Add semantic analysis for "blocks".
Highlights...
- 4 new AST nodes, BlockExpr, BlockStmtExpr, BlockExprExpr, BlockDeclRefExpr.
- Sema::ActOnBlockStart(), ActOnBlockError(), ActOnBlockStmtExpr(), ActOnBlockExprExpr(), ActOnBlockReturnStmt().
Next steps...
- hack Sema::ActOnIdentifierExpr() to deal with block decl refs.
- add attribute handler for byref decls.
- add test cases.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@55710 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaStmt.cpp b/lib/Sema/SemaStmt.cpp
index 629ab34..98efc8a 100644
--- a/lib/Sema/SemaStmt.cpp
+++ b/lib/Sema/SemaStmt.cpp
@@ -588,6 +588,10 @@
Action::StmtResult
Sema::ActOnGotoStmt(SourceLocation GotoLoc, SourceLocation LabelLoc,
IdentifierInfo *LabelII) {
+ // If we are in a block, reject all gotos for now.
+ if (CurBlock)
+ return Diag(GotoLoc, diag::err_goto_in_block);
+
// Look up the record for this label identifier.
LabelStmt *&LabelDecl = LabelMap[LabelII];
@@ -630,10 +634,61 @@
return new BreakStmt(BreakLoc);
}
+/// ActOnBlockReturnStmt - Utilty routine to figure out block's return type.
+///
+Action::StmtResult
+Sema::ActOnBlockReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) {
+
+ // If this is the first return we've seen in the block, infer the type of
+ // the block from it.
+ if (CurBlock->ReturnType == 0) {
+ if (RetValExp)
+ CurBlock->ReturnType = RetValExp->getType().getTypePtr();
+ else
+ CurBlock->ReturnType = Context.VoidTy.getTypePtr();
+ return new ReturnStmt(ReturnLoc, RetValExp);
+ }
+
+ // Otherwise, verify that this result type matches the previous one. We are
+ // pickier with blocks than for normal functions because we don't have GCC
+ // compatibility to worry about here.
+ if (CurBlock->ReturnType->isVoidType()) {
+ if (RetValExp) {
+ Diag(ReturnLoc, diag::err_return_block_has_expr);
+ delete RetValExp;
+ RetValExp = 0;
+ }
+ return new ReturnStmt(ReturnLoc, RetValExp);
+ }
+
+ if (!RetValExp) {
+ Diag(ReturnLoc, diag::err_block_return_missing_expr);
+ return true;
+ }
+
+ // we have a non-void block with an expression, continue checking
+ QualType RetValType = RetValExp->getType();
+
+ // For now, restrict multiple return statements in a block to have
+ // strict compatible types only.
+ QualType BlockQT = QualType(CurBlock->ReturnType, 0);
+ if (Context.getCanonicalType(BlockQT).getTypePtr()
+ != Context.getCanonicalType(RetValType).getTypePtr()) {
+ DiagnoseAssignmentResult(Incompatible, ReturnLoc, BlockQT,
+ RetValType, RetValExp, "returning");
+ return true;
+ }
+
+ if (RetValExp) CheckReturnStackAddr(RetValExp, BlockQT, ReturnLoc);
+
+ return new ReturnStmt(ReturnLoc, (Expr*)RetValExp);
+}
Action::StmtResult
Sema::ActOnReturnStmt(SourceLocation ReturnLoc, ExprTy *rex) {
Expr *RetValExp = static_cast<Expr *>(rex);
+ if (CurBlock)
+ return ActOnBlockReturnStmt(ReturnLoc, RetValExp);
QualType FnRetType =
getCurFunctionDecl() ? getCurFunctionDecl()->getResultType() :
getCurMethodDecl()->getResultType();