[llvm] [SPIRV] Change how to detect OpenCL/Vulkan Env and update tests accordingly. (PR #129689)

[Steven Perron via llvm-commits]

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@@ -267,14 +267,37 @@ static SPIRVType *getArgSPIRVType(const Function &F, unsigned ArgIdx,
 
 static SPIRV::ExecutionModel::ExecutionModel
 getExecutionModel(const SPIRVSubtarget &STI, const Function &F) {
-  if (STI.isOpenCLEnv())
+  if (STI.isKernel())
     return SPIRV::ExecutionModel::Kernel;
 
+  if (STI.isShader()) {
+    auto attribute = F.getFnAttribute("hlsl.shader");
+    if (!attribute.isValid()) {
+      report_fatal_error(
+          "This entry point lacks mandatory hlsl.shader attribute.");
+    }
+
+    const auto value = attribute.getValueAsString();
+    if (value == "compute")
+      return SPIRV::ExecutionModel::GLCompute;
+
+    report_fatal_error(
+        "This HLSL entry point is not supported by this backend.");
+  }
+
+  assert(STI.getEnv() == SPIRVSubtarget::Unknown);
+  // "hlsl.shader" attribute is mandatory for Vulkan, so we can set Env to
+  // Shader whenever we find it, and to Kernel otherwise.
+
+  // We will now change the Env based on the attribute, so we need to strip
+  // `const` out of the ref to STI.
+  SPIRVSubtarget *NonConstSTI = const_cast<SPIRVSubtarget *>(&STI);
   auto attribute = F.getFnAttribute("hlsl.shader");
   if (!attribute.isValid()) {
-    report_fatal_error(
-        "This entry point lacks mandatory hlsl.shader attribute.");
+    NonConstSTI->setEnv(SPIRVSubtarget::Kernel);
+    return SPIRV::ExecutionModel::Kernel;
   }
+  NonConstSTI->setEnv(SPIRVSubtarget::Shader);
----------------
s-perron wrote:

I just notice this causes the result of isShader to change part way through the compilation. This can cause inconsistent results. I've opened issue https://github.com/llvm/llvm-project/issues/171898 to follow up on this.

https://github.com/llvm/llvm-project/pull/129689