switch statement code gen.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@42616 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/CodeGen/CGStmt.cpp b/CodeGen/CGStmt.cpp
index f1f915e..2b9a72b 100644
--- a/CodeGen/CGStmt.cpp
+++ b/CodeGen/CGStmt.cpp
@@ -57,6 +57,9 @@
case Stmt::BreakStmtClass: EmitBreakStmt(); break;
case Stmt::ContinueStmtClass: EmitContinueStmt(); break;
+ case Stmt::SwitchStmtClass: EmitSwitchStmt(cast<SwitchStmt>(*S)); break;
+ case Stmt::DefaultStmtClass: EmitDefaultStmt(cast<DefaultStmt>(*S)); break;
+ case Stmt::CaseStmtClass: EmitCaseStmt(cast<CaseStmt>(*S)); break;
}
}
@@ -350,3 +353,50 @@
Builder.CreateBr(Block);
EmitBlock(new llvm::BasicBlock());
}
+
+void CodeGenFunction::EmitCaseStmt(const CaseStmt &S) {
+ StartBlock("sw.bb");
+ llvm::Value *V = EmitScalarExpr(S.getLHS());
+ SwitchInsn->addCase(cast<llvm::ConstantInt>(V), Builder.GetInsertBlock());
+ assert (!S.getRHS() && "Case statement range is not yet supported");
+ EmitStmt(S.getSubStmt());
+}
+
+void CodeGenFunction::EmitDefaultStmt(const DefaultStmt &S) {
+ StartBlock("sw.default");
+ // Current insert block is the default destination.
+ SwitchInsn->setSuccessor(0, Builder.GetInsertBlock());
+ EmitStmt(S.getSubStmt());
+}
+
+void CodeGenFunction::EmitSwitchStmt(const SwitchStmt &S) {
+ llvm::Value *CondV = EmitScalarExpr(S.getCond());
+
+ // Handle nested switch statements.
+ llvm::SwitchInst *SavedSwitchInsn = SwitchInsn;
+
+ // Create basic block to hold stuff that comes after switch statement.
+ // Initially use it to hold DefaultStmt.
+ llvm::BasicBlock *NextBlock = new llvm::BasicBlock("after.sw", CurFn);
+ SwitchInsn = Builder.CreateSwitch(CondV, NextBlock);
+
+ // All break statements jump to NextBlock. If BreakContinueStack is non empty then
+ // reuse last ContinueBlock.
+ llvm::BasicBlock *ContinueBlock = NULL;
+ if (!BreakContinueStack.empty())
+ ContinueBlock = BreakContinueStack.back().ContinueBlock;
+ BreakContinueStack.push_back(BreakContinue(NextBlock, ContinueBlock));
+
+ // Emit switch body.
+ EmitStmt(S.getBody());
+ BreakContinueStack.pop_back();
+
+ // Prune insert block if it is dummy.
+ llvm::BasicBlock *BB = Builder.GetInsertBlock();
+ if (isDummyBlock(BB))
+ BB->eraseFromParent();
+
+ // Place NextBlock as the new insert point.
+ Builder.SetInsertPoint(NextBlock);
+ SwitchInsn = SavedSwitchInsn;
+}