Skip to content

[Clang] Determine offloading architectures at Toolchain creation #145799

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 1 commit into from
Jun 26, 2025
Merged

[Clang] Determine offloading architectures at Toolchain creation #145799

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
13 changes: 6 additions & 7 deletions clang/include/clang/Driver/Driver.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -367,10 +367,9 @@ class Driver {
/// stored in it, and will clean them up when torn down.
mutable llvm::StringMap<std::unique_ptr<ToolChain>> ToolChains;

/// Cache of known offloading architectures for the ToolChain already derived.
/// This should only be modified when we first initialize the offloading
/// toolchains.
llvm::DenseMap<const ToolChain *, llvm::DenseSet<llvm::StringRef>> KnownArchs;
/// The associated offloading architectures with each toolchain.
llvm::DenseMap<const ToolChain *, llvm::SmallVector<llvm::StringRef>>
OffloadArchs;

private:
/// TranslateInputArgs - Create a new derived argument list from the input
Expand Down Expand Up @@ -535,11 +534,11 @@ class Driver {

/// Returns the set of bound architectures active for this offload kind.
/// If there are no bound architctures we return a set containing only the
/// empty string. The \p SuppressError option is used to suppress errors.
llvm::DenseSet<StringRef>
/// empty string.
llvm::SmallVector<StringRef>
getOffloadArchs(Compilation &C, const llvm::opt::DerivedArgList &Args,
Action::OffloadKind Kind, const ToolChain *TC,
bool SuppressError = false) const;
bool SpecificToolchain = true) const;

/// Check that the file referenced by Value exists. If it doesn't,
/// issue a diagnostic and return false.
Expand Down
132 changes: 68 additions & 64 deletions clang/lib/Driver/Driver.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -988,6 +988,8 @@ void Driver::CreateOffloadingDeviceToolChains(Compilation &C,
if (CudaInstallation.isValid())
CudaInstallation.WarnIfUnsupportedVersion();
C.addOffloadDeviceToolChain(&TC, Action::OFK_Cuda);
OffloadArchs[&TC] = getOffloadArchs(C, C.getArgs(), Action::OFK_Cuda, &TC,
/*SpecificToolchain=*/true);
} else if (IsHIP && !UseLLVMOffload) {
if (auto *OMPTargetArg =
C.getInputArgs().getLastArg(options::OPT_fopenmp_targets_EQ)) {
Expand All @@ -1004,6 +1006,12 @@ void Driver::CreateOffloadingDeviceToolChains(Compilation &C,
getOffloadToolChain(C.getInputArgs(), Action::OFK_HIP, *HIPTriple,
C.getDefaultToolChain().getTriple());
C.addOffloadDeviceToolChain(&TC, Action::OFK_HIP);

// TODO: Fix 'amdgcnspirv' handling with the new driver.
if (C.getInputArgs().hasFlag(options::OPT_offload_new_driver,
options::OPT_no_offload_new_driver, false))
OffloadArchs[&TC] = getOffloadArchs(C, C.getArgs(), Action::OFK_HIP, &TC,
/*SpecificToolchain=*/true);
}

if (IsCuda || IsHIP)
Expand Down Expand Up @@ -1069,40 +1077,43 @@ void Driver::CreateOffloadingDeviceToolChains(Compilation &C,
auto &TC = getOffloadToolChain(C.getInputArgs(), Action::OFK_OpenMP, TT,
C.getDefaultToolChain().getTriple());
C.addOffloadDeviceToolChain(&TC, Action::OFK_OpenMP);
OffloadArchs[&TC] =
getOffloadArchs(C, C.getArgs(), Action::OFK_OpenMP, &TC,
/*SpecificToolchain=*/true);
}
} else if (C.getInputArgs().hasArg(options::OPT_offload_arch_EQ) &&
((!IsHIP && !IsCuda) || UseLLVMOffload)) {
llvm::Triple AMDTriple("amdgcn-amd-amdhsa");
llvm::Triple NVPTXTriple("nvptx64-nvidia-cuda");

// Attempt to deduce the offloading triple from the set of architectures.
// We can only correctly deduce NVPTX / AMDGPU triples currently.
for (const llvm::Triple &TT : {AMDTriple, NVPTXTriple}) {
auto &TC = getOffloadToolChain(C.getInputArgs(), Action::OFK_OpenMP, TT,
C.getDefaultToolChain().getTriple());

llvm::DenseSet<StringRef> Archs =
getOffloadArchs(C, C.getArgs(), Action::OFK_OpenMP, &TC, true);
llvm::DenseSet<StringRef> ArchsForTarget;
for (StringRef Arch : Archs) {
for (StringRef A :
C.getInputArgs().getAllArgValues(options::OPT_offload_arch_EQ)) {
for (StringRef Arch : llvm::split(A, ",")) {
bool IsNVPTX = IsNVIDIAOffloadArch(
StringToOffloadArch(getProcessorFromTargetID(NVPTXTriple, Arch)));
bool IsAMDGPU = IsAMDOffloadArch(
StringToOffloadArch(getProcessorFromTargetID(AMDTriple, Arch)));
if (!IsNVPTX && !IsAMDGPU && !Arch.equals_insensitive("native")) {
if (!IsNVPTX && !IsAMDGPU && !Arch.empty() &&
!Arch.equals_insensitive("native")) {
Diag(clang::diag::err_drv_failed_to_deduce_target_from_arch)
<< Arch;
return;
}

if (TT.isNVPTX() && IsNVPTX)
ArchsForTarget.insert(Arch);
else if (TT.isAMDGPU() && IsAMDGPU)
ArchsForTarget.insert(Arch);
}
if (!ArchsForTarget.empty()) {
}

// Attempt to deduce the offloading triple from the set of architectures.
// We can only correctly deduce NVPTX / AMDGPU triples currently.
for (const llvm::Triple &TT : {AMDTriple, NVPTXTriple}) {
auto &TC = getOffloadToolChain(C.getInputArgs(), Action::OFK_OpenMP, TT,
C.getDefaultToolChain().getTriple());

llvm::SmallVector<StringRef> Archs =
getOffloadArchs(C, C.getArgs(), Action::OFK_OpenMP, &TC,
/*SpecificToolchain=*/false);
if (!Archs.empty()) {
C.addOffloadDeviceToolChain(&TC, Action::OFK_OpenMP);
KnownArchs[&TC] = ArchsForTarget;
OffloadArchs[&TC] = Archs;
}
}

Expand Down Expand Up @@ -1143,9 +1154,11 @@ void Driver::CreateOffloadingDeviceToolChains(Compilation &C,
// going to create will depend on both.
const ToolChain *HostTC = C.getSingleOffloadToolChain<Action::OFK_Host>();
for (const auto &TT : UniqueSYCLTriplesVec) {
auto SYCLTC = &getOffloadToolChain(C.getInputArgs(), Action::OFK_SYCL, TT,
HostTC->getTriple());
C.addOffloadDeviceToolChain(SYCLTC, Action::OFK_SYCL);
auto &TC = getOffloadToolChain(C.getInputArgs(), Action::OFK_SYCL, TT,
HostTC->getTriple());
C.addOffloadDeviceToolChain(&TC, Action::OFK_SYCL);
OffloadArchs[&TC] = getOffloadArchs(C, C.getArgs(), Action::OFK_SYCL, &TC,
/*SpecificToolchain=*/true);
}
}

Expand Down Expand Up @@ -4703,20 +4716,22 @@ static StringRef getCanonicalArchString(Compilation &C,
const llvm::opt::DerivedArgList &Args,
StringRef ArchStr,
const llvm::Triple &Triple,
bool SuppressError = false) {
bool SpecificToolchain) {
// Lookup the CUDA / HIP architecture string. Only report an error if we were
// expecting the triple to be only NVPTX / AMDGPU.
OffloadArch Arch =
StringToOffloadArch(getProcessorFromTargetID(Triple, ArchStr));
if (!SuppressError && Triple.isNVPTX() &&
if (Triple.isNVPTX() &&
(Arch == OffloadArch::UNKNOWN || !IsNVIDIAOffloadArch(Arch))) {
C.getDriver().Diag(clang::diag::err_drv_offload_bad_gpu_arch)
<< "CUDA" << ArchStr;
if (SpecificToolchain)
C.getDriver().Diag(clang::diag::err_drv_offload_bad_gpu_arch)
<< "CUDA" << ArchStr;
return StringRef();
} else if (!SuppressError && Triple.isAMDGPU() &&
} else if (Triple.isAMDGPU() &&
(Arch == OffloadArch::UNKNOWN || !IsAMDOffloadArch(Arch))) {
C.getDriver().Diag(clang::diag::err_drv_offload_bad_gpu_arch)
<< "HIP" << ArchStr;
if (SpecificToolchain)
C.getDriver().Diag(clang::diag::err_drv_offload_bad_gpu_arch)
<< "HIP" << ArchStr;
return StringRef();
}

Expand All @@ -4725,13 +4740,9 @@ static StringRef getCanonicalArchString(Compilation &C,

if (IsAMDOffloadArch(Arch)) {
llvm::StringMap<bool> Features;
auto HIPTriple = getHIPOffloadTargetTriple(C.getDriver(), C.getInputArgs());
if (!HIPTriple)
return StringRef();
auto Arch = parseTargetID(*HIPTriple, ArchStr, &Features);
std::optional<StringRef> Arch = parseTargetID(Triple, ArchStr, &Features);
if (!Arch) {
C.getDriver().Diag(clang::diag::err_drv_bad_target_id) << ArchStr;
C.setContainsError();
return StringRef();
}
return Args.MakeArgStringRef(getCanonicalTargetID(*Arch, Features));
Expand All @@ -4754,10 +4765,10 @@ getConflictOffloadArchCombination(const llvm::DenseSet<StringRef> &Archs,
return getConflictTargetIDCombination(ArchSet);
}

llvm::DenseSet<StringRef>
llvm::SmallVector<StringRef>
Driver::getOffloadArchs(Compilation &C, const llvm::opt::DerivedArgList &Args,
Action::OffloadKind Kind, const ToolChain *TC,
bool SuppressError) const {
bool SpecificToolchain) const {
if (!TC)
TC = &C.getDefaultToolChain();

Expand All @@ -4772,9 +4783,6 @@ Driver::getOffloadArchs(Compilation &C, const llvm::opt::DerivedArgList &Args,
: "--no-offload-arch");
}

if (KnownArchs.contains(TC))
return KnownArchs.lookup(TC);

llvm::DenseSet<StringRef> Archs;
for (auto *Arg : C.getArgsForToolChain(TC, /*BoundArch=*/"", Kind)) {
// Add or remove the seen architectures in order of appearance. If an
Expand All @@ -4784,7 +4792,7 @@ Driver::getOffloadArchs(Compilation &C, const llvm::opt::DerivedArgList &Args,
if (Arch == "native" || Arch.empty()) {
auto GPUsOrErr = TC->getSystemGPUArchs(Args);
if (!GPUsOrErr) {
if (SuppressError)
if (!SpecificToolchain)
llvm::consumeError(GPUsOrErr.takeError());
else
TC->getDriver().Diag(diag::err_drv_undetermined_gpu_arch)
Expand All @@ -4794,16 +4802,21 @@ Driver::getOffloadArchs(Compilation &C, const llvm::opt::DerivedArgList &Args,
}

for (auto ArchStr : *GPUsOrErr) {
Archs.insert(
StringRef CanonicalStr =
getCanonicalArchString(C, Args, Args.MakeArgString(ArchStr),
TC->getTriple(), SuppressError));
TC->getTriple(), SpecificToolchain);
if (!CanonicalStr.empty())
Archs.insert(CanonicalStr);
else if (SpecificToolchain)
return llvm::SmallVector<StringRef>();
}
} else {
StringRef ArchStr = getCanonicalArchString(
C, Args, Arch, TC->getTriple(), SuppressError);
if (ArchStr.empty())
return Archs;
Archs.insert(ArchStr);
StringRef CanonicalStr = getCanonicalArchString(
C, Args, Arch, TC->getTriple(), SpecificToolchain);
if (!CanonicalStr.empty())
Archs.insert(CanonicalStr);
else if (SpecificToolchain)
return llvm::SmallVector<StringRef>();
}
}
} else if (Arg->getOption().matches(options::OPT_no_offload_arch_EQ)) {
Expand All @@ -4812,27 +4825,20 @@ Driver::getOffloadArchs(Compilation &C, const llvm::opt::DerivedArgList &Args,
Archs.clear();
} else {
StringRef ArchStr = getCanonicalArchString(
C, Args, Arch, TC->getTriple(), SuppressError);
if (ArchStr.empty())
return Archs;
C, Args, Arch, TC->getTriple(), SpecificToolchain);
Archs.erase(ArchStr);
}
}
}
}

if (auto ConflictingArchs =
getConflictOffloadArchCombination(Archs, TC->getTriple())) {
getConflictOffloadArchCombination(Archs, TC->getTriple()))
C.getDriver().Diag(clang::diag::err_drv_bad_offload_arch_combo)
<< ConflictingArchs->first << ConflictingArchs->second;
C.setContainsError();
}

// Skip filling defaults if we're just querying what is availible.
if (SuppressError)
return Archs;

if (Archs.empty()) {
if (SpecificToolchain && Archs.empty()) {
if (Kind == Action::OFK_Cuda) {
Archs.insert(OffloadArchToString(OffloadArch::CudaDefault));
} else if (Kind == Action::OFK_HIP) {
Expand All @@ -4858,12 +4864,13 @@ Driver::getOffloadArchs(Compilation &C, const llvm::opt::DerivedArgList &Args,
}
}
}
} else {
Args.ClaimAllArgs(options::OPT_offload_arch_EQ);
Args.ClaimAllArgs(options::OPT_no_offload_arch_EQ);
}
Args.ClaimAllArgs(options::OPT_offload_arch_EQ);
Args.ClaimAllArgs(options::OPT_no_offload_arch_EQ);

return Archs;
SmallVector<StringRef> Sorted(Archs.begin(), Archs.end());
llvm::sort(Sorted);
return Sorted;
}

Action *Driver::BuildOffloadingActions(Compilation &C,
Expand Down Expand Up @@ -4927,10 +4934,7 @@ Action *Driver::BuildOffloadingActions(Compilation &C,
// Get the product of all bound architectures and toolchains.
SmallVector<std::pair<const ToolChain *, StringRef>> TCAndArchs;
for (const ToolChain *TC : ToolChains) {
llvm::DenseSet<StringRef> Arches = getOffloadArchs(C, Args, Kind, TC);
SmallVector<StringRef, 0> Sorted(Arches.begin(), Arches.end());
llvm::sort(Sorted);
for (StringRef Arch : Sorted) {
for (StringRef Arch : OffloadArchs.lookup(TC)) {
TCAndArchs.push_back(std::make_pair(TC, Arch));
DeviceActions.push_back(
C.MakeAction<InputAction>(*InputArg, InputType, CUID));
Expand Down
2 changes: 1 addition & 1 deletion clang/test/Driver/openmp-offload-gpu.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -307,7 +307,7 @@
// DRIVER_EMBEDDING: -fembed-offload-object={{.*}}.out

// RUN: %clang -### --target=x86_64-unknown-linux-gnu -ccc-print-bindings -fopenmp=libomp -fopenmp-targets=nvptx64-nvidia-cuda \
// RUN: --offload-host-only -nogpulib %s 2>&1 | FileCheck %s --check-prefix=CHECK-HOST-ONLY
// RUN: -Xopenmp-target=nvptx64-nvidia-cuda -march=sm_52 --offload-host-only -nogpulib %s 2>&1 | FileCheck %s --check-prefix=CHECK-HOST-ONLY
// CHECK-HOST-ONLY: "x86_64-unknown-linux-gnu" - "clang", inputs: ["[[INPUT:.*]]"], output: "[[OUTPUT:.*]]"
// CHECK-HOST-ONLY: "x86_64-unknown-linux-gnu" - "Offload::Linker", inputs: ["[[OUTPUT]]"], output: "a.out"

Expand Down