package compiler import ( "tinygo.org/x/go-llvm" ) // This file contains helper functions for LLVM that are not exposed in the Go // bindings. // Return a list of values (actually, instructions) where this value is used as // an operand. func getUses(value llvm.Value) []llvm.Value { if value.IsNil() { return nil } var uses []llvm.Value use := value.FirstUse() for !use.IsNil() { uses = append(uses, use.User()) use = use.NextUse() } return uses } // splitBasicBlock splits a LLVM basic block into two parts. All instructions // after afterInst are moved into a new basic block (created right after the // current one) with the given name. func (c *Compiler) splitBasicBlock(afterInst llvm.Value, insertAfter llvm.BasicBlock, name string) llvm.BasicBlock { oldBlock := afterInst.InstructionParent() newBlock := c.ctx.InsertBasicBlock(insertAfter, name) var nextInstructions []llvm.Value // values to move // Collect to-be-moved instructions. inst := afterInst for { inst = llvm.NextInstruction(inst) if inst.IsNil() { break } nextInstructions = append(nextInstructions, inst) } // Move instructions. c.builder.SetInsertPointAtEnd(newBlock) for _, inst := range nextInstructions { inst.RemoveFromParentAsInstruction() c.builder.Insert(inst) } // Find PHI nodes to update. var phiNodes []llvm.Value // PHI nodes to update for bb := insertAfter.Parent().FirstBasicBlock(); !bb.IsNil(); bb = llvm.NextBasicBlock(bb) { for inst := bb.FirstInstruction(); !inst.IsNil(); inst = llvm.NextInstruction(inst) { if inst.IsAPHINode().IsNil() { continue } needsUpdate := false incomingCount := inst.IncomingCount() for i := 0; i < incomingCount; i++ { if inst.IncomingBlock(i) == oldBlock { needsUpdate = true break } } if !needsUpdate { // PHI node has no incoming edge from the old block. continue } phiNodes = append(phiNodes, inst) } } // Update PHI nodes. for _, phi := range phiNodes { c.builder.SetInsertPointBefore(phi) newPhi := c.builder.CreatePHI(phi.Type(), "") incomingCount := phi.IncomingCount() incomingVals := make([]llvm.Value, incomingCount) incomingBlocks := make([]llvm.BasicBlock, incomingCount) for i := 0; i < incomingCount; i++ { value := phi.IncomingValue(i) block := phi.IncomingBlock(i) if block == oldBlock { block = newBlock } incomingVals[i] = value incomingBlocks[i] = block } newPhi.AddIncoming(incomingVals, incomingBlocks) phi.ReplaceAllUsesWith(newPhi) phi.EraseFromParentAsInstruction() } return newBlock }