Golang llvm.InsertBasicBlock函数代码示例

func (c *compiler) VisitIfStmt(stmt *ast.IfStmt) {
	currBlock := c.builder.GetInsertBlock()
	resumeBlock := llvm.AddBasicBlock(currBlock.Parent(), "endif")
	resumeBlock.MoveAfter(currBlock)
	defer c.builder.SetInsertPointAtEnd(resumeBlock)

	var ifBlock, elseBlock llvm.BasicBlock
	if stmt.Else != nil {
		elseBlock = llvm.InsertBasicBlock(resumeBlock, "else")
		ifBlock = llvm.InsertBasicBlock(elseBlock, "if")
	} else {
		ifBlock = llvm.InsertBasicBlock(resumeBlock, "if")
	}
	if stmt.Else == nil {
		elseBlock = resumeBlock
	}

	if stmt.Init != nil {
		c.VisitStmt(stmt.Init)
	}

	cond_val := c.VisitExpr(stmt.Cond)
	c.builder.CreateCondBr(cond_val.LLVMValue(), ifBlock, elseBlock)
	c.builder.SetInsertPointAtEnd(ifBlock)
	c.VisitBlockStmt(stmt.Body, false)
	c.maybeImplicitBranch(resumeBlock)

	if stmt.Else != nil {
		c.builder.SetInsertPointAtEnd(elseBlock)
		c.VisitStmt(stmt.Else)
		c.maybeImplicitBranch(resumeBlock)
	}
}

// convertI2V converts an interface to a value.
func (v *LLVMValue) convertI2V(typ types.Type) (result, success Value) {
	builder := v.compiler.builder
	predicate := v.interfaceTypeEquals(typ).LLVMValue()

	// If result is zero, then we've got a match.
	end := llvm.InsertBasicBlock(builder.GetInsertBlock(), "end")
	end.MoveAfter(builder.GetInsertBlock())
	nonmatch := llvm.InsertBasicBlock(end, "nonmatch")
	match := llvm.InsertBasicBlock(nonmatch, "match")
	builder.CreateCondBr(predicate, match, nonmatch)

	builder.SetInsertPointAtEnd(match)
	matchResultValue := v.loadI2V(typ).LLVMValue()
	builder.CreateBr(end)

	builder.SetInsertPointAtEnd(nonmatch)
	nonmatchResultValue := llvm.ConstNull(matchResultValue.Type())
	builder.CreateBr(end)

	builder.SetInsertPointAtEnd(end)
	successValue := builder.CreatePHI(llvm.Int1Type(), "")
	resultValue := builder.CreatePHI(matchResultValue.Type(), "")

	successValues := []llvm.Value{llvm.ConstAllOnes(llvm.Int1Type()), llvm.ConstNull(llvm.Int1Type())}
	successBlocks := []llvm.BasicBlock{match, nonmatch}
	successValue.AddIncoming(successValues, successBlocks)
	success = v.compiler.NewValue(successValue, types.Typ[types.Bool])

	resultValues := []llvm.Value{matchResultValue, nonmatchResultValue}
	resultBlocks := []llvm.BasicBlock{match, nonmatch}
	resultValue.AddIncoming(resultValues, resultBlocks)
	result = v.compiler.NewValue(resultValue, typ)
	return result, success
}

func (lhs *LLVMValue) compareI2V(rhs *LLVMValue) Value {
	c := lhs.compiler
	predicate := lhs.interfaceTypeEquals(rhs.typ).LLVMValue()

	end := llvm.InsertBasicBlock(c.builder.GetInsertBlock(), "end")
	end.MoveAfter(c.builder.GetInsertBlock())
	nonmatch := llvm.InsertBasicBlock(end, "nonmatch")
	match := llvm.InsertBasicBlock(nonmatch, "match")
	c.builder.CreateCondBr(predicate, match, nonmatch)

	c.builder.SetInsertPointAtEnd(match)
	lhsValue := lhs.loadI2V(rhs.typ)
	matchResultValue := lhsValue.BinaryOp(token.EQL, rhs).LLVMValue()
	c.builder.CreateBr(end)

	c.builder.SetInsertPointAtEnd(nonmatch)
	nonmatchResultValue := llvm.ConstNull(llvm.Int1Type())
	c.builder.CreateBr(end)

	c.builder.SetInsertPointAtEnd(end)
	resultValue := c.builder.CreatePHI(matchResultValue.Type(), "")
	resultValues := []llvm.Value{matchResultValue, nonmatchResultValue}
	resultBlocks := []llvm.BasicBlock{match, nonmatch}
	resultValue.AddIncoming(resultValues, resultBlocks)
	return c.NewValue(resultValue, types.Typ[types.Bool])
}

func (c *compiler) VisitBlockStmt(stmt *ast.BlockStmt, createNewBlock bool) {
	// This is a little awkward, but it makes dealing with branching easier.
	// A free-standing block statement (i.e. one not attached to a control
	// statement) will splice in a new block.
	var doneBlock llvm.BasicBlock
	if createNewBlock {
		currBlock := c.builder.GetInsertBlock()
		doneBlock = llvm.InsertBasicBlock(currBlock, "")
		doneBlock.MoveAfter(currBlock)
		newBlock := llvm.InsertBasicBlock(doneBlock, "")
		c.builder.CreateBr(newBlock)
		c.builder.SetInsertPointAtEnd(newBlock)
	}

	for _, stmt := range stmt.List {
		c.VisitStmt(stmt)
		if _, ok := stmt.(*ast.BranchStmt); ok {
			// Ignore anything after a branch statement.
			break
		}
	}

	if createNewBlock {
		c.maybeImplicitBranch(doneBlock)
		c.builder.SetInsertPointAtEnd(doneBlock)
	}
}

func (c *compiler) VisitBlockStmt(stmt *ast.BlockStmt, createNewBlock bool) {
	// This is a little awkward, but it makes dealing with branching easier.
	// A free-standing block statement (i.e. one not attached to a control
	// statement) will splice in a new block.
	var doneBlock llvm.BasicBlock
	if createNewBlock {
		currBlock := c.builder.GetInsertBlock()
		doneBlock = llvm.InsertBasicBlock(currBlock, "")
		doneBlock.MoveAfter(currBlock)
		newBlock := llvm.InsertBasicBlock(doneBlock, "")
		c.builder.CreateBr(newBlock)
		c.builder.SetInsertPointAtEnd(newBlock)
	}

	// Visit each statement in the block. When we have a terminator,
	// ignore everything until we get to a labeled statement.
	for _, stmt := range stmt.List {
		currBlock := c.builder.GetInsertBlock()
		in := currBlock.LastInstruction()
		if in.IsNil() || in.IsATerminatorInst().IsNil() {
			c.VisitStmt(stmt)
		} else if _, ok := stmt.(*ast.LabeledStmt); ok {
			// FIXME we might end up with a labeled statement
			// with no predecessors, due to dead code elimination.
			c.VisitStmt(stmt)
		}
	}

	if createNewBlock {
		c.maybeImplicitBranch(doneBlock)
		c.builder.SetInsertPointAtEnd(doneBlock)
	}
}

// Binary logical operators are handled specially, outside of the Value
// type, because of the need to perform lazy evaluation.
//
// Binary logical operators are implemented using a Phi node, which takes
// on the appropriate value depending on which basic blocks branch to it.
func (c *compiler) compileLogicalOp(op token.Token, lhs Value, rhsFunc func() Value) Value {
	lhsBlock := c.builder.GetInsertBlock()
	resultBlock := llvm.AddBasicBlock(lhsBlock.Parent(), "")
	resultBlock.MoveAfter(lhsBlock)
	rhsBlock := llvm.InsertBasicBlock(resultBlock, "")
	falseBlock := llvm.InsertBasicBlock(resultBlock, "")

	if op == token.LOR {
		c.builder.CreateCondBr(lhs.LLVMValue(), resultBlock, rhsBlock)
	} else {
		c.builder.CreateCondBr(lhs.LLVMValue(), rhsBlock, falseBlock)
	}
	c.builder.SetInsertPointAtEnd(rhsBlock)
	rhs := rhsFunc()
	rhsBlock = c.builder.GetInsertBlock() // rhsFunc may create blocks
	c.builder.CreateCondBr(rhs.LLVMValue(), resultBlock, falseBlock)
	c.builder.SetInsertPointAtEnd(falseBlock)
	c.builder.CreateBr(resultBlock)
	c.builder.SetInsertPointAtEnd(resultBlock)

	result := c.builder.CreatePHI(llvm.Int1Type(), "")
	trueValue := llvm.ConstAllOnes(llvm.Int1Type())
	falseValue := llvm.ConstNull(llvm.Int1Type())
	var values []llvm.Value
	var blocks []llvm.BasicBlock
	if op == token.LOR {
		values = []llvm.Value{trueValue, trueValue, falseValue}
		blocks = []llvm.BasicBlock{lhsBlock, rhsBlock, falseBlock}
	} else {
		values = []llvm.Value{trueValue, falseValue}
		blocks = []llvm.BasicBlock{rhsBlock, falseBlock}
	}
	result.AddIncoming(values, blocks)
	return c.NewLLVMValue(result, types.Bool)
}

func (c *compiler) VisitForStmt(stmt *ast.ForStmt) {
	currBlock := c.builder.GetInsertBlock()
	doneBlock := llvm.AddBasicBlock(currBlock.Parent(), "done")
	doneBlock.MoveAfter(currBlock)
	loopBlock := llvm.InsertBasicBlock(doneBlock, "loop")
	defer c.builder.SetInsertPointAtEnd(doneBlock)

	condBlock := loopBlock
	if stmt.Cond != nil {
		condBlock = llvm.InsertBasicBlock(loopBlock, "cond")
	}

	postBlock := condBlock
	if stmt.Post != nil {
		postBlock = llvm.InsertBasicBlock(doneBlock, "post")
	}

	if c.lastlabel != nil {
		labelData := c.labelData(c.lastlabel)
		labelData.Break = doneBlock
		labelData.Continue = postBlock
		c.lastlabel = nil
	}

	c.breakblocks = append(c.breakblocks, doneBlock)
	c.continueblocks = append(c.continueblocks, postBlock)
	defer func() {
		c.breakblocks = c.breakblocks[:len(c.breakblocks)-1]
		c.continueblocks = c.continueblocks[:len(c.continueblocks)-1]
	}()

	// Is there an initializer? Create a new scope and visit the statement.
	if stmt.Init != nil {
		c.VisitStmt(stmt.Init)
	}

	// Start the loop.
	if stmt.Cond != nil {
		c.builder.CreateBr(condBlock)
		c.builder.SetInsertPointAtEnd(condBlock)
		condVal := c.VisitExpr(stmt.Cond)
		c.builder.CreateCondBr(condVal.LLVMValue(), loopBlock, doneBlock)
	} else {
		c.builder.CreateBr(loopBlock)
	}

	// Post.
	if stmt.Post != nil {
		c.builder.SetInsertPointAtEnd(postBlock)
		c.VisitStmt(stmt.Post)
		c.builder.CreateBr(condBlock)
	}

	// Loop body.
	c.builder.SetInsertPointAtEnd(loopBlock)
	c.VisitBlockStmt(stmt.Body, false)
	c.maybeImplicitBranch(postBlock)
}

func (v *LLVMValue) mustConvertI2V(typ types.Type) Value {
	result, ok := v.convertI2V(typ)

	c, builder := v.compiler, v.compiler.builder
	end := llvm.InsertBasicBlock(builder.GetInsertBlock(), "end")
	end.MoveAfter(builder.GetInsertBlock())
	failed := llvm.InsertBasicBlock(end, "failed")
	builder.CreateCondBr(ok.LLVMValue(), end, failed)
	builder.SetInsertPointAtEnd(failed)

	s := fmt.Sprintf("convertI2V(%s, %s) failed", v.typ, typ)
	c.visitPanic(c.NewConstValue(exact.MakeString(s), types.Typ[types.String]))
	builder.SetInsertPointAtEnd(end)
	return result
}

func (v *LLVMValue) mustConvertI2I(iface *types.Interface) Value {
	result, ok := v.convertI2I(iface)

	c, builder := v.compiler, v.compiler.builder
	end := llvm.InsertBasicBlock(builder.GetInsertBlock(), "end")
	end.MoveAfter(builder.GetInsertBlock())
	failed := llvm.InsertBasicBlock(end, "failed")
	builder.CreateCondBr(ok.LLVMValue(), end, failed)
	builder.SetInsertPointAtEnd(failed)

	s := fmt.Sprintf("convertI2I(%s, %s) failed", v.typ, iface)
	c.visitPanic(c.NewConstValue(token.STRING, strconv.Quote(s)))
	builder.SetInsertPointAtEnd(end)
	return result
}

func (c *compiler) VisitIfStmt(stmt *ast.IfStmt) {
	curr_block := c.builder.GetInsertBlock()
	resume_block := llvm.AddBasicBlock(curr_block.Parent(), "endif")
	resume_block.MoveAfter(curr_block)

	var if_block, else_block llvm.BasicBlock
	if stmt.Else != nil {
		else_block = llvm.InsertBasicBlock(resume_block, "else")
		if_block = llvm.InsertBasicBlock(else_block, "if")
	} else {
		if_block = llvm.InsertBasicBlock(resume_block, "if")
	}
	if stmt.Else == nil {
		else_block = resume_block
	}

	if stmt.Init != nil {
		c.PushScope()
		c.VisitStmt(stmt.Init)
		defer c.PopScope()
	}

	cond_val := c.VisitExpr(stmt.Cond)
	c.builder.CreateCondBr(cond_val.LLVMValue(), if_block, else_block)
	c.builder.SetInsertPointAtEnd(if_block)
	c.VisitBlockStmt(stmt.Body)
	if in := if_block.LastInstruction(); in.IsNil() || in.IsATerminatorInst().IsNil() {
		c.builder.CreateBr(resume_block)
	}

	if stmt.Else != nil {
		c.builder.SetInsertPointAtEnd(else_block)
		c.VisitStmt(stmt.Else)
		if in := else_block.LastInstruction(); in.IsNil() || in.IsATerminatorInst().IsNil() {
			c.builder.CreateBr(resume_block)
		}
	}

	// If there's a block after the "resume" block (i.e. a nested control
	// statement), then create a branch to it as the last instruction.
	c.builder.SetInsertPointAtEnd(resume_block)
	if last := resume_block.Parent().LastBasicBlock(); last != resume_block {
		c.builder.CreateBr(last)
		c.builder.SetInsertPointBefore(resume_block.FirstInstruction())
	}
}

func (c *compiler) VisitForStmt(stmt *ast.ForStmt) {
	currBlock := c.builder.GetInsertBlock()
	doneBlock := llvm.AddBasicBlock(currBlock.Parent(), "done")
	doneBlock.MoveAfter(currBlock)
	loopBlock := llvm.InsertBasicBlock(doneBlock, "loop")
	defer c.builder.SetInsertPointAtEnd(doneBlock)

	condBlock := loopBlock
	if stmt.Cond != nil {
		condBlock = llvm.InsertBasicBlock(loopBlock, "cond")
	}

	postBlock := condBlock
	if stmt.Post != nil {
		postBlock = llvm.InsertBasicBlock(doneBlock, "post")
	}

	// Is there an initializer? Create a new scope and visit the statement.
	if stmt.Init != nil {
		c.PushScope()
		c.VisitStmt(stmt.Init)
		defer c.PopScope()
	}

	// Start the loop.
	if stmt.Cond != nil {
		c.builder.CreateBr(condBlock)
		c.builder.SetInsertPointAtEnd(condBlock)
		condVal := c.VisitExpr(stmt.Cond)
		c.builder.CreateCondBr(condVal.LLVMValue(), loopBlock, doneBlock)
	} else {
		c.builder.CreateBr(loopBlock)
	}

	// Post.
	if stmt.Post != nil {
		c.builder.SetInsertPointAtEnd(postBlock)
		c.VisitStmt(stmt.Post)
		c.builder.CreateBr(condBlock)
	}

	// Loop body.
	c.builder.SetInsertPointAtEnd(loopBlock)
	c.VisitBlockStmt(stmt.Body)
	c.maybeImplicitBranch(postBlock)
}

// convertI2V converts an interface to a value.
func (v *LLVMValue) convertI2V(typ types.Type) (result, success Value) {
	typptrType := llvm.PointerType(llvm.Int8Type(), 0)
	runtimeType := v.compiler.types.ToRuntime(typ)
	runtimeType = llvm.ConstBitCast(runtimeType, typptrType)
	vval := v.LLVMValue()

	builder := v.compiler.builder
	ifaceType := builder.CreateExtractValue(vval, 0, "")
	diff := builder.CreatePtrDiff(runtimeType, ifaceType, "")
	zero := llvm.ConstNull(diff.Type())
	predicate := builder.CreateICmp(llvm.IntEQ, diff, zero, "")

	// If result is zero, then we've got a match.
	end := llvm.InsertBasicBlock(builder.GetInsertBlock(), "end")
	end.MoveAfter(builder.GetInsertBlock())
	nonmatch := llvm.InsertBasicBlock(end, "nonmatch")
	match := llvm.InsertBasicBlock(nonmatch, "match")
	builder.CreateCondBr(predicate, match, nonmatch)

	builder.SetInsertPointAtEnd(match)
	matchResultValue := v.loadI2V(typ).LLVMValue()
	builder.CreateBr(end)

	builder.SetInsertPointAtEnd(nonmatch)
	nonmatchResultValue := llvm.ConstNull(matchResultValue.Type())
	builder.CreateBr(end)

	builder.SetInsertPointAtEnd(end)
	successValue := builder.CreatePHI(llvm.Int1Type(), "")
	resultValue := builder.CreatePHI(matchResultValue.Type(), "")

	successValues := []llvm.Value{llvm.ConstAllOnes(llvm.Int1Type()), llvm.ConstNull(llvm.Int1Type())}
	successBlocks := []llvm.BasicBlock{match, nonmatch}
	successValue.AddIncoming(successValues, successBlocks)
	success = v.compiler.NewLLVMValue(successValue, types.Bool)

	resultValues := []llvm.Value{matchResultValue, nonmatchResultValue}
	resultBlocks := []llvm.BasicBlock{match, nonmatch}
	resultValue.AddIncoming(resultValues, resultBlocks)
	result = v.compiler.NewLLVMValue(resultValue, typ)
	return result, success
}

func (c *compiler) getBoolString(v llvm.Value) llvm.Value {
	startBlock := c.builder.GetInsertBlock()
	resultBlock := llvm.InsertBasicBlock(startBlock, "")
	resultBlock.MoveAfter(startBlock)
	falseBlock := llvm.InsertBasicBlock(resultBlock, "")

	CharPtr := llvm.PointerType(llvm.Int8Type(), 0)
	falseString := c.builder.CreateGlobalStringPtr("false", "")
	falseString = c.builder.CreateBitCast(falseString, CharPtr, "")
	trueString := c.builder.CreateGlobalStringPtr("true", "")
	trueString = c.builder.CreateBitCast(trueString, CharPtr, "")

	c.builder.CreateCondBr(v, resultBlock, falseBlock)
	c.builder.SetInsertPointAtEnd(falseBlock)
	c.builder.CreateBr(resultBlock)
	c.builder.SetInsertPointAtEnd(resultBlock)
	result := c.builder.CreatePHI(CharPtr, "")
	result.AddIncoming([]llvm.Value{trueString, falseString},
		[]llvm.BasicBlock{startBlock, falseBlock})
	return result
}

// convertI2V converts an interface to a value.
func (v *LLVMValue) convertI2V(typ types.Type) Value {
	typptrType := llvm.PointerType(llvm.Int8Type(), 0)
	runtimeType := v.compiler.types.ToRuntime(typ)
	runtimeType = llvm.ConstBitCast(runtimeType, typptrType)
	vptr := v.pointer.LLVMValue()

	builder := v.compiler.builder
	ifaceType := builder.CreateLoad(builder.CreateStructGEP(vptr, 1, ""), "")
	diff := builder.CreatePtrDiff(runtimeType, ifaceType, "")
	zero := llvm.ConstNull(diff.Type())
	predicate := builder.CreateICmp(llvm.IntEQ, diff, zero, "")
	llvmtype := v.compiler.types.ToLLVM(typ)
	result := builder.CreateAlloca(llvmtype, "")

	// If result is zero, then we've got a match.
	end := llvm.InsertBasicBlock(builder.GetInsertBlock(), "end")
	end.MoveAfter(builder.GetInsertBlock())
	nonmatch := llvm.InsertBasicBlock(end, "nonmatch")
	match := llvm.InsertBasicBlock(nonmatch, "match")
	builder.CreateCondBr(predicate, match, nonmatch)

	builder.SetInsertPointAtEnd(match)
	value := builder.CreateLoad(builder.CreateStructGEP(vptr, 0, ""), "")
	value = builder.CreateBitCast(value, result.Type(), "")
	value = builder.CreateLoad(value, "")
	builder.CreateStore(value, result)
	builder.CreateBr(end)

	// TODO should return {value, ok}
	builder.SetInsertPointAtEnd(nonmatch)
	builder.CreateStore(llvm.ConstNull(llvmtype), result)
	builder.CreateBr(end)

	//builder.SetInsertPointAtEnd(end)
	result = builder.CreateLoad(result, "")
	return v.compiler.NewLLVMValue(result, typ)
}

func (c *compiler) VisitRangeStmt(stmt *ast.RangeStmt) {
	currBlock := c.builder.GetInsertBlock()
	doneBlock := llvm.AddBasicBlock(currBlock.Parent(), "done")
	doneBlock.MoveAfter(currBlock)
	postBlock := llvm.InsertBasicBlock(doneBlock, "post")
	loopBlock := llvm.InsertBasicBlock(postBlock, "loop")
	condBlock := llvm.InsertBasicBlock(loopBlock, "cond")
	defer c.builder.SetInsertPointAtEnd(doneBlock)

	// Evaluate range expression first.
	x := c.VisitExpr(stmt.X)

	// If it's a pointer type, we'll first check that it's non-nil.
	typ := types.Underlying(x.Type())
	if _, ok := typ.(*types.Pointer); ok {
		ifBlock := llvm.InsertBasicBlock(doneBlock, "if")
		isnotnull := c.builder.CreateIsNotNull(x.LLVMValue(), "")
		c.builder.CreateCondBr(isnotnull, ifBlock, doneBlock)
		c.builder.SetInsertPointAtEnd(ifBlock)
	}

	// Is it a new var definition? Then allocate some memory on the stack.
	var keyType, valueType types.Type
	var keyPtr, valuePtr llvm.Value
	if stmt.Tok == token.DEFINE {
		if key := stmt.Key.(*ast.Ident); key.Name != "_" {
			keyType = key.Obj.Type.(types.Type)
			keyPtr = c.builder.CreateAlloca(c.types.ToLLVM(keyType), "")
			key.Obj.Data = c.NewLLVMValue(keyPtr, &types.Pointer{Base: keyType}).makePointee()
		}
		if stmt.Value != nil {
			if value := stmt.Value.(*ast.Ident); value.Name != "_" {
				valueType = value.Obj.Type.(types.Type)
				valuePtr = c.builder.CreateAlloca(c.types.ToLLVM(valueType), "")
				value.Obj.Data = c.NewLLVMValue(valuePtr, &types.Pointer{Base: valueType}).makePointee()
			}
		}
	}

	c.breakblocks = append(c.breakblocks, doneBlock)
	c.continueblocks = append(c.continueblocks, postBlock)
	defer func() {
		c.breakblocks = c.breakblocks[:len(c.breakblocks)-1]
		c.continueblocks = c.continueblocks[:len(c.continueblocks)-1]
	}()

	isarray := false
	var base, length llvm.Value
	_, isptr := typ.(*types.Pointer)
	if isptr {
		typ = typ.(*types.Pointer).Base
	}
	switch typ := types.Underlying(typ).(type) {
	case *types.Map:
		goto maprange
	case *types.Name:
		stringvalue := x.LLVMValue()
		length = c.builder.CreateExtractValue(stringvalue, 1, "")
		goto stringrange
	case *types.Array:
		isarray = true
		x := x
		if !isptr {
			if x_, ok := x.(*LLVMValue); ok && x_.pointer != nil {
				x = x_.pointer
			} else {
				// TODO load value onto stack for indexing?
			}
		}
		base = x.LLVMValue()
		length = llvm.ConstInt(llvm.Int32Type(), typ.Len, false)
		goto arrayrange
	case *types.Slice:
		slicevalue := x.LLVMValue()
		base = c.builder.CreateExtractValue(slicevalue, 0, "")
		length = c.builder.CreateExtractValue(slicevalue, 1, "")
		goto arrayrange
	}

maprange:
	{
		currBlock = c.builder.GetInsertBlock()
		c.builder.CreateBr(condBlock)
		c.builder.SetInsertPointAtEnd(condBlock)
		nextptrphi := c.builder.CreatePHI(c.target.IntPtrType(), "next")
		nextptr, pk, pv := c.mapNext(x.(*LLVMValue), nextptrphi)
		notnull := c.builder.CreateIsNotNull(nextptr, "")
		c.builder.CreateCondBr(notnull, loopBlock, doneBlock)
		c.builder.SetInsertPointAtEnd(loopBlock)
		if !keyPtr.IsNil() {
			keyval := c.builder.CreateLoad(pk, "")
			c.builder.CreateStore(keyval, keyPtr)
		}
		if !valuePtr.IsNil() {
			valval := c.builder.CreateLoad(pv, "")
			c.builder.CreateStore(valval, valuePtr)
		}
		c.VisitBlockStmt(stmt.Body, false)
		c.maybeImplicitBranch(postBlock)
		c.builder.SetInsertPointAtEnd(postBlock)
//.........这里部分代码省略.........