https://github.com/jthackray updated https://github.com/llvm/llvm-project/pull/197441
>From dd563d5a7e03ca60f2081396df466f73ae09c1d3 Mon Sep 17 00:00:00 2001 From: Jonathan Thackray <[email protected]> Date: Wed, 13 May 2026 14:03:23 +0100 Subject: [PATCH 1/2] [AArch64][clang] Improve -march= error message with many feature flags When calling `clang` with a large number of feature flags, the entire argument is printed as an error message if one of the feature flags is invalid. For example, before this change, an error message such as this is printed: ``` clang: error: unsupported argument 'armv9.6a+sme2+sme2p1+sve2+sve2p1+profile +crypto+aes+sha2+sha3+sm4+memtag+ssbs+bf16+i8mm+dotprod+ls64+rcpc3+brbe+gcs +faminmax+fp8+fp8fma+fp8dot4+fp8dot2+sme-f8f32+the+lut+lsui+pops+occmo rme-gpc3+d128+invalidfeature' ``` and a user doesn't know which of the `+feature` flags is actually invalid. After this change, the following error message is printed: ``` clang: error: unsupported argument '+invalidfeature' to option '-march=' ``` clearly printing out the invalid feature flag. --- clang/lib/Driver/ToolChains/Arch/AArch64.cpp | 39 ++++++++++++++------ clang/test/Driver/aarch64-march.c | 7 ++++ 2 files changed, 34 insertions(+), 12 deletions(-) diff --git a/clang/lib/Driver/ToolChains/Arch/AArch64.cpp b/clang/lib/Driver/ToolChains/Arch/AArch64.cpp index 93fdbd17d1a43..f42465da14a71 100644 --- a/clang/lib/Driver/ToolChains/Arch/AArch64.cpp +++ b/clang/lib/Driver/ToolChains/Arch/AArch64.cpp @@ -137,8 +137,10 @@ aarch64::getAArch64TargetTuneCPU(const llvm::opt::ArgList &Args, } // Decode AArch64 features from string like +[no]featureA+[no]featureB+... -static bool DecodeAArch64Features(const Driver &D, StringRef text, - llvm::AArch64::ExtensionSet &Extensions) { +static bool +DecodeAArch64Features(const Driver &D, StringRef text, + llvm::AArch64::ExtensionSet &Extensions, + std::optional<std::string> *InvalidArg = nullptr) { SmallVector<StringRef, 8> Split; text.split(Split, StringRef("+"), -1, false); @@ -147,8 +149,11 @@ static bool DecodeAArch64Features(const Driver &D, StringRef text, D.Diag(clang::diag::err_drv_no_neon_modifier); continue; } - if (!Extensions.parseModifier(Feature)) + if (!Extensions.parseModifier(Feature)) { + if (InvalidArg) + InvalidArg->emplace(("+" + Feature).str()); return false; + } } return true; @@ -203,7 +208,8 @@ static bool DecodeAArch64Mcpu(const Driver &D, StringRef Mcpu, static bool getAArch64ArchFeaturesFromMarch(const Driver &D, StringRef March, const ArgList &Args, - llvm::AArch64::ExtensionSet &Extensions) { + llvm::AArch64::ExtensionSet &Extensions, + std::optional<std::string> &InvalidArg) { std::string MarchLowerCase = March.lower(); std::pair<StringRef, StringRef> Split = StringRef(MarchLowerCase).split("+"); @@ -212,13 +218,15 @@ getAArch64ArchFeaturesFromMarch(const Driver &D, StringRef March, const llvm::AArch64::ArchInfo *ArchInfo = llvm::AArch64::parseArch(Split.first); - if (!ArchInfo) + if (!ArchInfo) { + InvalidArg.emplace(Split.first.str()); return false; + } Extensions.addArchDefaults(*ArchInfo); if ((Split.second.size() && - !DecodeAArch64Features(D, Split.second, Extensions))) + !DecodeAArch64Features(D, Split.second, Extensions, &InvalidArg))) return false; return true; @@ -253,6 +261,7 @@ void aarch64::getAArch64TargetFeatures(const Driver &D, bool ForAS, bool ForMultilib) { Arg *A; bool success = true; + std::optional<std::string> InvalidArg; llvm::StringRef WaMArch; llvm::AArch64::ExtensionSet Extensions; if (ForAS) @@ -265,10 +274,11 @@ void aarch64::getAArch64TargetFeatures(const Driver &D, // "-Xassembler -march" is detected. Otherwise it may return false // and causes Clang to error out. if (!WaMArch.empty()) - success = getAArch64ArchFeaturesFromMarch(D, WaMArch, Args, Extensions); + success = getAArch64ArchFeaturesFromMarch(D, WaMArch, Args, Extensions, + InvalidArg); else if ((A = Args.getLastArg(options::OPT_march_EQ))) - success = - getAArch64ArchFeaturesFromMarch(D, A->getValue(), Args, Extensions); + success = getAArch64ArchFeaturesFromMarch(D, A->getValue(), Args, + Extensions, InvalidArg); else if ((A = Args.getLastArg(options::OPT_mcpu_EQ))) success = getAArch64ArchFeaturesFromMcpu(D, A->getValue(), Args, Extensions); @@ -277,7 +287,8 @@ void aarch64::getAArch64TargetFeatures(const Driver &D, D, getAArch64TargetCPUByTriple(Triple), Args, Extensions); else // Default to 'A' profile if the architecture is not specified. - success = getAArch64ArchFeaturesFromMarch(D, "armv8-a", Args, Extensions); + success = getAArch64ArchFeaturesFromMarch(D, "armv8-a", Args, Extensions, + InvalidArg); if (success && (A = Args.getLastArg(options::OPT_mtune_EQ))) success = getAArch64MicroArchFeaturesFromMtune(D, A->getValue(), Args); @@ -292,10 +303,14 @@ void aarch64::getAArch64TargetFeatures(const Driver &D, auto Diag = D.Diag(diag::err_drv_unsupported_option_argument); // 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()) + if (!WaMArch.empty() && InvalidArg) + Diag << "-march=" << *InvalidArg; + else if (!WaMArch.empty()) Diag << "-march=" << WaMArch; - else + else if (!InvalidArg) Diag << A->getSpelling() << A->getValue(); + else + Diag << A->getSpelling() << *InvalidArg; } // -mgeneral-regs-only disables all floating-point features. diff --git a/clang/test/Driver/aarch64-march.c b/clang/test/Driver/aarch64-march.c index 132cea0e2c624..a28dca85807b7 100644 --- a/clang/test/Driver/aarch64-march.c +++ b/clang/test/Driver/aarch64-march.c @@ -29,3 +29,10 @@ // RUN: %clang --target=aarch64_be -mbig-endian -march=ARMv8.1a -### -c %s 2>&1 | FileCheck -check-prefix=GENERICV81A-BE %s // RUN: %clang --target=aarch64_be -mbig-endian -march=ARMV8.1-a -### -c %s 2>&1 | FileCheck -check-prefix=GENERICV81A-BE %s // GENERICV81A-BE: "-cc1"{{.*}} "-triple" "aarch64_be{{.*}}" "-target-cpu" "generic" "-target-feature" "+v8.1a" + +// ================== Check whether -march diagnoses the specific invalid argument. +// RUN: not %clang --target=aarch64 -march=armv9.6-a+sme2+sme2p1+sve2+sve2p1+badfeature+aes+sha2+memtag+bf16 %s -### -c 2>&1 | FileCheck -check-prefix=INVALID-EXT %s +// RUN: not %clang --target=aarch64 -march=notanarch+sme2 %s -### -c 2>&1 | FileCheck -check-prefix=INVALID-ARCH %s +// INVALID-EXT: error: unsupported argument '+badfeature' to option '-march=' +// INVALID-EXT-NOT: armv9.6-a+sme2+sme2p1+sve2+sve2p1+badfeature+aes+sha2+memtag+bf16 +// INVALID-ARCH: error: unsupported argument 'notanarch' to option '-march=' >From 5a0e4013a1eb60927c3dcd35f17a7a5fee3b9179 Mon Sep 17 00:00:00 2001 From: Jonathan Thackray <[email protected]> Date: Thu, 14 May 2026 11:00:00 +0100 Subject: [PATCH 2/2] fixup! Adjust test comment --- clang/test/Driver/aarch64-march.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/clang/test/Driver/aarch64-march.c b/clang/test/Driver/aarch64-march.c index a28dca85807b7..d2cea0e50def3 100644 --- a/clang/test/Driver/aarch64-march.c +++ b/clang/test/Driver/aarch64-march.c @@ -30,7 +30,7 @@ // RUN: %clang --target=aarch64_be -mbig-endian -march=ARMV8.1-a -### -c %s 2>&1 | FileCheck -check-prefix=GENERICV81A-BE %s // GENERICV81A-BE: "-cc1"{{.*}} "-triple" "aarch64_be{{.*}}" "-target-cpu" "generic" "-target-feature" "+v8.1a" -// ================== Check whether -march diagnoses the specific invalid argument. +// ================== Check whether -march diagnoses the first invalid argument. // RUN: not %clang --target=aarch64 -march=armv9.6-a+sme2+sme2p1+sve2+sve2p1+badfeature+aes+sha2+memtag+bf16 %s -### -c 2>&1 | FileCheck -check-prefix=INVALID-EXT %s // RUN: not %clang --target=aarch64 -march=notanarch+sme2 %s -### -c 2>&1 | FileCheck -check-prefix=INVALID-ARCH %s // INVALID-EXT: error: unsupported argument '+badfeature' to option '-march=' _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
