[Fixed Point Arithmetic] Fixed Point Precision Bits and Fixed Point Literals

This diff includes the logic for setting the precision bits for each primary fixed point type in the target info and logic for initializing a fixed point literal.

Fixed point literals are declared using the suffixes

```
hr: short _Fract
uhr: unsigned short _Fract
r: _Fract
ur: unsigned _Fract
lr: long _Fract
ulr: unsigned long _Fract
hk: short _Accum
uhk: unsigned short _Accum
k: _Accum
uk: unsigned _Accum
```
Errors are also thrown for illegal literal values

```
unsigned short _Accum u_short_accum = 256.0uhk;   // expected-error{{the integral part of this literal is too large for this unsigned _Accum type}}
```

Differential Revision: https://reviews.llvm.org/D46915

llvm-svn: 335148

1 files changed, 31 insertions, 0 deletions

diff --git a/clang/lib/AST/Expr.cpp b/clang/lib/AST/Expr.cpp
index b2593ef4675..47cf026e28e 100644
--- a/clang/lib/AST/Expr.cpp
+++ b/clang/lib/AST/Expr.cpp
@@ -755,6 +755,36 @@ IntegerLiteral::Create(const ASTContext &C, EmptyShell Empty) {
   return new (C) IntegerLiteral(Empty);
 }
 
+FixedPointLiteral::FixedPointLiteral(const ASTContext &C, const llvm::APInt &V,
+                                     QualType type, SourceLocation l,
+                                     unsigned Scale)
+    : Expr(FixedPointLiteralClass, type, VK_RValue, OK_Ordinary, false, false,
+           false, false),
+      Loc(l), Scale(Scale) {
+  assert(type->isFixedPointType() && "Illegal type in FixedPointLiteral");
+  assert(V.getBitWidth() == C.getTypeInfo(type).Width &&
+         "Fixed point type is not the correct size for constant.");
+  setValue(C, V);
+}
+
+FixedPointLiteral *FixedPointLiteral::CreateFromRawInt(const ASTContext &C,
+                                                       const llvm::APInt &V,
+                                                       QualType type,
+                                                       SourceLocation l,
+                                                       unsigned Scale) {
+  return new (C) FixedPointLiteral(C, V, type, l, Scale);
+}
+
+std::string FixedPointLiteral::getValueAsString(unsigned Radix) const {
+  // Currently the longest decimal number that can be printed is the max for an
+  // unsigned long _Accum: 4294967295.99999999976716935634613037109375
+  // which is 43 characters.
+  SmallString<64> S;
+  FixedPointValueToString(
+      S, llvm::APSInt::getUnsigned(getValue().getZExtValue()), Scale, Radix);
+  return S.str();
+}
+
 FloatingLiteral::FloatingLiteral(const ASTContext &C, const llvm::APFloat &V,
                                  bool isexact, QualType Type, SourceLocation L)
   : Expr(FloatingLiteralClass, Type, VK_RValue, OK_Ordinary, false, false,
@@ -2991,6 +3021,7 @@ bool Expr::HasSideEffects(const ASTContext &Ctx,
   case ObjCIvarRefExprClass:
   case PredefinedExprClass:
   case IntegerLiteralClass:
+  case FixedPointLiteralClass:
   case FloatingLiteralClass:
   case ImaginaryLiteralClass:
   case StringLiteralClass: