llgo/ssa: DeferAlways/DeferInCond/DeferInLoop

cl/compile.go

@@ -148,8 +148,11 @@ type context struct {
 	loaded map[*types.Package]*pkgInfo // loaded packages
 	bvals  map[ssa.Value]llssa.Expr    // block values
 	vargs  map[*ssa.Alloc][]llssa.Expr // varargs
-	inits  []func()
-	phis   []func()
+
+	blkInfos []blockInfo
+
+	inits []func()
+	phis  []func()
 }
 
 func (p *context) inMain(instr ssa.Instruction) bool {
@@ -277,10 +280,16 @@ func (p *context) compileFuncDecl(pkg llssa.Package, f *ssa.Function) (llssa.Fun
 			for i, block := range f.Blocks {
 				off[i] = p.compilePhis(b, block)
 			}
-			for i, block := range f.Blocks {
+			p.blkInfos = blockInfos(f.Blocks)
+			i := 0
+			for {
+				block := f.Blocks[i]
 				doMainInit := (i == 0 && name == "main")
 				doModInit := (i == 1 && f.Name() == "init" && sig.Recv() == nil)
 				p.compileBlock(b, block, off[i], doMainInit, doModInit)
+				if i = p.blkInfos[i].next; i < 0 {
+					break
+				}
 			}
 			for _, phi := range p.phis {
 				phi()
@@ -291,6 +300,24 @@ func (p *context) compileFuncDecl(pkg llssa.Package, f *ssa.Function) (llssa.Fun
 	return fn, nil, goFunc
 }
 
+type blockInfo struct {
+	kind llssa.DoAction
+	next int
+}
+
+func blockInfos(blks []*ssa.BasicBlock) []blockInfo {
+	n := len(blks)
+	infos := make([]blockInfo, n)
+	for i := range blks {
+		next := i + 1
+		if next >= n {
+			next = -1
+		}
+		infos[i] = blockInfo{kind: llssa.DeferInCond, next: next}
+	}
+	return infos
+}
+
 // funcOf returns a function by name and set ftype = goFunc, cFunc, etc.
 // or returns nil and set ftype = llgoCstr, llgoAlloca, llgoUnreachable, etc.
 func (p *context) funcOf(fn *ssa.Function) (aFn llssa.Function, pyFn llssa.PyObjRef, ftype int) {
@@ -516,7 +543,7 @@ func (p *context) compilePhis(b llssa.Builder, block *ssa.BasicBlock) int {
 			for n < ninstr && isPhi(block.Instrs[n]) {
 				n++
 			}
-			rets := make([]llssa.Expr, n)
+			rets := make([]llssa.Expr, n) // TODO(xsw): check to remove this
 			for i := 0; i < n; i++ {
 				iv := block.Instrs[i].(*ssa.Phi)
 				rets[i] = p.compilePhi(b, iv)
@@ -798,7 +825,7 @@ func (p *context) compileInstr(b llssa.Builder, instr ssa.Instruction) {
 		val := p.compileValue(b, v.Value)
 		b.MapUpdate(m, key, val)
 	case *ssa.Defer:
-		p.call(b, llssa.Defer, &v.Call)
+		p.call(b, p.blkInfos[v.Block().Index].kind, &v.Call)
 	case *ssa.Go:
 		p.call(b, llssa.Go, &v.Call)
 	case *ssa.RunDefers: