SPV: Fix #1783: Don't do bounds checking for spec-const-expression size

It's okay for symbolic spec-consts, but without constant folding,
not okay when the array size is an expression.

Test/baseResults/spv.specConstArrayCheck.vert.out

@@ -0,0 +1,6 @@
+spv.specConstArrayCheck.vert
+ERROR: 0:13: '[' :  array index out of range '6'
+ERROR: 1 compilation errors.  No code generated.
+
+
+SPIR-V is not generated for failed compile or link

Test/spv.specConstArrayCheck.vert

@@ -0,0 +1,14 @@
+#version 450
+
+layout(constant_id = 0) const uint a = 1;
+layout(constant_id = 1) const uint b = 2;
+layout(location = 0) out uint o;
+
+void main() {
+  uint arr1[a+a];
+  uint arr2[b];
+  o = arr1[1];
+  o = arr2[1];
+  o = arr1[6];
+  o = arr2[6];
+}

glslang/Include/revision.h

@@ -1,3 +1,3 @@
 // This header is generated by the make-revision script.
 
-#define GLSLANG_PATCH_LEVEL 3276
+#define GLSLANG_PATCH_LEVEL 3294

glslang/MachineIndependent/ParseContextBase.cpp

@@ -254,11 +254,17 @@ void TParseContextBase::trackLinkage(TSymbol& symbol)
 // Give an error if not.
 void TParseContextBase::checkIndex(const TSourceLoc& loc, const TType& type, int& index)
 {
+    const auto sizeIsSpecializationExpression = [&type]() {
+        return type.containsSpecializationSize() &&
+               type.getArraySizes()->getOuterNode() != nullptr &&
+               type.getArraySizes()->getOuterNode()->getAsSymbolNode() == nullptr; };
+
     if (index < 0) {
         error(loc, "", "[", "index out of range '%d'", index);
         index = 0;
     } else if (type.isArray()) {
-        if (type.isSizedArray() && index >= type.getOuterArraySize()) {
+        if (type.isSizedArray() && !sizeIsSpecializationExpression() &&
+            index >= type.getOuterArraySize()) {
             error(loc, "", "[", "array index out of range '%d'", index);
             index = type.getOuterArraySize() - 1;
         }

gtests/Spv.FromFile.cpp

@@ -545,6 +545,7 @@ INSTANTIATE_TEST_CASE_P(
         "vulkan.vert",
         "vulkan.comp",
         "samplerlessTextureFunctions.frag",
+        "spv.specConstArrayCheck.vert",
     })),
     FileNameAsCustomTestSuffix
 );