func (v *allocator) allocate(fn *ssa.Function) {
for _, par := range fn.Parameters() {
v.allocateValue(par)
}
for _, block := range fn.Blocks() {
for _, instr := range block.Instrs() {
if val, ok := instr.(ssa.Value); ok {
v.allocateValue(val)
}
}
}
}
func (v *CFG) construct(fn *ssa.Function) {
blocks := fn.Blocks()
nodes := make([]*CFGNode, len(blocks))
blocksToNodes := make(map[*ssa.Block]*CFGNode)
for i, block := range blocks {
nodes[i] = &CFGNode{
block: block,
}
blocksToNodes[block] = nodes[i]
}
for _, node := range nodes {
switch term := node.block.LastInstr().(type) {
case *ssa.Br:
ops := ssa.GetOperands(term)
node.next = []*CFGNode{
blocksToNodes[ops[0].(*ssa.Block)],
}
case *ssa.CondBr:
ops := ssa.GetOperands(term)
node.next = []*CFGNode{
blocksToNodes[ops[1].(*ssa.Block)],
blocksToNodes[ops[2].(*ssa.Block)],
}
case *ssa.Unreachable, *ssa.Ret:
// these lead to nowhere
default:
panic("unimplemented terminating instruction")
}
for _, next := range node.next {
next.prev = append(next.prev, node)
}
}
v.nodes = nodes
}
func (v Target) genSaveFunctionParameters(a *allocator, fn *ssa.Function) {
var vals []ssa.Value
for _, par := range fn.Parameters() {
vals = append(vals, par)
}
if v.Platform.IsUnixLike() {
v.sysVCopyFunctionVals(a, vals, fn.Type().(*types.Signature), false)
} else if v.Platform == platform.Windows {
v.winSaveFunctionParameters(a, vals, fn.Type().(*types.Signature))
} else {
panic("unim")
}
}
func (v *Target) genFunction(fn *ssa.Function) {
if fn.IsPrototype() {
return
}
allocator := newAllocator()
allocator.allocate(fn)
blockLabelMap := make(map[*ssa.Block]string)
for _, block := range fn.Blocks() {
blockLabelMap[block] = v.nextLabelName()
}
v.wnl()
v.wop(".globl %s", fn.Name())
v.wop(".align 16, 0x90") // pad with NOPs
if v.Platform.IsUnixLike() {
v.wop(".type %s,@function", fn.Name())
}
v.wlabel(fn.Name())
v.wop("pushq #rbp")
v.wop("pushq #rbx")
v.wop("pushq #r15")
v.wop("movq #rsp, #rbp")
v.wop("subq $%d, #rsp", (allocator.stackSize|0xF)+1)
retType := fn.Type().(*types.Signature).ReturnType()
if sysVClassifyType(retType)[0] == sysVClassMEMORY {
v.wop("movq #rdi, #r15")
} else if winIsMemory(retType) {
v.wop("movq #rdx, #r15")
}
v.genSaveFunctionParameters(allocator, fn)
for _, block := range fn.Blocks() {
v.wlabel(blockLabelMap[block])
for _, instr := range block.Instrs() {
v.genInstr(allocator, instr, blockLabelMap)
}
}
}