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[SYCL][Driver] Resolve device library locations by library name #23525

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7951c3c
[SYCL][Driver] Resolve device library locations by library name
mdtoguchi Oct 16, 2026
61b60db
Simplify comment
mdtoguchi Oct 19, 2026
29ced20
Add testing for updated libsycl-native lib checks
mdtoguchi Oct 19, 2026
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6 changes: 6 additions & 0 deletions clang/include/clang/Driver/SyclInstallationDetector.h
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Original file line number Diff line number Diff line change
Expand Up @@ -33,6 +33,12 @@ class SYCLInstallationDetector {

void getSYCLDeviceLibPath(
llvm::SmallVector<llvm::SmallString<128>, 4> &DeviceLibPaths) const;

/// \brief Search the SYCL device library locations for \p LibName.
/// \return The full path to the library if found, otherwise std::nullopt.
std::optional<llvm::SmallString<128>>
findSYCLDeviceLib(llvm::StringRef LibName) const;

void addSYCLIncludeArgs(const llvm::opt::ArgList &DriverArgs,
llvm::opt::ArgStringList &CC1Args) const;

Expand Down
77 changes: 29 additions & 48 deletions clang/lib/Driver/ToolChains/Clang.cpp
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Expand Up @@ -11556,18 +11556,11 @@ static void getNonTripleBasedSYCLPostLinkOpts(const ToolChain &TC,
if (TC.getTriple().isSPIROrSPIRV() && !TC.getTriple().isSPIRAOT()) {
SYCLInstallationDetector SYCLInstall(TC.getDriver(), TC.getTriple(),
TCArgs);
SmallVector<SmallString<128>, 4> DeviceLibLocCandidates;
SmallString<128> NativeBfloat16Name("libsycl-native-bfloat16.bc");
SYCLInstall.getSYCLDeviceLibPath(DeviceLibLocCandidates);
for (const auto &DeviceLibLoc : DeviceLibLocCandidates) {
SmallString<128> FullLibName(DeviceLibLoc);
llvm::sys::path::append(FullLibName, NativeBfloat16Name);
if (llvm::sys::fs::exists(FullLibName)) {
SmallString<128> SYCLDeviceLibDir("--device-lib-dir=");
SYCLDeviceLibDir += DeviceLibLoc.str();
addArgs(PostLinkArgs, TCArgs, {SYCLDeviceLibDir.str()});
break;
}
if (auto FullLibName =
SYCLInstall.findSYCLDeviceLib("libsycl-native-bfloat16.bc")) {
SmallString<128> SYCLDeviceLibDir("--device-lib-dir=");
SYCLDeviceLibDir += llvm::sys::path::parent_path(*FullLibName);
addArgs(PostLinkArgs, TCArgs, {SYCLDeviceLibDir.str()});
}
}
}
Expand Down Expand Up @@ -12256,74 +12249,62 @@ void LinkerWrapper::ConstructJob(Compilation &C, const JobAction &JA,
/*default=*/true))
CmdArgs.push_back("--no-sycl-rdc");

// -sycl-device-library-location=<dir> provides the location in which the
// SYCL device libraries can be found.
SmallString<128> DeviceLibDir(D.Dir);
llvm::sys::path::append(DeviceLibDir, "..", "lib");
// Check the library location candidates for the the libsycl-crt library
// and use that location. Base the location on relative to driver if this
// is not resolved.
SmallVector<SmallString<128>, 4> LibLocCandidates;
SYCLInstallationDetector SYCLInstallation(D, getToolChain().getTriple(),
Args);
SYCLInstallation.getSYCLDeviceLibPath(LibLocCandidates);
SmallString<128> LibName("libsycl-crt.bc");
for (const auto &LibLoc : LibLocCandidates) {
SmallString<128> FullLibName(LibLoc);
llvm::sys::path::append(FullLibName, LibName);
if (llvm::sys::fs::exists(FullLibName)) {
DeviceLibDir = LibLoc;
break;
}
}

// Device libraries for SYCL offloading are specified using
// --bitcode-library=<triple>=<path to bc file> for each library.
// The full path must be provided (not relative to
// -sycl-device-library-location).
//
// Note: SPIR/SPIRV device libraries are linked at compile time using
// -mlink-builtin-bitcode, so they are not passed here. Only non-SPIR
// targets (NVPTX, AMD) pass device libraries to clang-linker-wrapper.
// targets (NVPTX, AMD, NativeCPU) pass device libraries to
// clang-linker-wrapper.
SmallVector<std::string, 4> BCLibList;
bool HasNativeCPU = false;

auto ToolChainRange = C.getOffloadToolChains<Action::OFK_SYCL>();
for (const auto &[Kind, TC] :
llvm::make_range(ToolChainRange.first, ToolChainRange.second)) {
llvm::Triple TargetTriple = TC->getTriple();
SmallVector<ToolChain::BitCodeLibraryInfo, 8> SYCLDeviceLibs;
HasNativeCPU |= TargetTriple.isNativeCPU();
// SPIR or SPIR-V device libraries are compiled into the device compile
// step. Non-SPIR here means NVPTX/AMDGCN (CudaToolChain/AMDGPUToolChain).
// step. Non-SPIR here means NVPTX/AMDGCN (CudaToolChain/AMDGPUToolChain)
// or NativeCPU.
if (!TargetTriple.isSPIROrSPIRV()) {
const ToolChain *HostTC =
C.getSingleOffloadToolChain<Action::OFK_Host>();
std::unique_ptr<toolchains::SYCLToolChain> ScratchTC;
const toolchains::SYCLToolChain &SYCLTC =
toolchains::getSYCLToolChain(D, *TC, *HostTC, Args, ScratchTC);
SYCLDeviceLibs.append(SYCLTC.getDeviceLibNames(D, Args, TargetTriple));
}
for (const auto &AddLib : SYCLDeviceLibs) {
if (llvm::sys::path::extension(AddLib.Path) == ".bc") {
SmallString<256> LibPath(DeviceLibDir);
llvm::sys::path::append(LibPath, AddLib.Path);
BCLibList.push_back(
(Twine(TC->getTriple().str()) + "=" + LibPath).str());
continue;
}
// getDeviceLibs resolves the full path of each library and diagnoses
// any that are not found.
for (const auto &AddLib :
SYCLTC.getDeviceLibs(Args, /*BA=*/{}, Action::OFK_SYCL))
if (llvm::sys::path::extension(AddLib.Path) == ".bc")
BCLibList.push_back(
(Twine(TargetTriple.str()) + "=" + AddLib.Path).str());
}

if (TC->getTriple().isNVPTX())
if (TargetTriple.isNVPTX())
if (const char *LibSpirvFile = SYCLInstallation.findLibspirvPath(
TC->getTriple(), Args, *TC->getAuxTriple()))
TargetTriple, Args, *TC->getAuxTriple()))
BCLibList.push_back(
(Twine(TC->getTriple().str()) + "=" + LibSpirvFile).str());
(Twine(TargetTriple.str()) + "=" + LibSpirvFile).str());
}

if (BCLibList.size())
for (const std::string &Lib : BCLibList)
CmdArgs.push_back(
Args.MakeArgString(Twine("--bitcode-library=") + Lib));

// -sycl-device-library-location=<dir> provides the location of the
// native CPU/bfloat16 device libraries. Falls back to <Driver>/../lib.
SmallString<128> DeviceLibDir(D.Dir);
llvm::sys::path::append(DeviceLibDir, "..", "lib");
if (auto FullLibName = SYCLInstallation.findSYCLDeviceLib(
HasNativeCPU ? "libsycl-nativecpu_utils.bc"
: "libsycl-native-bfloat16.bc"))
DeviceLibDir = llvm::sys::path::parent_path(*FullLibName);
CmdArgs.push_back(Args.MakeArgString(
Twine("-sycl-device-library-location=") + DeviceLibDir));
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33 changes: 17 additions & 16 deletions clang/lib/Driver/ToolChains/SYCL.cpp
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Expand Up @@ -198,6 +198,19 @@ void SYCLInstallationDetector::getSYCLDeviceLibPath(
DeviceLibPaths.emplace_back(Path.str());
}

std::optional<SmallString<128>>

@iclsrc iclsrc Oct 19, 2026

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🔵 Suggestion: findSYCLDeviceLib now uses D.getVFS().exists(). The code it replaces used llvm::sys::fs::exists. This is arguably better, since it honors -ivfsoverlay. It is still a behavior change for all callers, so it is worth mentioning in the PR description. The header also uses std::optional and should include <optional> explicitly, to avoid relying on transitive includes.

SYCLInstallationDetector::findSYCLDeviceLib(StringRef LibName) const {
SmallVector<SmallString<128>, 4> DeviceLibPaths;
getSYCLDeviceLibPath(DeviceLibPaths);
for (const auto &LibPath : DeviceLibPaths) {
SmallString<128> FullLibName(LibPath);
llvm::sys::path::append(FullLibName, LibName);
if (D.getVFS().exists(FullLibName))
return FullLibName;
}
return std::nullopt;
}

void SYCLInstallationDetector::addSYCLIncludeArgs(
const ArgList &DriverArgs, ArgStringList &CC1Args) const {
if (DriverArgs.hasArg(options::OPT_nostdlibinc, options::OPT_nostdinc)) {
Expand Down Expand Up @@ -2075,31 +2088,19 @@ SYCLToolChain::getDeviceLibs(
const Action::OffloadKind DeviceOffloadingKind) const {
llvm::SmallVector<ToolChain::BitCodeLibraryInfo, 12> BCLibs;

SmallVector<SmallString<128>, 4> LibraryPaths;
SYCLInstallation.getSYCLDeviceLibPath(LibraryPaths);

// Formulate all of the device libraries needed for this compilation.
SmallVector<BitCodeLibraryInfo, 8> DeviceLibs =
getDeviceLibNames(getDriver(), DriverArgs, getTriple());

// Create full path names to each device library. If found, add to the list
// of device libraries that will be linked against.
for (const auto &DeviceLib : DeviceLibs) {
bool DeviceLibFound = false;
for (const auto &LibraryPath : LibraryPaths) {
SmallString<128> FullLibName(LibraryPath);
llvm::sys::path::append(FullLibName, DeviceLib.Path);
if (llvm::sys::fs::exists(FullLibName)) {
BitCodeLibraryInfo BitCodeLibrary(
{FullLibName, DeviceLib.ShouldInternalize});
BCLibs.emplace_back(BitCodeLibrary);
DeviceLibFound = true;
break;
}
}
// The device libraries are all known internal libraries. If any are not
// found, emit an error.
if (!DeviceLibFound)
if (auto FullLibName = SYCLInstallation.findSYCLDeviceLib(DeviceLib.Path))
BCLibs.emplace_back(
BitCodeLibraryInfo({*FullLibName, DeviceLib.ShouldInternalize}));
else
getDriver().Diag(diag::err_drv_no_sycl_device_lib) << DeviceLib.Path;
}
return BCLibs;
Expand Down
Empty file added clang/test/Driver/Inputs/SYCL/lib/dpcpp-7/sycl/libsycl-native-bfloat16.bc
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Empty file added clang/test/Driver/Inputs/SYCL/lib/dpcpp-7/sycl/libsycl-nativecpu_utils.bc
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Empty file.
57 changes: 51 additions & 6 deletions clang/test/Driver/sycl-bc-device-libraries.cpp
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@@ -1,13 +1,23 @@
/// Test that SYCL bitcode device libraries are properly separated for NVIDIA and AMD targets.
/// Also test the SYCL device library location passed to clang-linker-wrapper
/// (-sycl-device-library-location) and sycl-post-link (--device-lib-dir).

/// Check that a device library which cannot be found is diagnosed.

@srividya-sundaram srividya-sundaram Oct 19, 2026

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IIUC, the folder passed in -sycl-device-library-location= is now found by searching for libsycl-native-bfloat16.bc (or libsycl-nativecpu_utils.bc for NativeCPU) instead of libsycl-crt.bc.

In Inputs/SYCL, libsycl-crt.bc is in lib/dpcpp-7/sycl, but those two files are only in lib/.

So on a Linux host, this test's flag should change from .../bin/../lib/dpcpp-7/sycl to .../bin/../lib.
That's also the fallback value, so the test can't tell whether the search found the file or gave up.

Could you add dummy libsycl-native-bfloat16.bc and libsycl-nativecpu_utils.bc under Inputs/SYCL/lib/dpcpp-7/sycl, plus a RUN line with --target=x86_64-unknown-linux-gnu that checks the flag points there?

That would match the Linux install layout (lib/dpcpp-/sycl) and actually exercise the new search.

// RUN: not %clang -### -fsycl --offload-new-driver -ccc-install-dir %t.nonexistent/bin \
// RUN: -fno-sycl-libspirv -Wno-unsafe-libspirv-not-linked \
// RUN: -fsycl-targets=nvptx64-nvidia-cuda \
// RUN: --cuda-path=%S/Inputs/CUDA_102/usr/local/cuda \
// RUN: %s 2>&1 | FileCheck -check-prefix=CHECK-NVPTX-MISSING %s
// CHECK-NVPTX-MISSING: cannot find expected SYCL device library 'devicelib-nvptx64-nvidia-cuda.bc'

/// Check devicelib are linked for nvptx.
// RUN: %clang -### -fsycl --offload-new-driver \
// RUN: %clang -### -fsycl --offload-new-driver -ccc-install-dir %S/Inputs/SYCL/bin \
// RUN: -fno-sycl-libspirv -Wno-unsafe-libspirv-not-linked \
// RUN: -fsycl-targets=nvptx64-nvidia-cuda \
// RUN: --cuda-path=%S/Inputs/CUDA_102/usr/local/cuda \
// RUN: %s 2>&1 | FileCheck -check-prefix=CHECK-NVPTX-BC %s

// RUN: %clang_cl -### -fsycl --offload-new-driver \
// RUN: %clang_cl -### -fsycl --offload-new-driver -ccc-install-dir %S/Inputs/SYCL/bin \
// RUN: -fno-sycl-libspirv -Wno-unsafe-libspirv-not-linked \
// RUN: -fsycl-targets=nvptx64-nvidia-cuda \
// RUN: --cuda-path=%S/Inputs/CUDA_102/usr/local/cuda \
Expand All @@ -17,14 +27,14 @@
// CHECK-NVPTX-BC-SAME: "--bitcode-library=nvptx64-nvidia-cuda={{.*}}devicelib-nvptx64-nvidia-cuda.bc"

/// Check devicelib is linked for amdgcn.
// RUN: %clang -### -fsycl --offload-new-driver \
// RUN: %clang -### -fsycl --offload-new-driver -ccc-install-dir %S/Inputs/SYCL/bin \
// RUN: -fno-sycl-libspirv -Wno-unsafe-libspirv-not-linked \
// RUN: -fsycl-targets=amdgcn-amd-amdhsa \
// RUN: -Xsycl-target-backend=amdgcn-amd-amdhsa --offload-arch=gfx900 \
// RUN: --rocm-path=%S/Inputs/rocm \
// RUN: %s 2>&1 | FileCheck -check-prefix=CHECK-AMD-BC %s

// RUN: %clang_cl -### -fsycl --offload-new-driver \
// RUN: %clang_cl -### -fsycl --offload-new-driver -ccc-install-dir %S/Inputs/SYCL/bin \
// RUN: -fno-sycl-libspirv -Wno-unsafe-libspirv-not-linked \
// RUN: -fsycl-targets=amdgcn-amd-amdhsa \
// RUN: -Xsycl-target-backend=amdgcn-amd-amdhsa --offload-arch=gfx900 \
Expand All @@ -35,15 +45,15 @@
// CHECK-AMD-BC-SAME: "--bitcode-library=amdgcn-amd-amdhsa={{.*}}devicelib-amdgcn-amd-amdhsa.bc"

/// Check linking with multiple targets.
// RUN: %clang -### -fsycl --offload-new-driver \
// RUN: %clang -### -fsycl --offload-new-driver -ccc-install-dir %S/Inputs/SYCL/bin \
// RUN: -fno-sycl-libspirv -Wno-unsafe-libspirv-not-linked \
// RUN: -fsycl-targets=amdgcn-amd-amdhsa,nvptx64-nvidia-cuda \
// RUN: -Xsycl-target-backend=amdgcn-amd-amdhsa --offload-arch=gfx900 \
// RUN: --cuda-path=%S/Inputs/CUDA_102/usr/local/cuda \
// RUN: --rocm-path=%S/Inputs/rocm \
// RUN: %s 2>&1 | FileCheck -check-prefix=CHECK-MULTI-TARGET %s

// RUN: %clang_cl -### -fsycl --offload-new-driver \
// RUN: %clang_cl -### -fsycl --offload-new-driver -ccc-install-dir %S/Inputs/SYCL/bin \
// RUN: -fno-sycl-libspirv -Wno-unsafe-libspirv-not-linked \
// RUN: -fsycl-targets=amdgcn-amd-amdhsa,nvptx64-nvidia-cuda \
// RUN: -Xsycl-target-backend=amdgcn-amd-amdhsa --offload-arch=gfx900 \
Expand All @@ -53,3 +63,38 @@

// CHECK-MULTI-TARGET: clang-linker-wrapper
// CHECK-MULTI-TARGET-SAME: "--bitcode-library=amdgcn-amd-amdhsa={{.*}}devicelib-amdgcn-amd-amdhsa.bc" "--bitcode-library=nvptx64-nvidia-cuda={{.*}}devicelib-nvptx64-nvidia-cuda.bc"

/// The device library location is resolved from the library being consumed.
/// Inputs/SYCL matches the Linux install layout, with the libraries in
/// lib/dpcpp-7/sycl. Make sure that location is found, rather than the
/// <driver>/../lib fallback.
/// Non-NativeCPU targets use the location of libsycl-native-bfloat16.bc.
// RUN: %clang -### -fsycl --offload-new-driver --target=x86_64-unknown-linux-gnu \
// RUN: -ccc-install-dir %S/Inputs/SYCL/bin \
// RUN: -fsycl-targets=spir64 \
// RUN: %s 2>&1 | FileCheck -check-prefix=CHECK-LIB-LOC-BF16 %s
// CHECK-LIB-LOC-BF16: clang-linker-wrapper{{.*}} "-sycl-device-library-location={{.*}}SYCL{{[/\\]+}}bin{{[/\\]+}}..{{[/\\]+}}lib{{[/\\]+}}dpcpp-7{{[/\\]+}}sycl"

// RUN: %clang -### -fsycl --no-offload-new-driver --target=x86_64-unknown-linux-gnu \
// RUN: -ccc-install-dir %S/Inputs/SYCL/bin \
// RUN: -fsycl-targets=spir64 \
// RUN: %s 2>&1 | FileCheck -check-prefix=CHECK-LIB-LOC-BF16-POSTLINK %s
// CHECK-LIB-LOC-BF16-POSTLINK: sycl-post-link{{.*}} "--device-lib-dir={{.*}}SYCL{{[/\\]+}}bin{{[/\\]+}}..{{[/\\]+}}lib{{[/\\]+}}dpcpp-7{{[/\\]+}}sycl"

/// NativeCPU uses the location of libsycl-nativecpu_utils.bc.
// RUN: %clang -### -fsycl --offload-new-driver --target=x86_64-unknown-linux-gnu \
// RUN: -ccc-install-dir %S/Inputs/SYCL/bin \
// RUN: -fno-sycl-libspirv -Wno-unsafe-libspirv-not-linked \
// RUN: -fsycl-targets=native_cpu \
// RUN: %s 2>&1 | FileCheck -check-prefix=CHECK-LIB-LOC-NATIVECPU %s
// CHECK-LIB-LOC-NATIVECPU: clang-linker-wrapper
// CHECK-LIB-LOC-NATIVECPU-SAME: "--bitcode-library=native_cpu={{.*}}SYCL{{[/\\]+}}bin{{[/\\]+}}..{{[/\\]+}}lib{{[/\\]+}}dpcpp-7{{[/\\]+}}sycl{{[/\\]+}}libsycl-nativecpu_utils.bc"
// CHECK-LIB-LOC-NATIVECPU-SAME: "-sycl-device-library-location={{.*}}SYCL{{[/\\]+}}bin{{[/\\]+}}..{{[/\\]+}}lib{{[/\\]+}}dpcpp-7{{[/\\]+}}sycl"

/// When the library cannot be found, fall back to <driver>/../lib.
// RUN: %clang -### -fsycl --offload-new-driver --target=x86_64-unknown-linux-gnu \
// RUN: -ccc-install-dir %t.nonexistent/bin \
// RUN: --no-offloadlib -fno-sycl-instrument-device-code \
// RUN: -fsycl-targets=spir64 \
// RUN: %s 2>&1 | FileCheck -check-prefix=CHECK-LIB-LOC-FALLBACK %s
// CHECK-LIB-LOC-FALLBACK: clang-linker-wrapper{{.*}} "-sycl-device-library-location={{.*}}.nonexistent{{[/\\]+}}bin{{[/\\]+}}..{{[/\\]+}}lib"
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