Actually respect suffixes on numeric literals.

- Add logic to extract the value and suffix from a numeric literal
  - This duplicates some of the lexing logic, but this is hard to avoid without redundant runtime work

- Note that I'm not using and stdlib string-to-number code. This should be more robust once it is working, but it is obviously error prone in the near term. The main up-sides to this are:
  - We can handle binary integer literals
  - We can handle hexadecimal floating-point literals without stdlib support
  - We can hypothetically support digit separators, if we ever wanted

- The parser looks at the suffix characters sliced off by the lexer, and tries to pick a type to use for a literal
  - It uses `NULL` if there is no suffix, to avoid some nasty order dependencies where the stdlib might need to parse a number before it has seen the definition of `int`
  - Right now I only handle a few cases, so there may be bugs lurking here

- The emit logic needs to handle the fact that a literal node in the AST might have a non-default type attached.
  - Right now I just quickly check for the most likely types, and emit the literal with a matching suffix. This doesn't seem robust if any source language supports a suffix for a type where a target has no corresponding suffix. In the long term some amount of casting is probably required.

1 files changed, 25 insertions, 0 deletions

diff --git a/tests/hlsl/simple/literal-typing.hlsl b/tests/hlsl/simple/literal-typing.hlsl
new file mode 100644
index 000000000..71acb0d92
--- /dev/null
+++ b/tests/hlsl/simple/literal-typing.hlsl
@@ -0,0 +1,25 @@
+//TEST:COMPARE_HLSL: -target dxbc-assembly -profile cs_5_0 -entry main
+
+// Confirm that we get the typing of literal suffixes correct
+
+// A type created to cause type-checking failures downstream
+struct Bad { int bad; };
+
+// We define two overloads for `foo()`. The "right" one takes
+// an unsigned integer, and returns it. The "wrong" one takes
+// a signed integer and returns a `Bad`.
+
+uint foo(uint x) { return x; }
+Bad foo(int x) { Bad b; b.bad = x; return b; }
+
+// The shader entry point will call `foo()` on a literal
+// with a suffix that should make it unsigned, so that
+// we either respect the suffix and call the right overload,
+// or ignore it and call the wrong one.
+
+RWStructuredBuffer<uint> b;
+[numthreads(32,1,1)]
+void main(uint3 tid : SV_DispatchThreadID)
+{
+	b[tid.x] = foo(99u);
+}
\ No newline at end of file