Support __target_intrinsic modifiers in IR codegen (#401)

The standard library already has a bunch of these decorations, since they were added to support Slang->Vulkan codegen on the AST-to-AST path. This change makes the IR code generator able to exploit the modifiers so that we pick up a bunch of Vulkan support "for free" in the short term.

The basic change is in `lower-to-ir.cpp` where we copy over any `TargetIntrinsicModifier`s to become `IRTargetIntrinsicDecoration`s with the same information. We then need a bit of logic in `ir.cpp` to make sure we clone them as needed.

The core work of using the modifiers is in `emit.cpp`, where I basically just copy-pasted the existing logic that applied in the AST path (all the AST-related code there is dead, and we should clean it up soon).

The big change that comes with this logic is that when dealing with a member function, the numbering of the argument used in the intrinsic definition string changes, so that `$0` refers to the base object (whereas before the base object was looked up via the base expression of a `MemberExpr` used for the function). This requires a bunch of the definitions in the library to be updated; hopefully I caught them all.

For kicks, I've re-enabled a cross-compilation test just to confirm that we are generating valid SPIR-V for code that performs texture-fetch operations. I don't expect us to keep that test enabled as-is in the long term, though, because it would be much better to instead use render-test to do the same thing. Alas, beefing up the Vulkan support in render-test is an outstanding work item, and I didn't want to pollute this change with more work along those lines.

2 files changed, 23 insertions, 16 deletions

diff --git a/tests/bindings/glsl-parameter-blocks.slang b/tests/bindings/glsl-parameter-blocks.slang
index 64e302d90..48eacbb0f 100644
--- a/tests/bindings/glsl-parameter-blocks.slang
+++ b/tests/bindings/glsl-parameter-blocks.slang
@@ -1,5 +1,5 @@
 #version 450 core
-//TEST_DISABLED:CROSS_COMPILE: -profile ps_5_0 -entry main -target spirv-assembly
+//TEST:CROSS_COMPILE: -profile ps_5_0 -entry main -target spirv-assembly
 
 // Note: disabled because the translation of `Texture2D.Sample()`
 // requires handling of local variables with resource types in the IR.
diff --git a/tests/bindings/glsl-parameter-blocks.slang.glsl b/tests/bindings/glsl-parameter-blocks.slang.glsl
index 9956800f1..e34101983 100644
--- a/tests/bindings/glsl-parameter-blocks.slang.glsl
+++ b/tests/bindings/glsl-parameter-blocks.slang.glsl
@@ -1,37 +1,44 @@
 //TEST_IGNORE_FILE:
 #version 450 core
 
-struct Test
+struct _ST04Test
 {
     vec4 a;
 };
 
 layout(binding = 0, set = 1)
-uniform gTest_S1
+uniform _S1
 {
-    Test gTest;
+    _ST04Test _SV05gTestL0;
 };
 
 layout(binding = 1, set = 1)
-uniform texture2D gTest_t;
+uniform texture2D _SV05gTestL1;
 
 layout(binding = 2, set = 1)
-uniform sampler gTest_s;
-
-vec4 main_(vec2 uv)
-{
-    return gTest.a + texture(sampler2D(gTest_t, gTest_s), uv);
-}
+uniform sampler _SV05gTestL2;
 
 layout(location = 0)
-in vec2 SLANG_in_uv;
+in vec2 _S3;
 
 layout(location = 0)
-out vec4 SLANG_out_main_result;
+out vec4 _S2;
 
 void main()
 {
-    vec2 uv = SLANG_in_uv;
-    vec4 main_result = main_(uv);
-    SLANG_out_main_result = main_result;
+	vec2 _S4 = _S3;
+
+	vec2 _S5 = _S4;
+
+	vec4 _S6 = _SV05gTestL0.a;
+
+	vec2 _S7 = _S5;
+
+
+    vec4 _S8 = texture(sampler2D(_SV05gTestL1, _SV05gTestL2), _S7);
+
+    vec4 _S9 = _S6 + _S8;
+	_S2 = _S9;
+
+	return;
 }