[HIP] Fix environment variable HIP_DEVICE_LIB_PATH

[yaxunl]

Summary

Currently device lib path set by environment variable HIP_DEVICE_LIB_PATH
does not work due to extra "-L" added to each entry.

This patch fixes that by allowing argument name to be empty in addDirectoryList.

[tra]

If user sets HIP_DEVICE_LIB_PATH, this line in HIP.cpp
addDirectoryList(DriverArgs, LibraryPaths, "-L", "HIP_DEVICE_LIB_PATH");
adds -L<value of env var HIP_DEVICE_LIB_PATH> to LibraryPaths. -L is
needed since otherwise addDirectoryList will insert an extra empty string.
However, the -L must be stripped before checking for existence in addBCLib.

The fact that "-I" and "-L" are prepended to the paths is an implementation detail.
IMO it would be better to fix addDirectoryList() so it can deal with empty prefixes, and document it in the CommonArgs.h.

[yaxunl]

Revised by Artem's comments.

[thakis]

This breaks check-clang on Windows: http://45.33.8.238/win/6843/step_7.txt

You probably want "env FOO=bar" instead of "FOO=bar" in the test file.

[yaxunl]

In D73299#1845162, @thakis wrote:

This breaks check-clang on Windows: http://45.33.8.238/win/6843/step_7.txt

You probably want "env FOO=bar" instead of "FOO=bar" in the test file.

Fixed. Thanks.

clang/lib/Driver/ToolChains/CommonArgs.h

 bool isObjCAutoRefCount(const llvm::opt::ArgList &Args);
 
 unsigned getLTOParallelism(const llvm::opt::ArgList &Args, const Driver &D);
 
 bool areOptimizationsEnabled(const llvm::opt::ArgList &Args);
 
 bool isUseSeparateSections(const llvm::Triple &Triple);
 
+/// \p EnvVar is split by system delimiter for environment variables.
+/// If \p ArgName is "-I", "-L", or an empty string, each entry from \p EnvVar
+/// is prefixed by \p ArgName then added to \p Args. Otherwise, for each
+/// entry of \p EnvVar, \p ArgName is added to \p Args first, then the entry
+/// itself is added.
 void addDirectoryList(const llvm::opt::ArgList &Args,
                       llvm::opt::ArgStringList &CmdArgs, const char *ArgName,
                       const char *EnvVar);
 
 void AddTargetFeature(const llvm::opt::ArgList &Args,
                       std::vector<StringRef> &Features,
                       llvm::opt::OptSpecifier OnOpt,
                       llvm::opt::OptSpecifier OffOpt, StringRef FeatureName);

clang/lib/Driver/ToolChains/CommonArgs.cpp

void tools::addDirectoryList(const ArgList &Args, ArgStringList &CmdArgs,
                              const char *ArgName, const char *EnvVar) {
   const char *DirList = ::getenv(EnvVar);
   bool CombinedArg = false;
 
   if (!DirList)
     return; // Nothing to do.
 
   StringRef Name(ArgName);
-  if (Name.equals("-I") || Name.equals("-L"))
+  if (Name.equals("-I") || Name.equals("-L") || Name.empty())
     CombinedArg = true;
 
   StringRef Dirs(DirList);
   if (Dirs.empty()) // Empty string should not add '.'.
     return;
 
   StringRef::size_type Delim;
   while ((Delim = Dirs.find(llvm::sys::EnvPathSeparator)) != StringRef::npos) {

clang/lib/Driver/ToolChains/HIP.cpp

if (DriverArgs.hasArg(options::OPT_nogpulib))
     return;
   ArgStringList LibraryPaths;
 
   // Find in --hip-device-lib-path and HIP_LIBRARY_PATH.
   for (auto Path :
        DriverArgs.getAllArgValues(options::OPT_hip_device_lib_path_EQ))
     LibraryPaths.push_back(DriverArgs.MakeArgString(Path));
 
-  addDirectoryList(DriverArgs, LibraryPaths, "-L", "HIP_DEVICE_LIB_PATH");
+  addDirectoryList(DriverArgs, LibraryPaths, "", "HIP_DEVICE_LIB_PATH");
 
   llvm::SmallVector<std::string, 10> BCLibs;
 
   // Add bitcode library in --hip-device-lib.
   for (auto Lib : DriverArgs.getAllArgValues(options::OPT_hip_device_lib_EQ)) {
     BCLibs.push_back(DriverArgs.MakeArgString(Lib));
   }
 

clang/test/Driver/hip-device-libs.hip

 // Test flush-denormals-to-zero disabled uses oclc_daz_opt_off
 
 // RUN: %clang -### -target x86_64-linux-gnu \
 // RUN:   -x hip --cuda-gpu-arch=gfx900 \
 // RUN:   --hip-device-lib-path=%S/Inputs/hip_dev_lib \
 // RUN:   %S/Inputs/hip_multiple_inputs/b.hip \
 // RUN: 2>&1 | FileCheck %s --check-prefixes=COM,NOFLUSHD
 
+// Test environment variable HIP_DEVICE_LIB_PATH
+
+// RUN: HIP_DEVICE_LIB_PATH=%S/Inputs/hip_dev_lib \
+// RUN:   %clang -### -target x86_64-linux-gnu \
+// RUN:   -x hip --cuda-gpu-arch=gfx900 \
+// RUN:   %S/Inputs/hip_multiple_inputs/b.hip \
+// RUN: 2>&1 | FileCheck %s --check-prefixes=COM
 
 // COM: {{"[^"]*clang[^"]*"}}
 // COM-SAME: "-mlink-builtin-bitcode" "{{.*}}hip.amdgcn.bc"
 // COM-SAME: "-mlink-builtin-bitcode" "{{.*}}ocml.amdgcn.bc"
 // COM-SAME: "-mlink-builtin-bitcode" "{{.*}}ockl.amdgcn.bc"
 // FLUSHD-SAME: "-mlink-builtin-bitcode" "{{.*}}oclc_daz_opt_on.amdgcn.bc"
 // NOFLUSHD-SAME: "-mlink-builtin-bitcode" "{{.*}}oclc_daz_opt_off.amdgcn.bc"