[PATCH] Creating a printing policy for "half"

[Yunzhong Gao]

ygao added you to the CC list for the revision "Creating a printing policy for "half"".

Hi,
Since "half" is an OpenCL keyword and clang accepts __fp16 as an extension for other languages,
error messages and metadata (and hence debug info) should refer to the half-precision floating point
as "__fp16" instead of "half" when compiling for non-OpenCL languages. This patch creates a new
printing policy for half in a similar manner to what is done for bool and wchar_t.

Can someone take a look whether this seems reasonable?
- Gao

http://llvm-reviews.chandlerc.com/D2952

Files:
  include/clang/AST/PrettyPrinter.h
  include/clang/Basic/LangOptions.def
  lib/AST/Type.cpp
  lib/Frontend/CompilerInvocation.cpp
  test/CXX/expr/expr.const/p2-0x.cpp
  test/Sema/variadic-promotion.c

Index: include/clang/AST/PrettyPrinter.h
===================================================================
--- include/clang/AST/PrettyPrinter.h
+++ include/clang/AST/PrettyPrinter.h
@@ -41,7 +41,7 @@
       ConstantArraySizeAsWritten(false), AnonymousTagLocations(true),
       SuppressStrongLifetime(false), SuppressLifetimeQualifiers(false),
       Bool(LO.Bool), TerseOutput(false), PolishForDeclaration(false),
-      MSWChar(LO.MicrosoftExt && !LO.WChar),
+      Half(LO.Half), MSWChar(LO.MicrosoftExt && !LO.WChar),
       IncludeNewlines(true) { }
 
   /// \brief What language we're printing.
@@ -153,6 +153,10 @@
   ///
   unsigned PolishForDeclaration : 1;
 
+  /// \brief When true, print the half-precision floating-point type as 'half'
+  /// instead of '__fp16'
+  unsigned Half : 1;
+
   /// \brief When true, print the built-in wchar_t type as __wchar_t. For use in
   /// Microsoft mode when wchar_t is not available.
   unsigned MSWChar : 1;
Index: include/clang/Basic/LangOptions.def
===================================================================
--- include/clang/Basic/LangOptions.def
+++ include/clang/Basic/LangOptions.def
@@ -61,6 +61,7 @@
 LANGOPT(Trigraphs         , 1, 0,"trigraphs")
 LANGOPT(LineComment       , 1, 0, "'//' comments")
 LANGOPT(Bool              , 1, 0, "bool, true, and false keywords")
+LANGOPT(Half              , 1, 0, "half keyword")
 LANGOPT(WChar             , 1, CPlusPlus, "wchar_t keyword")
 BENIGN_LANGOPT(DollarIdents   , 1, 1, "'$' in identifiers")
 BENIGN_LANGOPT(AsmPreprocessor, 1, 0, "preprocessor in asm mode")
Index: lib/AST/Type.cpp
===================================================================
--- lib/AST/Type.cpp
+++ lib/AST/Type.cpp
@@ -1523,7 +1523,7 @@
   case ULong:             return "unsigned long";
   case ULongLong:         return "unsigned long long";
   case UInt128:           return "unsigned __int128";
-  case Half:              return "half";
+  case Half:              return Policy.Half ? "half" : "__fp16";
   case Float:             return "float";
   case Double:            return "double";
   case LongDouble:        return "long double";
Index: lib/Frontend/CompilerInvocation.cpp
===================================================================
--- lib/Frontend/CompilerInvocation.cpp
+++ lib/Frontend/CompilerInvocation.cpp
@@ -1112,6 +1114,9 @@
   // OpenCL and C++ both have bool, true, false keywords.
   Opts.Bool = Opts.OpenCL || Opts.CPlusPlus;
 
+  // OpenCL has half keyword
+  Opts.Half = Opts.OpenCL;
+
   // C++ has wchar_t keyword.
   Opts.WChar = Opts.CPlusPlus;
 
Index: test/CXX/expr/expr.const/p2-0x.cpp
===================================================================
--- test/CXX/expr/expr.const/p2-0x.cpp
+++ test/CXX/expr/expr.const/p2-0x.cpp
@@ -138,7 +138,7 @@
     case (int)(unsigned)(long long)4.4e9: // ok
     case (int)(float)1e300: // expected-error {{constant expression}} expected-note {{value 1.0E+300 is outside the range of representable values of type 'float'}} expected-error {{duplicate case value '2147483647'}} expected-note {{previous case defined here}}
     case (int)((float)1e37 / 1e30): // ok
-    case (int)(__fp16)65536: // expected-error {{constant expression}} expected-note {{value 65536 is outside the range of representable values of type 'half'}} expected-error {{duplicate case value '2147483647'}}
+    case (int)(__fp16)65536: // expected-error {{constant expression}} expected-note {{value 65536 is outside the range of representable values of type '__fp16'}} expected-error {{duplicate case value '2147483647'}}
       break;
     }
   }
Index: test/Sema/variadic-promotion.c
===================================================================
--- test/Sema/variadic-promotion.c
+++ test/Sema/variadic-promotion.c
@@ -6,7 +6,7 @@
   variadic(3, *f16, f32, f64);
 
 // CHECK: ImplicitCastExpr {{.*}} 'double' <FloatingCast>
-// CHECK-NEXT: 'half'
+// CHECK-NEXT: '__fp16'
 
 // CHECK: ImplicitCastExpr {{.*}} 'double' <FloatingCast>
 // CHECK-NEXT: 'float'
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