[clang] [flang] [Flang][AMDGPU] Add rocm-path flag (PR #88190)

[Dominik Adamski via cfe-commits]

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@@ -345,7 +345,13 @@ void Flang::AddAMDGPUTargetArgs(const ArgList &Args,
 
   // Check ROCm path if specified
   const ToolChain &TC = getToolChain();
-  TC.getDeviceLibs(Args);
+  std::string HIPVersion;
+  llvm::raw_string_ostream HIPInfo(HIPVersion);
+  TC.printVerboseInfo(HIPInfo);
+  llvm::StringRef HIPInfoStrRef(HIPInfo.str());
+  if (!HIPInfoStrRef.contains("Found HIP installation") &&
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DominikAdamski wrote:

Clang reports an error if `--rocm-path` points to an invalid directory. I need to do a similar check for Flang.

The ROCm toolchain checks rocm-path within function `RocmInstallationDetector::checkCommonBitcodeLibs`. This function is called inside `ROCMToolChain::addClangTargetOptions` or `ROCMToolChain::getCommonDeviceLibNames`. `ROCMToolChain::getCommonDeviceLibNames` is called by `AMDGPUOpenMPToolChain::getDeviceLibs`. I decided not to call  `ROCMToolChain::addClangTargetOptions` because Flang does not support all Clang options. That's why I initially decided to call `AMDGPUOpenMPToolChain::getDeviceLibs` to check the ROCm path. The second (current) approach is a workaround to emit an error if rocm-path is specified incorrectly.

https://github.com/llvm/llvm-project/pull/88190