[clang] 39172bc - [HLSL] Cleanup TargetInfo handling (#90694)

[via cfe-commits]

Author: Chris B
Date: 2024-05-02T17:15:57-05:00
New Revision: 39172bcfe4ca6f4db09da0f76a3e324dd3888a51

URL: https://github.com/llvm/llvm-project/commit/39172bcfe4ca6f4db09da0f76a3e324dd3888a51
DIFF: https://github.com/llvm/llvm-project/commit/39172bcfe4ca6f4db09da0f76a3e324dd3888a51.diff

LOG: [HLSL] Cleanup TargetInfo handling (#90694)

We had some odd places where we set target behaviors. We were setting
the long size in target-specific code, but it should be language-based.
We were not setting the Half float type semantics correctly, and instead
were overriding the query in the AST context.

This change it moves existing code to the right places in the Target so
that as we continue working on target and language feature they are
controlled in the right places.

It also fixes a bug where the size of `half` was computed incorrectly
when native half types are not supported.

Added: 
    clang/test/SemaHLSL/Types/Arithmetic/half_size.hlsl

Modified: 
    clang/lib/AST/ASTContext.cpp
    clang/lib/Basic/TargetInfo.cpp
    clang/lib/Basic/Targets/DirectX.h

Removed: 
    


################################################################################
diff  --git a/clang/lib/AST/ASTContext.cpp b/clang/lib/AST/ASTContext.cpp
index 03014568f8fe66..699721aabdb5e1 100644
--- a/clang/lib/AST/ASTContext.cpp
+++ b/clang/lib/AST/ASTContext.cpp
@@ -1612,15 +1612,7 @@ const llvm::fltSemantics &ASTContext::getFloatTypeSemantics(QualType T) const {
   case BuiltinType::Float16:
     return Target->getHalfFormat();
   case BuiltinType::Half:
-    // For HLSL, when the native half type is disabled, half will be treat as
-    // float.
-    if (getLangOpts().HLSL)
-      if (getLangOpts().NativeHalfType)
-        return Target->getHalfFormat();
-      else
-        return Target->getFloatFormat();
-    else
-      return Target->getHalfFormat();
+    return Target->getHalfFormat();
   case BuiltinType::Float:      return Target->getFloatFormat();
   case BuiltinType::Double:     return Target->getDoubleFormat();
   case BuiltinType::Ibm128:

diff  --git a/clang/lib/Basic/TargetInfo.cpp b/clang/lib/Basic/TargetInfo.cpp
index f96956f31d50dc..29f5cd14e46e11 100644
--- a/clang/lib/Basic/TargetInfo.cpp
+++ b/clang/lib/Basic/TargetInfo.cpp
@@ -406,6 +406,16 @@ void TargetInfo::adjust(DiagnosticsEngine &Diags, LangOptions &Opts) {
     LongDoubleAlign = 64;
   }
 
+  // HLSL explicitly defines the sizes and formats of some data types, and we
+  // need to conform to those regardless of what architecture you are targeting.
+  if (Opts.HLSL) {
+    LongWidth = LongAlign = 64;
+    if (!Opts.NativeHalfType) {
+      HalfFormat = &llvm::APFloat::IEEEsingle();
+      HalfWidth = HalfAlign = 32;
+    }
+  }
+
   if (Opts.OpenCL) {
     // OpenCL C requires specific widths for types, irrespective of
     // what these normally are for the target.

diff  --git a/clang/lib/Basic/Targets/DirectX.h b/clang/lib/Basic/Targets/DirectX.h
index acfcc8c47ba950..a084e2823453fc 100644
--- a/clang/lib/Basic/Targets/DirectX.h
+++ b/clang/lib/Basic/Targets/DirectX.h
@@ -53,7 +53,6 @@ class LLVM_LIBRARY_VISIBILITY DirectXTargetInfo : public TargetInfo {
       : TargetInfo(Triple) {
     TLSSupported = false;
     VLASupported = false;
-    LongWidth = LongAlign = 64;
     AddrSpaceMap = &DirectXAddrSpaceMap;
     UseAddrSpaceMapMangling = true;
     HasLegalHalfType = true;

diff  --git a/clang/test/SemaHLSL/Types/Arithmetic/half_size.hlsl b/clang/test/SemaHLSL/Types/Arithmetic/half_size.hlsl
new file mode 100644
index 00000000000000..7de46746999304
--- /dev/null
+++ b/clang/test/SemaHLSL/Types/Arithmetic/half_size.hlsl
@@ -0,0 +1,11 @@
+// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.4-library -verify %s
+// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.4-library -verify -fnative-half-type %s
+// RUN: %clang_cc1 -triple spirv-linux-vulkan-library -verify %s
+// RUN: %clang_cc1 -triple spirv-linux-vulkan-library -verify -fnative-half-type %s
+
+// expected-no-diagnostics
+#ifdef __HLSL_ENABLE_16_BIT
+_Static_assert(sizeof(half) == 2, "half is 2 bytes");
+#else
+_Static_assert(sizeof(half) == 4, "half is 4 bytes");
+#endif