[Clang][HLSL] Add environment parameter to availability attribute (#89809)

Add `environment` parameter to Clang availability attribute. The allowed
values for this parameter are a subset of values allowed in the
`llvm::Triple` environment component. If the `environment` parameters is
present, the declared availability attribute applies only to targets
with the same platform and environment.

This new parameter will be initially used for annotating HLSL functions
for the `shadermodel` platform because in HLSL built-in function
availability can depend not just on the shader model version (mapped to
`llvm::Triple::OSType`) but also on the target shader stage (mapped to
`llvm::Triple::EnvironmentType`). See example in #89802 and
microsoft/hlsl-specs#204 for more details.

The environment parameter is currently supported only for HLSL.

Fixes #89802

1 files changed, 22 insertions, 6 deletions

diff --git a/clang/lib/AST/DeclBase.cpp b/clang/lib/AST/DeclBase.cpp
index 03e1055..65d5eeb 100644
--- a/clang/lib/AST/DeclBase.cpp
+++ b/clang/lib/AST/DeclBase.cpp
@@ -666,12 +666,28 @@ static AvailabilityResult CheckAvailability(ASTContext &Context,
   // Make sure that this declaration has already been introduced.
   if (!A->getIntroduced().empty() &&
       EnclosingVersion < A->getIntroduced()) {
-    if (Message) {
-      Message->clear();
-      llvm::raw_string_ostream Out(*Message);
-      VersionTuple VTI(A->getIntroduced());
-      Out << "introduced in " << PrettyPlatformName << ' '
-          << VTI << HintMessage;
+    IdentifierInfo *IIEnv = A->getEnvironment();
+    StringRef TargetEnv =
+        Context.getTargetInfo().getTriple().getEnvironmentName();
+    StringRef EnvName = AvailabilityAttr::getPrettyEnviromentName(TargetEnv);
+    // Matching environment or no environment on attribute
+    if (!IIEnv || (!TargetEnv.empty() && IIEnv->getName() == TargetEnv)) {
+      if (Message) {
+        Message->clear();
+        llvm::raw_string_ostream Out(*Message);
+        VersionTuple VTI(A->getIntroduced());
+        Out << "introduced in " << PrettyPlatformName << " " << VTI << " "
+            << EnvName << HintMessage;
+      }
+    }
+    // Non-matching environment or no environment on target
+    else {
+      if (Message) {
+        Message->clear();
+        llvm::raw_string_ostream Out(*Message);
+        Out << "not available on " << PrettyPlatformName << " " << EnvName
+            << HintMessage;
+      }
     }
 
     return A->getStrict() ? AR_Unavailable : AR_NotYetIntroduced;