New language feature: basic error handling. (#2253)

* New language feature: basic error handling.

* Fix.

* Fix `tryCall` encoding according to code review.

Co-authored-by: Yong He <yhe@nvidia.com>

1 files changed, 15 insertions, 1 deletions

diff --git a/source/slang/slang-ast-type.cpp b/source/slang/slang-ast-type.cpp
index b6bc1f170..bcaf8f5a9 100644
--- a/source/slang/slang-ast-type.cpp
+++ b/source/slang/slang-ast-type.cpp
@@ -549,6 +549,11 @@ void FuncType::_toTextOverride(StringBuilder& out)
         out << getParamType(pp);
     }
     out << toSlice(") -> ") << getResultType();
+
+    if (!getErrorType()->equals(getASTBuilder()->getVoidType()))
+    {
+        out << " throws " << getErrorType();
+    }
 }
 
 bool FuncType::_equalsImplOverride(Type * type)
@@ -571,6 +576,9 @@ bool FuncType::_equalsImplOverride(Type * type)
         if (!resultType->equals(funcType->resultType))
             return false;
 
+        if (!errorType->equals(funcType->errorType))
+            return false;
+
         // TODO: if we ever introduce other kinds
         // of qualification on function types, we'd
         // want to consider it here.
@@ -586,6 +594,9 @@ Val* FuncType::_substituteImplOverride(ASTBuilder* astBuilder, SubstitutionSet s
     // result type
     Type* substResultType = as<Type>(resultType->substituteImpl(astBuilder, subst, &diff));
 
+    // error type
+    Type* substErrorType = as<Type>(errorType->substituteImpl(astBuilder, subst, &diff));
+
     // parameter types
     List<Type*> substParamTypes;
     for (auto pp : paramTypes)
@@ -601,6 +612,7 @@ Val* FuncType::_substituteImplOverride(ASTBuilder* astBuilder, SubstitutionSet s
     FuncType* substType = astBuilder->create<FuncType>();
     substType->resultType = substResultType;
     substType->paramTypes = substParamTypes;
+    substType->errorType = substErrorType;
     return substType;
 }
 
@@ -608,6 +620,7 @@ Type* FuncType::_createCanonicalTypeOverride()
 {
     // result type
     Type* canResultType = resultType->getCanonicalType();
+    Type* canErrorType = errorType->getCanonicalType();
 
     // parameter types
     List<Type*> canParamTypes;
@@ -619,7 +632,7 @@ Type* FuncType::_createCanonicalTypeOverride()
     FuncType* canType = getASTBuilder()->create<FuncType>();
     canType->resultType = canResultType;
     canType->paramTypes = canParamTypes;
-
+    canType->errorType = canErrorType;
     return canType;
 }
 
@@ -634,6 +647,7 @@ HashCode FuncType::_getHashCodeOverride()
             hashCode,
             getParamType(pp)->getHashCode());
     }
+    combineHash(hashCode, getErrorType()->getHashCode());
     return hashCode;
 }