[Openmp-commits] [openmp] [Libomptarget] Remove __tgt_image_info and use the ELF directly (PR #75720)

[Joseph Huber via Openmp-commits]

================
@@ -58,92 +59,58 @@ uint32_t getImplicitArgsSize(uint16_t Version) {
              : sizeof(AMDGPUImplicitArgsTy);
 }
 
-/// Parse a TargetID to get processor arch and feature map.
-/// Returns processor subarch.
-/// Returns TargetID features in \p FeatureMap argument.
-/// If the \p TargetID contains feature+, FeatureMap it to true.
-/// If the \p TargetID contains feature-, FeatureMap it to false.
-/// If the \p TargetID does not contain a feature (default), do not map it.
-StringRef parseTargetID(StringRef TargetID, StringMap<bool> &FeatureMap) {
-  if (TargetID.empty())
-    return llvm::StringRef();
-
-  auto ArchFeature = TargetID.split(":");
-  auto Arch = ArchFeature.first;
-  auto Features = ArchFeature.second;
-  if (Features.empty())
-    return Arch;
-
-  if (Features.contains("sramecc+")) {
-    FeatureMap.insert(std::pair<StringRef, bool>("sramecc", true));
-  } else if (Features.contains("sramecc-")) {
-    FeatureMap.insert(std::pair<StringRef, bool>("sramecc", false));
-  }
-  if (Features.contains("xnack+")) {
-    FeatureMap.insert(std::pair<StringRef, bool>("xnack", true));
-  } else if (Features.contains("xnack-")) {
-    FeatureMap.insert(std::pair<StringRef, bool>("xnack", false));
-  }
-
-  return Arch;
-}
-
-/// Check if an image is compatible with current system's environment.
-bool isImageCompatibleWithEnv(const __tgt_image_info *Info,
-                              StringRef EnvTargetID) {
-  llvm::StringRef ImageTargetID(Info->Arch);
-
-  // Compatible in case of exact match.
-  if (ImageTargetID == EnvTargetID) {
-    DP("Compatible: Exact match \t[Image: %s]\t:\t[Env: %s]\n",
-       ImageTargetID.data(), EnvTargetID.data());
-    return true;
-  }
-
-  // Incompatible if Archs mismatch.
-  StringMap<bool> ImgMap, EnvMap;
-  StringRef ImgArch = utils::parseTargetID(ImageTargetID, ImgMap);
-  StringRef EnvArch = utils::parseTargetID(EnvTargetID, EnvMap);
-
-  // Both EnvArch and ImgArch can't be empty here.
-  if (EnvArch.empty() || ImgArch.empty() || !ImgArch.contains(EnvArch)) {
-    DP("Incompatible: Processor mismatch \t[Image: %s]\t:\t[Env: %s]\n",
-       ImageTargetID.data(), EnvTargetID.data());
+/// Check if an image is compatible with current system's environment. The
+/// system environment is given as a 'target-id' which has the form:
+///
+/// <target-id> := <processor> ( ":" <target-feature> ( "+" | "-" ) )*
+///
+/// If a feature is not specific as '+' or '-' it is assumed to be in an 'any'
+/// and is compatible with either '+' or '-'. The HSA runtime returns this
+/// information using the target-id, while we use the ELF header to determine
+/// these features.
+inline bool isImageCompatibleWithEnv(StringRef ImageArch, uint32_t ImageFlags,
+                                     StringRef EnvTargetID) {
+  StringRef EnvArch = EnvTargetID.split(":").first;
+
+  // Trivial check if the base processors match.
+  if (EnvArch != ImageArch)
     return false;
-  }
 
-  // Incompatible if image has more features than the environment,
-  // irrespective of type or sign of features.
-  if (ImgMap.size() > EnvMap.size()) {
-    DP("Incompatible: Image has more features than the Environment \t[Image: "
-       "%s]\t:\t[Env: %s]\n",
-       ImageTargetID.data(), EnvTargetID.data());
-    return false;
+  // Check if the image is requesting xnack on or off.
----------------
jhuber6 wrote:

Does that net us anything? The information seems freely available in the ELF flags which is easier to retrieve than the AMDHSA metadata that's stored in a YAML form if memory serves. This way we don't need to parse anything and it's fast in the common case (No special flags set).

https://github.com/llvm/llvm-project/pull/75720