag::err_drv_clang_unsupported) << A->getAsString(Args);
if (!success) {
auto Diag = D.Diag(diag::err_drv_clang_unsupported);
// If "-Wa,-march=" is used, 'WaMArch' will contain the argument's value,
// while 'A' is uninitialized. Only dereference 'A' in the other case.
if (!WaMArch.empty())
Diag << "-march=" + WaMArch.str();
else
Diag << A->getAsString(Args);
}
if (Args.getLastArg(options::OPT_mgeneral_regs_only)) {
Features.push_back("-fp-armv8");

9
clang/test/Driver/aarch64-target-as-march.s
View File

@ -44,3 +44,12 @@
// TARGET-FEATURE-3-NOT: "-target-feature" "+v8.4a"
// TARGET-FEATURE-4: "-target-feature" "+v8.4a"
// TARGET-FEATURE-4-NOT: "-target-feature" "+v8.3a"
// Invalid -march settings
// RUN: %clang --target=aarch64-linux-gnueabi -### -c -Wa,-march=all %s 2>&1 | \
// RUN: FileCheck --check-prefix=INVALID-ARCH-1 %s
// RUN: %clang --target=aarch64-linux-gnueabi -### -c -Wa,-march=foobar %s 2>&1 | \
// RUN: FileCheck --check-prefix=INVALID-ARCH-2 %s
// INVALID-ARCH-1: error: the clang compiler does not support '-march=all'
// INVALID-ARCH-2: error: the clang compiler does not support '-march=foobar'