Improve support for non-32-bit types. (#643)

The main change here is to fill out the `BaseType` enumeration so that it covers the full range of 8/16/32/64-bit signed and unsigned integers, as well as 16/32/64-bit floating-point numbers, and then propagate that completion through various places in the code.

More details:

* The current `half`, `float`, `double`, `int`, and `uint` types are still the default names for their types, so things like `float16_t` and `int32_t` were added as `typedef`s.

* We still need to generate the full gamut of vector/matrix `typedef`s for the new types, so that things like `float16_t4x3` will work (yes, I know that is ugly as sin, but that's the HLSL syntax...).

* A few pieces of dead code from earlier in the compiler's life got removed, since I did a find-in-files for `BaseType::` and tried to either update or delete every site.

* A few call sites that were enumerating integer base types in an ad-hoc fashion were changed to use a single `isIntegerBaseType()` function that I added in `check.cpp`

* When compiling with dxc for shader model 6.2 and up, we enable the compiler's support for native 16-bit types via a flag.

* The public API enumeration for reflection of scalar types added cases for 8- and 16-bit integers (it already exposed the other cases we need)

* The lexer was updated to be extremely liberal in what kinds of suffixes it allows on literals. I also removed the logic that was treating, e.g., `0f` as a floating-point literal (it doesn't seem to be the right behavior). That would now be an integer literal with an invalid suffix.

* The logic in the parser that applies types to literals was updated to handle a few more cases: `LL` and `ULL` for 64-bit integers, and `H` for 16-bit floats.

* The mangling logic needed to be updated to handle the new cases, and I consolidated the handling of those types in their front-end and IR forms.

* Removed the explicit `BasicExpressionType::ToString` logic, since all basic types are `DeclRefType`s in the front end, and we can just print them out as such.

* As a bit of a gross hack, fudged the conversion costs so that `int` to `int64_t` conversion is a bit more costly. The problem there is that given an operation like `int(0) + uint(0)`, the best applicable candidates ended up being `+(uint,uint)` and `+(int64_t,int64_t)` because the cost of a single `int`-to-`uint` conversion was the same as the sum of the cost of an `int`-to-`int64_t` and a `uint`-to-`int64_t`. A better long-term fix here is to completely change our overload resolution strategy, but that is obviously way too big to squeeze into this change.

* Type layout computation was updated to handle all the new types and give them their natural size/alignment. Note that this does *not* work for down-level HLSL where `half` is treated as a synonym for `float`. It also doesn't deal with the fact that many of these types aren't actually allowed in constant buffers for certain shader models. A future change should work to add error messages for unsupported stuff during type layout (or just make the types themselves require support for certain capabilities)

1 files changed, 36 insertions, 4 deletions

diff --git a/source/slang/core.meta.slang b/source/slang/core.meta.slang
index 31da44f3c..b5b78c2e5 100644
--- a/source/slang/core.meta.slang
+++ b/source/slang/core.meta.slang
@@ -1,5 +1,14 @@
 // Slang `core` library
 
+// Aliases for base types
+typedef half float16_t;
+typedef float float32_t;
+typedef double float64_t;
+
+typedef int int32_t;
+typedef uint uint32_t;
+
+
 // Modifier for variables that must resolve to compile-time constants
 // as part of translation.
 syntax constexpr : ConstExprModifier;
@@ -72,9 +81,14 @@ for (int tt = 0; tt < kBaseTypeCount; ++tt)
         sb << "\n    , __BuiltinFloatingPointType\n";
         sb << "\n    ,  __BuiltinRealType\n";
         // fall through to:
+    case BaseType::Int8:
+    case BaseType::Int16:
     case BaseType::Int:
+    case BaseType::Int64:
         sb << "\n    ,  __BuiltinSignedArithmeticType\n";
         // fall through to:
+    case BaseType::UInt8:
+    case BaseType::UInt16:
     case BaseType::UInt:
     case BaseType::UInt64:
         sb << "\n    ,  __BuiltinArithmeticType\n";
@@ -121,6 +135,7 @@ for (int tt = 0; tt < kBaseTypeCount; ++tt)
     //
     switch (kBaseTypes[tt].tag)
     {
+        // TODO: should this cover the full gamut of integer types?
     case BaseType::Int:
     case BaseType::UInt:
 }}}}
@@ -196,10 +211,27 @@ static const struct {
     char const* glslPrefix;
 } kTypes[] =
 {
-    {"float", ""},
-    {"int", "i"},
-    {"uint", "u"},
-    {"bool", "b"},
+    {"half",        "f16"},
+    {"float",       ""},
+    {"double",      "d"},
+
+    {"float16_t",   "f16"},
+    {"float32_t",   "f32"},
+    {"float64_t",   "f64"},
+
+    {"int8_t",      "i8"},
+    {"int16_t",     "i16"},
+    {"int32_t",     "i32"},
+    {"int",         "i"},
+    {"int64_t",     "i64"},
+
+    {"uint8_t",     "u8"},
+    {"uint16_t",    "u16"},
+    {"uint32_t",    "u32"},
+    {"uint",        "u"},
+    {"uint64_t",    "u64"},
+
+    {"bool",        "b"},
 };
 static const int kTypeCount = sizeof(kTypes) / sizeof(kTypes[0]);