Make sizeof(T) & alignof(T) of generic types work as compile-time constants (#7213)

* Make sizeof(generic) work as compile-time constant

* format code

---------

Co-authored-by: slangbot <186143334+slangbot@users.noreply.github.com>

1 files changed, 101 insertions, 0 deletions

diff --git a/source/slang/slang-ast-val.cpp b/source/slang/slang-ast-val.cpp
index 1cdca0440..92e170515 100644
--- a/source/slang/slang-ast-val.cpp
+++ b/source/slang/slang-ast-val.cpp
@@ -3,6 +3,7 @@
 
 #include "slang-ast-builder.h"
 #include "slang-ast-dispatch.h"
+#include "slang-ast-natural-layout.h"
 #include "slang-check-impl.h"
 #include "slang-diagnostics.h"
 #include "slang-mangle.h"
@@ -1742,6 +1743,106 @@ Val* FuncCallIntVal::_substituteImplOverride(
     return this;
 }
 
+// !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! SizeOfIntVal !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
+
+void SizeOfIntVal::_toTextOverride(StringBuilder& out)
+{
+    out << "sizeof(";
+    getTypeArg()->toText(out);
+    out << ")";
+}
+
+Val* SizeOfIntVal::tryFoldOrNull(ASTBuilder* astBuilder, Type* intType, Type* newType)
+{
+    ASTNaturalLayoutContext context(astBuilder, nullptr);
+    const auto size = context.calcSize(newType);
+
+    if (!size)
+        return nullptr;
+
+    return astBuilder->getIntVal(intType, size.size);
+}
+
+Val* SizeOfIntVal::tryFold(ASTBuilder* astBuilder, Type* intType, Type* newType)
+{
+    if (auto result = tryFoldOrNull(astBuilder, intType, newType))
+        return result;
+    auto result = astBuilder->getOrCreate<SizeOfIntVal>(intType, newType);
+    return result;
+}
+
+Val* SizeOfIntVal::_substituteImplOverride(
+    ASTBuilder* astBuilder,
+    SubstitutionSet subst,
+    int* ioDiff)
+{
+    int diff = 0;
+    auto newType = as<Type>(getTypeArg()->substituteImpl(astBuilder, subst, &diff));
+    if (!diff)
+        return this;
+
+    (*ioDiff)++;
+    return tryFold(astBuilder, getType(), newType);
+}
+
+Val* SizeOfIntVal::_resolveImplOverride()
+{
+    auto resolvedTypeArg = getTypeArg()->resolve();
+    if (resolvedTypeArg == getTypeArg())
+        return this;
+    return tryFold(getCurrentASTBuilder(), getType(), as<Type>(resolvedTypeArg));
+}
+
+// !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! AlignOfIntVal !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
+
+void AlignOfIntVal::_toTextOverride(StringBuilder& out)
+{
+    out << "alignof(";
+    getTypeArg()->toText(out);
+    out << ")";
+}
+
+Val* AlignOfIntVal::tryFoldOrNull(ASTBuilder* astBuilder, Type* intType, Type* newType)
+{
+    ASTNaturalLayoutContext context(astBuilder, nullptr);
+    const auto size = context.calcSize(newType);
+
+    if (!size)
+        return nullptr;
+
+    return astBuilder->getIntVal(intType, size.alignment);
+}
+
+Val* AlignOfIntVal::tryFold(ASTBuilder* astBuilder, Type* intType, Type* newType)
+{
+    if (auto result = tryFoldOrNull(astBuilder, intType, newType))
+        return result;
+    auto result = astBuilder->getOrCreate<AlignOfIntVal>(intType, newType);
+    return result;
+}
+
+Val* AlignOfIntVal::_substituteImplOverride(
+    ASTBuilder* astBuilder,
+    SubstitutionSet subst,
+    int* ioDiff)
+{
+    int diff = 0;
+    auto newType = as<Type>(getTypeArg()->substituteImpl(astBuilder, subst, &diff));
+    if (!diff)
+        return this;
+
+    (*ioDiff)++;
+    return tryFold(astBuilder, getType(), newType);
+}
+
+Val* AlignOfIntVal::_resolveImplOverride()
+{
+    auto resolvedTypeArg = getTypeArg()->resolve();
+    if (resolvedTypeArg == getTypeArg())
+        return this;
+    return tryFold(getCurrentASTBuilder(), getType(), as<Type>(resolvedTypeArg));
+}
+
 // !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! CountOfIntVal !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
 
 void CountOfIntVal::_toTextOverride(StringBuilder& out)