ssa: removes the deadcode on BasicBlock

internal/engine/wazevo/ssa/basic_block.go

@@ -49,21 +49,12 @@ type BasicBlock interface {
 	// ReturnBlock returns ture if this block represents the function return.
 	ReturnBlock() bool
 
-	// FormatHeader returns the debug string of this block, not including instruction.
-	FormatHeader(b Builder) string
-
 	// Valid is true if this block is still valid even after optimizations.
 	Valid() bool
 
 	// Sealed is true if this block has been sealed.
 	Sealed() bool
 
-	// BeginPredIterator returns the first predecessor of this block.
-	BeginPredIterator() BasicBlock
-
-	// NextPredIterator returns the next predecessor of this block.
-	NextPredIterator() BasicBlock
-
 	// Preds returns the number of predecessors of this block.
 	Preds() int
 
@@ -90,10 +81,9 @@ type (
 		rootInstr, currentInstr *Instruction
 		// params are Values that represent parameters to a basicBlock.
 		// Each parameter can be considered as an output of PHI instruction in traditional SSA.
-		params   []Value
-		predIter int
-		preds    []basicBlockPredecessorInfo
-		success  []*basicBlock
+		params  []Value
+		preds   []basicBlockPredecessorInfo
+		success []*basicBlock
 		// singlePred is the alias to preds[0] for fast lookup, and only set after Seal is called.
 		singlePred *basicBlock
 		// lastDefinitions maps Variable to its last definition in this block.
@@ -240,22 +230,6 @@ func (bb *basicBlock) NumPreds() int {
 	return len(bb.preds)
 }
 
-// BeginPredIterator implements BasicBlock.BeginPredIterator.
-func (bb *basicBlock) BeginPredIterator() BasicBlock {
-	bb.predIter = 0
-	return bb.NextPredIterator()
-}
-
-// NextPredIterator implements BasicBlock.NextPredIterator.
-func (bb *basicBlock) NextPredIterator() BasicBlock {
-	if bb.predIter >= len(bb.preds) {
-		return nil
-	}
-	pred := bb.preds[bb.predIter].blk
-	bb.predIter++
-	return pred
-}
-
 // Preds implements BasicBlock.Preds.
 func (bb *basicBlock) Preds() int {
 	return len(bb.preds)
@@ -327,8 +301,8 @@ func (bb *basicBlock) addPred(blk BasicBlock, branch *Instruction) {
 	pred.success = append(pred.success, bb)
 }
 
-// FormatHeader implements BasicBlock.FormatHeader.
-func (bb *basicBlock) FormatHeader(b Builder) string {
+// formatHeader returns the string representation of the header of the basicBlock.
+func (bb *basicBlock) formatHeader(b Builder) string {
 	ps := make([]string, len(bb.params))
 	for i, p := range bb.params {
 		ps[i] = p.formatWithType(b)

internal/engine/wazevo/ssa/builder.go

@@ -566,7 +566,7 @@ func (b *builder) Format() string {
 	}
 	for bb := iterBegin(); bb != nil; bb = iterNext() {
 		str.WriteByte('\n')
-		str.WriteString(bb.FormatHeader(b))
+		str.WriteString(bb.formatHeader(b))
 		str.WriteByte('\n')
 
 		for cur := bb.Root(); cur != nil; cur = cur.Next() {

internal/engine/wazevo/ssa/pass_blk_layouts.go

@@ -143,7 +143,7 @@ func passLayoutBlocks(b *builder) {
 	if wazevoapi.SSAValidationEnabled {
 		for _, trampoline := range trampolines {
 			if _, ok := b.blkVisited[trampoline]; !ok {
-				panic("BUG: trampoline block not inserted: " + trampoline.FormatHeader(b))
+				panic("BUG: trampoline block not inserted: " + trampoline.formatHeader(b))
 			}
 			trampoline.validate(b)
 		}