[CUDA] Detect and link with CUDA's libdevice bitcode library.
- added detection of libdevice bitcode file and API to find one appropriate for the GPU we're compiling for.
- pass additional cc1 options for linking with detected libdevice bitcode
- added -nocudalib to prevent automatic linking with libdevice
- added test cases to verify new functionality
Differential Revision: http://reviews.llvm.org/D14556
llvm-svn: 253387
diff --git a/clang/lib/Driver/ToolChains.cpp b/clang/lib/Driver/ToolChains.cpp
index 3450473..531e790 100644
--- a/clang/lib/Driver/ToolChains.cpp
+++ b/clang/lib/Driver/ToolChains.cpp
@@ -1647,6 +1647,31 @@
D.getVFS().exists(CudaLibDevicePath)))
continue;
+ std::error_code EC;
+ for (llvm::sys::fs::directory_iterator LI(CudaLibDevicePath, EC), LE;
+ !EC && LI != LE; LI = LI.increment(EC)) {
+ StringRef FilePath = LI->path();
+ StringRef FileName = llvm::sys::path::filename(FilePath);
+ // Process all bitcode filenames that look like libdevice.compute_XX.YY.bc
+ const StringRef LibDeviceName = "libdevice.";
+ if (!(FileName.startswith(LibDeviceName) && FileName.endswith(".bc")))
+ continue;
+ StringRef GpuArch = FileName.slice(
+ LibDeviceName.size(), FileName.find('.', LibDeviceName.size()));
+ CudaLibDeviceMap[GpuArch] = FilePath.str();
+ // Insert map entries for specifc devices with this compute capability.
+ if (GpuArch == "compute_20") {
+ CudaLibDeviceMap["sm_20"] = FilePath;
+ CudaLibDeviceMap["sm_21"] = FilePath;
+ } else if (GpuArch == "compute_30") {
+ CudaLibDeviceMap["sm_30"] = FilePath;
+ CudaLibDeviceMap["sm_32"] = FilePath;
+ } else if (GpuArch == "compute_35") {
+ CudaLibDeviceMap["sm_35"] = FilePath;
+ CudaLibDeviceMap["sm_37"] = FilePath;
+ }
+ }
+
IsValid = true;
break;
}
@@ -4195,6 +4220,22 @@
llvm::opt::ArgStringList &CC1Args) const {
Linux::addClangTargetOptions(DriverArgs, CC1Args);
CC1Args.push_back("-fcuda-is-device");
+
+ 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));
+
+ // 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");
+ }
}
llvm::opt::DerivedArgList *