tra created this revision.
tra added a reviewer: jlebar.
tra added a subscriber: cfe-commits.
This makes clang's libdevice selection match that of NVCC as described in
http://docs.nvidia.com/cuda/libdevice-users-guide/basic-usage.html#version-selection
If required libdevice variant is not found, driver now fails with an error.
https://reviews.llvm.org/D23037
Files:
include/clang/Basic/DiagnosticDriverKinds.td
lib/Driver/ToolChains.cpp
test/Driver/cuda-detect.cu
Index: test/Driver/cuda-detect.cu
===================================================================
--- test/Driver/cuda-detect.cu
+++ test/Driver/cuda-detect.cu
@@ -29,12 +29,12 @@
// RUN: --cuda-path=%S/no-cuda-there %s 2>&1 \
// RUN: | FileCheck %s -check-prefix COMMON -check-prefix NOCUDAINC
-// Verify that no options related to bitcode linking are passes if
-// there's no bitcode file.
+// Verify that we get an error if there's no libdevice library to link with.
// RUN: %clang -### -v --target=i386-unknown-linux --cuda-gpu-arch=sm_30 \
// RUN: --cuda-path=%S/Inputs/CUDA/usr/local/cuda %s 2>&1 \
-// RUN: | FileCheck %s -check-prefix COMMON -check-prefix NOLIBDEVICE
-// .. or if we explicitly passed -nocudalib
+// RUN: | FileCheck %s -check-prefix COMMON -check-prefix MISSINGLIBDEVICE
+
+// Verify that -nocudalib prevents linking libdevice bitcode in.
// RUN: %clang -### -v --target=i386-unknown-linux --cuda-gpu-arch=sm_35 \
// RUN: -nocudalib --cuda-path=%S/Inputs/CUDA/usr/local/cuda %s 2>&1 \
// RUN: | FileCheck %s -check-prefix COMMON -check-prefix NOLIBDEVICE
@@ -48,6 +48,8 @@
// CHECK: Found CUDA installation: {{.*}}/Inputs/CUDA/usr/local/cuda
// NOCUDA-NOT: Found CUDA installation:
+// MISSINGLIBDEVICE: error: cannot find libdevice for sm_30.
+
// COMMON: "-triple" "nvptx-nvidia-cuda"
// COMMON-SAME: "-fcuda-is-device"
// LIBDEVICE-SAME: "-mlink-cuda-bitcode"
Index: lib/Driver/ToolChains.cpp
===================================================================
--- lib/Driver/ToolChains.cpp
+++ lib/Driver/ToolChains.cpp
@@ -1791,22 +1791,32 @@
LibDeviceName.size(), FileName.find('.', LibDeviceName.size()));
LibDeviceMap[GpuArch] = FilePath.str();
// Insert map entries for specifc devices with this compute capability.
+ // NVCC's choice of libdevice library version is rather peculiar:
+ // http://docs.nvidia.com/cuda/libdevice-users-guide/basic-usage.html#version-selection
+ // TODO: this will need to be updated once CUDA-8 is released.
if (GpuArch == "compute_20") {
LibDeviceMap["sm_20"] = FilePath;
LibDeviceMap["sm_21"] = FilePath;
+ LibDeviceMap["sm_32"] = FilePath;
} else if (GpuArch == "compute_30") {
LibDeviceMap["sm_30"] = FilePath;
- LibDeviceMap["sm_32"] = FilePath;
- } else if (GpuArch == "compute_35") {
- LibDeviceMap["sm_35"] = FilePath;
- LibDeviceMap["sm_37"] = FilePath;
- } else if (GpuArch == "compute_50") {
+ // compute_30 is the fallback libdevice variant for sm_30+,
+ // unless CUDA specifies different version for specific GPU
+ // arch.
LibDeviceMap["sm_50"] = FilePath;
LibDeviceMap["sm_52"] = FilePath;
LibDeviceMap["sm_53"] = FilePath;
+ // sm_6? are currently all aliases for sm_53 in LLVM and
+ // should use compute_30.
LibDeviceMap["sm_60"] = FilePath;
LibDeviceMap["sm_61"] = FilePath;
LibDeviceMap["sm_62"] = FilePath;
+ } else if (GpuArch == "compute_35") {
+ LibDeviceMap["sm_35"] = FilePath;
+ LibDeviceMap["sm_37"] = FilePath;
+ } else if (GpuArch == "compute_50") {
+ // NVCC does not use compute_50 libdevice at all at the moment.
+ // The version that's shipped with CUDA-7.5 is a copy of compute_30.
}
}
@@ -4759,27 +4769,31 @@
if (DriverArgs.hasArg(options::OPT_nocudalib))
return;
- std::string LibDeviceFile = CudaInstallation.getLibDeviceFile(
- DriverArgs.getLastArgValue(options::OPT_march_EQ));
- if (!LibDeviceFile.empty()) {
- CC1Args.push_back("-mlink-cuda-bitcode");
- CC1Args.push_back(DriverArgs.MakeArgString(LibDeviceFile));
+ StringRef GpuArch =
+ DriverArgs.getLastArgValue(options::OPT_march_EQ, "sm_20");
+ std::string LibDeviceFile = CudaInstallation.getLibDeviceFile(GpuArch);
- // Libdevice in CUDA-7.0 requires PTX version that's more recent
- // than LLVM defaults to. Use PTX4.2 which is the PTX version that
- // came with CUDA-7.0.
- CC1Args.push_back("-target-feature");
- CC1Args.push_back("+ptx42");
+ if (LibDeviceFile.empty()) {
+ getDriver().Diag(diag::err_drv_no_cuda_libdevice) << GpuArch;
+ return;
}
+
+ CC1Args.push_back("-mlink-cuda-bitcode");
+ CC1Args.push_back(DriverArgs.MakeArgString(LibDeviceFile));
+
+ // Libdevice in CUDA-7.0 requires PTX version that's more recent
+ // than LLVM defaults to. Use PTX4.2 which is the PTX version that
+ // came with CUDA-7.0.
+ CC1Args.push_back("-target-feature");
+ CC1Args.push_back("+ptx42");
}
void CudaToolChain::AddCudaIncludeArgs(const ArgList &DriverArgs,
ArgStringList &CC1Args) const {
// Check our CUDA version if we're going to include the CUDA headers.
if (!DriverArgs.hasArg(options::OPT_nocudainc) &&
!DriverArgs.hasArg(options::OPT_no_cuda_version_check)) {
- StringRef Arch = DriverArgs.getLastArgValue(options::OPT_march_EQ);
- assert(!Arch.empty() && "Must have an explicit GPU arch.");
+ StringRef Arch = DriverArgs.getLastArgValue(options::OPT_march_EQ, "sm_20");
CudaInstallation.CheckCudaVersionSupportsArch(StringToCudaArch(Arch));
}
Linux::AddCudaIncludeArgs(DriverArgs, CC1Args);
Index: include/clang/Basic/DiagnosticDriverKinds.td
===================================================================
--- include/clang/Basic/DiagnosticDriverKinds.td
+++ include/clang/Basic/DiagnosticDriverKinds.td
@@ -26,6 +26,9 @@
def err_drv_no_cuda_installation : Error<
"cannot find CUDA installation. Provide its path via --cuda-path, or pass "
"-nocudainc to build without CUDA includes.">;
+def err_drv_no_cuda_libdevice : Error<
+ "cannot find libdevice for %0. Provide path to different CUDA installation "
+ "via --cuda-path, or pass -nocudalib to build without linking with libdevice.">;
def err_drv_cuda_version_too_low : Error<
"GPU arch %1 requires CUDA version at least %3, but installation at %0 is %2. "
"Use --cuda-path to specify a different CUDA install, or pass "
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