Add size_t, ptrdiff_t, and [u]intptr_t types.

docs/ispc.rst

@@ -1394,8 +1394,8 @@ Types
 Basic Types and Type Qualifiers
 -------------------------------
 
-``ispc`` is a statically-typed language.  It supports a variety of basic
+``ispc`` is a statically-typed language.  It supports a variety of core
-types.
+basic types:
 
 * ``void``: "empty" type representing no value.
 * ``bool``: boolean value; may be assigned ``true``, ``false``, or the
@@ -1412,6 +1412,15 @@ types.
 * ``unsigned int64``: 64-bit unsigned integer.
 * ``double``: 64-bit double-precision floating point value.
 
+There are also a few built-in types related to pointers and memory:
+
+* ``size_t``: the maximum size of any object (structure or array)
+* ``ptrdiff_t``: an integer type large enough to represent the difference
+  between two pointers
+* ``intptr_t``: signed integer type that is large enough to represent
+  a pointer value
+* ``uintptr_t``: unsigned integer type large enough to represent a pointer
+
 Implicit type conversion between values of different types is done
 automatically by the ``ispc`` compiler.  Thus, a value of ``float`` type
 can be assigned to a variable of ``int`` type directly.  In binary

module.cpp

@@ -88,6 +88,24 @@
 #include <llvm/Support/raw_ostream.h>
 #include <llvm/Bitcode/ReaderWriter.h>
 
+static void
+lDeclareSizeAndPtrIntTypes(SymbolTable *symbolTable) {
+    const Type *ptrIntType = (g->target.is32Bit) ? AtomicType::VaryingInt32 :
+        AtomicType::VaryingInt64;
+    ptrIntType = ptrIntType->GetAsUnboundVariabilityType();
+
+    symbolTable->AddType("intptr_t", ptrIntType, SourcePos());
+    symbolTable->AddType("uintptr_t", ptrIntType->GetAsUnsignedType(),
+                         SourcePos());
+    symbolTable->AddType("ptrdiff_t", ptrIntType, SourcePos());
+
+    const Type *sizeType = (g->target.is32Bit || g->opt.force32BitAddressing) ?
+        AtomicType::VaryingInt32 : AtomicType::VaryingInt64;
+    sizeType = sizeType->GetAsUnboundVariabilityType();
+    symbolTable->AddType("size_t", sizeType, SourcePos());
+}
+
+
 ///////////////////////////////////////////////////////////////////////////
 // Module
 
@@ -103,6 +121,8 @@ Module::Module(const char *fn) {
     symbolTable = new SymbolTable;
     ast = new AST;
 
+    lDeclareSizeAndPtrIntTypes(symbolTable);
+
     module = new llvm::Module(filename ? filename : "<stdin>", *g->ctx);
     module->setTargetTriple(g->target.GetTripleString());
 

tests/intptr.ispc

@@ -0,0 +1,19 @@
+
+export uniform int width() { return programCount; }
+
+
+export void f_v(uniform float RET[]) {
+    RET[programIndex] = sizeof(uniform intptr_t);
+}
+
+export void result(uniform float RET[]) {
+    RET[programIndex] = 
+#if (ISPC_POINTER_SIZE==32)
+        4
+#elif (ISPC_POINTER_SIZE==64)
+        8
+#else
+#error Unknown pointer size
+#endif
+        ;
+}