[HIP] Fix HIP path detection

[yaxunl]

Summary

Fix two issues:

1. --hip-path should not do rigorous checking, i.e. if .hipVersion exists it will use it, otherwise it will not error out but assumes the default HIP version. This is to be consistent with --rocm-path behavior.

2. when HIP_PATH is empty, it should be ignored. This is to be consistent with ROCM_PATH behavior.

clang/lib/Driver/ToolChains/AMDGPU.cpp

for (const auto &Candidate : ROCmDirs) {
     if (HasDeviceLibrary)
       return;
   }
 }
 
 void RocmInstallationDetector::detectHIPRuntime() {
   SmallVector<Candidate, 4> HIPSearchDirs;
   if (!HIPPathArg.empty())
-    HIPSearchDirs.emplace_back(HIPPathArg.str(), /*StrictChecking=*/true);
+    HIPSearchDirs.emplace_back(HIPPathArg.str());
   else if (std::optional<std::string> HIPPathEnv =
                llvm::sys::Process::GetEnv("HIP_PATH")) {
     if (!HIPPathEnv->empty())
       HIPSearchDirs.emplace_back(std::move(*HIPPathEnv));
-  } else
+  }
+  if (HIPSearchDirs.empty())
     HIPSearchDirs.append(getInstallationPathCandidates());
   auto &FS = D.getVFS();
 
   for (const auto &Candidate : HIPSearchDirs) {
     InstallPath = Candidate.Path;
     if (InstallPath.empty() || !FS.exists(InstallPath))
       continue;
     // HIP runtime built by SPACK is installed to

clang/test/Driver/hip-version.hip

 // REQUIRES: x86-registered-target
 // REQUIRES: amdgpu-registered-target
 // UNSUPPORTED: target={{.*}}-aix{{.*}}
 
 // RUN: %clang -v --rocm-path=%S/Inputs/rocm 2>&1 \
 // RUN:   | FileCheck -check-prefixes=FOUND %s
 
+// RUN: env ROCM_PATH=%S/Inputs/rocm %clang -v 2>&1 \
+// RUN:   | FileCheck -check-prefixes=FOUND %s
+
 // RUN: %clang -v --rocm-path=%S/Inputs/rocm 2>&1 \
 // RUN:   --target=amdgcn-amd-amdhsa \
 // RUN:   | FileCheck -check-prefixes=FOUND %s
 
+// RUN: %clang -v --hip-path=%S/Inputs/rocm 2>&1 \
+// RUN:   | FileCheck -check-prefixes=FOUND %s
+
+// RUN: env HIP_PATH=%S/Inputs/rocm %clang -v 2>&1 \
+// RUN:   | FileCheck -check-prefixes=FOUND %s
+
 // RUN: rm -rf %t/Inputs
 // RUN: mkdir -p %t/Inputs
 // RUN: cp -r %S/Inputs/rocm %t/Inputs
 // RUN: mkdir -p %t/Inputs/rocm/share/hip
 // RUN: mv %t/Inputs/rocm/bin/.hipVersion %t/Inputs/rocm/share/hip/version
 // RUN: %clang -v --rocm-path=%t/Inputs/rocm 2>&1 \
 // RUN:   | FileCheck -check-prefixes=FOUND %s
 
 // FOUND: Found HIP installation: {{.*Inputs.*rocm}}, version 3.6.20214-a2917cd
 
 // When --rocm-path is set and .hipVersion is not found, use default version
 
 // RUN: %clang -v --rocm-path=%S 2>&1 \
 // RUN:   | FileCheck -check-prefixes=DEFAULT %s
 
+// When --hip-path is set and .hipVersion is not found, use default version
+
+// RUN: %clang -v --hip-path=%S 2>&1 \
+// RUN:   | FileCheck -check-prefixes=DEFAULT %s
+
 // RUN: %clang -v --rocm-path=%S 2>&1 \
 // RUN:   --target=amdgcn-amd-amdhsa \
 // RUN:   | FileCheck -check-prefixes=DEFAULT %s
 
 // DEFAULT: Found HIP installation: {{.*Driver}}, version 3.5.
 
 // RUN: %clang -v --rocm-path=%S --hip-version=3.7.0 2>&1 \
 // RUN:   | FileCheck -check-prefixes=SPECIFIED %s

clang/test/Driver/rocm-detect.hip

 
 // Test interaction between environment variables HIP_PATH and ROCM_PATH.
 // Device libs are found under ROCM_PATH. HIP include files and HIP runtime library
 // are found under HIP_PATH.
 
 // RUN: rm -rf %t/myhip
 // RUN: mkdir -p %t/myhip
 // RUN: cp -r %S/Inputs/rocm/bin %t/myhip
+
+// Test HIP_PATH overrides ROCM_PATH.
 // RUN: env ROCM_PATH=%S/Inputs/rocm HIP_PATH=%t/myhip \
 // RUN:   %clang -### -target x86_64-linux-gnu --offload-arch=gfx1010 --hip-link \
 // RUN:   --print-rocm-search-dirs %s 2>&1 \
 // RUN:   | FileCheck -check-prefixes=ROCM-ENV,HIP-PATH %s
 
+// Test --hip-path overrides ROCM_PATH.
+// RUN: env ROCM_PATH=%S/Inputs/rocm \
+// RUN:   %clang -### -target x86_64-linux-gnu --offload-arch=gfx1010 --hip-link \
+// RUN:   --hip-path=%t/myhip \
+// RUN:   --print-rocm-search-dirs %s 2>&1 \
+// RUN:   | FileCheck -check-prefixes=ROCM-ENV,HIP-PATH %s
+
+// Test --hip-path overrides --rocm-path.
+// RUN: %clang -### -target x86_64-linux-gnu --offload-arch=gfx1010 --hip-link \
+// RUN:   --hip-path=%t/myhip --rocm-path=%S/Inputs/rocm \
+// RUN:   --print-rocm-search-dirs %s 2>&1 \
+// RUN:   | FileCheck -check-prefixes=ROCM-ENV,HIP-PATH %s
+
+// Test HIP_PATH overrides --rocm-path.
+// RUN: env HIP_PATH=%t/myhip %clang -### -target x86_64-linux-gnu --offload-arch=gfx1010 --hip-link \
+// RUN:   --rocm-path=%S/Inputs/rocm \
+// RUN:   --print-rocm-search-dirs %s 2>&1 \
+// RUN:   | FileCheck -check-prefixes=ROCM-ENV,HIP-PATH %s
+
+// Test empty HIP_PATH does not override --rocm-path.
+// RUN: env HIP_PATH= \
+// RUN:   %clang -### -target x86_64-linux-gnu --offload-arch=gfx1010 --hip-link \
+// RUN:   --rocm-path=%S/Inputs/rocm --print-rocm-search-dirs %s 2>&1 \
+// RUN:   | FileCheck -check-prefixes=ROCM-PATH %s
+
 // Test --hip-path option overrides environment variable HIP_PATH.
 
 // RUN: rm -rf %t/myhip
 // RUN: rm -rf %t/myhip_nouse
 // RUN: mkdir -p %t/myhip
 // RUN: mkdir -p %t/myhip_nouse
 // RUN: cp -r %S/Inputs/rocm/bin %t/myhip
 // RUN: cp -r %S/Inputs/rocm/bin %t/myhip_nouse

 // COMMON: "-triple" "amdgcn-amd-amdhsa"
 
 // ROCM-ENV: ROCm installation search path: [[ROCM_PATH:.*/Inputs/rocm]]
 
 // HIP-PATH: "-mlink-builtin-bitcode" "[[ROCM_PATH]]/amdgcn/bitcode/oclc_isa_version_1010.bc"
 // HIP-PATH: "-idirafter" "[[HIP_PATH:.*/myhip]]/include"
 // HIP-PATH: "-L[[HIP_PATH]]/lib" "-lamdhip64"
 
+// ROCM-PATH: ROCm installation search path: [[ROCM_PATH:.*/Inputs/rocm]]
+// ROCM-PATH: "-mlink-builtin-bitcode" "[[ROCM_PATH]]/amdgcn/bitcode/oclc_isa_version_1010.bc"
+// ROCM-PATH: "-idirafter" "[[ROCM_PATH]]/include"
+// ROCM-PATH: "-L[[ROCM_PATH]]/lib" "-lamdhip64"
+
 // ROCM-REL: ROCm installation search path: {{.*}}/opt/rocm
 // ROCM-REL: ROCm installation search path: {{.*}}/opt/rocm-3.10.0
 
 // SPACK: InstalledDir: [[DIR:.*]]/llvm-amdgpu-4.0.0-ieagcs7inf7runpyfvepqkurasoglq4z/bin
 // SPACK: ROCm installation search path (Spack 4.0.0): [[DIR]]
 // SPACK: ROCm installation search path: [[CLANG:.*]]
 // SPACK: ROCm installation search path: [[DIR]]/llvm-amdgpu-4.0.0-ieagcs7inf7runpyfvepqkurasoglq4z
 // SPACK: ROCm installation search path: [[DIR]]/llvm-amdgpu-4.0.0-ieagcs7inf7runpyfvepqkurasoglq4z/lib/clang