[WebAssembly] Add preprocessor define for half-precision (#90528)

This adds the preprocessor define for the half-precision feature and
also adds preprocessor tests.

Author: aheejin

clang/lib/Basic/Targets/WebAssembly.cpp

@@ -100,6 +100,8 @@ void WebAssemblyTargetInfo::getTargetDefines(const LangOptions &Opts,
     Builder.defineMacro("__wasm_extended_const__");
   if (HasMultiMemory)
     Builder.defineMacro("__wasm_multimemory__");
+  if (HasHalfPrecision)
+    Builder.defineMacro("__wasm_half_precision__");
 
   Builder.defineMacro("__GCC_HAVE_SYNC_COMPARE_AND_SWAP_1");
   Builder.defineMacro("__GCC_HAVE_SYNC_COMPARE_AND_SWAP_2");

clang/test/Preprocessor/wasm-target-features.c

@@ -43,6 +43,15 @@
 //
 // EXTENDED-CONST: #define __wasm_extended_const__ 1{{$}}
 
+// RUN: %clang -E -dM %s -o - 2>&1 \
+// RUN:     -target wasm32-unknown-unknown -mhalf-precision \
+// RUN:   | FileCheck %s -check-prefix=HALF-PRECISION
+// RUN: %clang -E -dM %s -o - 2>&1 \
+// RUN:     -target wasm64-unknown-unknown -mhalf-precision \
+// RUN:   | FileCheck %s -check-prefix=HALF-PRECISION
+//
+// HALF-PRECISION: #define __wasm_half_precision__ 1{{$}}
+
 // RUN: %clang -E -dM %s -o - 2>&1 \
 // RUN:     -target wasm32-unknown-unknown -mmultimemory \
 // RUN:   | FileCheck %s -check-prefix=MULTIMEMORY
@@ -135,6 +144,7 @@
 // MVP-NOT: #define __wasm_bulk_memory__ 1{{$}}
 // MVP-NOT: #define __wasm_exception_handling__ 1{{$}}
 // MVP-NOT: #define __wasm_extended_const__ 1{{$}}
+// MVP-NOT: #define __wasm_half_precision__ 1{{$}}
 // MVP-NOT: #define __wasm_multimemory__ 1{{$}}
 // MVP-NOT: #define __wasm_multivalue__ 1{{$}}
 // MVP-NOT: #define __wasm_mutable_globals__ 1{{$}}
@@ -168,6 +178,7 @@
 // GENERIC-NOT: #define __wasm_bulk_memory__ 1{{$}}
 // GENERIC-NOT: #define __wasm_exception_handling__ 1{{$}}
 // GENERIC-NOT: #define __wasm_extended_const__ 1{{$}}
+// GENERIC-NOT: #define __wasm_half_precision__ 1{{$}}
 // GENERIC-NOT: #define __wasm_multimemory__ 1{{$}}
 // GENERIC-NOT: #define __wasm_nontrapping_fptoint__ 1{{$}}
 // GENERIC-NOT: #define __wasm_relaxed_simd__ 1{{$}}
@@ -183,6 +194,7 @@
 //
 // BLEEDING-EDGE-INCLUDE-DAG: #define __wasm_atomics__ 1{{$}}
 // BLEEDING-EDGE-INCLUDE-DAG: #define __wasm_bulk_memory__ 1{{$}}
+// BLEEDING-EDGE-INCLUDE-DAG: #define __wasm_half_precision__ 1{{$}}
 // BLEEDING-EDGE-INCLUDE-DAG: #define __wasm_multimemory__ 1{{$}}
 // BLEEDING-EDGE-INCLUDE-DAG: #define __wasm_multivalue__ 1{{$}}
 // BLEEDING-EDGE-INCLUDE-DAG: #define __wasm_mutable_globals__ 1{{$}}