Work towards target-specific function overloads (#210)

* Checkpoint: interface conformance work

- Add explicit definition of `saturate` for the GLSL target, which calls through to `clamp`

- Needed to add explicit initializer to `__BuiltinFloatingPointType` to allow initialization from a single `float`, so that the `saturate` implementation can be sure that it can initialize a `T` from `0.0` or `1.0`.

- This triggered errors in overload resolution, because the logic in place could not figure out that the `T` of the outer generic (`saturate<T>()`) conformed to the interface required by the callee.

At this point I have the call to the scalar `clamp()` getting past type-checking, but not the vector or matrix cases.

* More fixups for overload resolution inside generics

- Make sure value parameters are treated the same as type parameters: we only want to solve for the parameters of the generic actually being applied, and not accidentally generate constraints for outer generics (e.g., when checking the body of a generic function).

- Make sure that the diagnostics stuff uses the correct source manager when expanding the location of a builtin.

* Fixes for function redeclaration

- Handle case of redeclaring a generic function
  - Enumerate siblings in the parent of the *generic* not the parent of the *function*
  - Add logic to compare generic signatures
  - When generic signatures match, specialize functions to compatible generic arguments before comparing the function signatures

- Fix redeclaration logic to *not* detect prefix/postifx operators as redeclarations of one another

- Build an explicit representation of function redeclaration groups
  - First declaration is the "primary" and others are stored in a linked list

- Make overload resolution handle redeclared functions
  - Only consider the primary declaration and skip others

1 files changed, 12 insertions, 0 deletions

diff --git a/source/slang/parser.cpp b/source/slang/parser.cpp
index a0e07ea12..2b6535bef 100644
--- a/source/slang/parser.cpp
+++ b/source/slang/parser.cpp
@@ -3842,6 +3842,17 @@ namespace Slang
         return modifier;
     }
 
+    static RefPtr<RefObject> parseSpecializedForTargetModifier(Parser* parser, void* /*userData*/)
+    {
+        auto modifier = new SpecializedForTargetModifier();
+        if (AdvanceIf(parser, TokenType::LParent))
+        {
+            modifier->targetToken = parser->ReadToken(TokenType::Identifier);
+            parser->ReadToken(TokenType::RParent);
+        }
+        return modifier;
+    }
+
     static RefPtr<RefObject> parseGLSLExtensionModifier(Parser* parser, void* /*userData*/)
     {
         auto modifier = new RequiredGLSLExtensionModifier();
@@ -4057,6 +4068,7 @@ namespace Slang
 
         MODIFIER(__intrinsic_op,        parseIntrinsicOpModifier);
         MODIFIER(__target_intrinsic,    parseTargetIntrinsicModifier);
+        MODIFIER(__specialized_for_target,    parseSpecializedForTargetModifier);
         MODIFIER(__glsl_extension,  parseGLSLExtensionModifier);
         MODIFIER(__glsl_version,    parseGLSLVersionModifier);