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
}
func (u *unit) defineFunction(f *ssa.Function) {
// Nothing to do for functions without bodies.
if len(f.Blocks) == 0 {
return
}
// Only define functions from this package.
if f.Pkg == nil {
if r := f.Signature.Recv(); r != nil {
if r.Pkg() != nil && r.Pkg() != u.pkg.Object {
return
} else if named, ok := r.Type().(*types.Named); ok && named.Obj().Parent() == types.Universe {
// This condition is true iff f is error.Error.
if u.pkg.Object.Path() != "runtime" {
return
}
}
}
} else if f.Pkg != u.pkg {
return
}
fr := frame{
unit: u,
blocks: make([]llvm.BasicBlock, len(f.Blocks)),
env: make(map[ssa.Value]*LLVMValue),
}
fr.logf("Define function: %s", f.String())
llvmFunction := fr.resolveFunction(f).LLVMValue()
delete(u.undefinedFuncs, f)
// Push the function onto the debug context.
// TODO(axw) create a fake CU for synthetic functions
if u.GenerateDebug && f.Synthetic == "" {
u.debug.pushFunctionContext(llvmFunction, f.Signature, f.Pos())
defer u.debug.popFunctionContext()
u.debug.setLocation(u.builder, f.Pos())
}
// Functions that call recover must not be inlined, or we
// can't tell whether the recover call is valid at runtime.
if f.Recover != nil {
llvmFunction.AddFunctionAttr(llvm.NoInlineAttribute)
}
for i, block := range f.Blocks {
fr.blocks[i] = llvm.AddBasicBlock(llvmFunction, fmt.Sprintf(".%d.%s", i, block.Comment))
}
fr.builder.SetInsertPointAtEnd(fr.blocks[0])
var paramOffset int
if len(f.FreeVars) > 0 {
// Extract captures from the first implicit parameter.
arg0 := llvmFunction.Param(0)
for i, fv := range f.FreeVars {
addressPtr := fr.builder.CreateStructGEP(arg0, i, "")
address := fr.builder.CreateLoad(addressPtr, "")
fr.env[fv] = fr.NewValue(address, fv.Type())
}
paramOffset++
}
// Map parameter positions to indices. We use this
// when processing locals to map back to parameters
// when generating debug metadata.
paramPos := make(map[token.Pos]int)
for i, param := range f.Params {
paramPos[param.Pos()] = i + paramOffset
llparam := llvmFunction.Param(i + paramOffset)
fr.env[param] = fr.NewValue(llparam, param.Type())
}
// Allocate stack space for locals in the prologue block.
prologueBlock := llvm.InsertBasicBlock(fr.blocks[0], "prologue")
fr.builder.SetInsertPointAtEnd(prologueBlock)
for _, local := range f.Locals {
typ := fr.llvmtypes.ToLLVM(deref(local.Type()))
alloca := fr.builder.CreateAlloca(typ, local.Comment)
u.memsetZero(alloca, llvm.SizeOf(typ))
value := fr.NewValue(alloca, local.Type())
fr.env[local] = value
if fr.GenerateDebug {
paramIndex, ok := paramPos[local.Pos()]
if !ok {
paramIndex = -1
}
fr.debug.declare(fr.builder, local, alloca, paramIndex)
}
}
// Move any allocs relating to named results from the entry block
// to the prologue block, so they dominate the rundefers and recover
// blocks.
//
// TODO(axw) ask adonovan for a cleaner way of doing this, e.g.
// have ssa generate an entry block that defines Allocs and related
// stores, and then a separate block for function body instructions.
if f.Synthetic == "" {
if results := f.Signature.Results(); results != nil {
for i := 0; i < results.Len(); i++ {
result := results.At(i)
if result.Name() == "" {
break
}
for i, instr := range f.Blocks[0].Instrs {
if instr, ok := instr.(*ssa.Alloc); ok && instr.Heap && instr.Pos() == result.Pos() {
fr.instruction(instr)
instrs := f.Blocks[0].Instrs
instrs = append(instrs[:i], instrs[i+1:]...)
f.Blocks[0].Instrs = instrs
break
}
}
}
}
}
// If the function contains any defers, we must first call
// setjmp so we can call rundefers in response to a panic.
// We can short-circuit the check for defers with
// f.Recover != nil.
if f.Recover != nil || hasDefer(f) {
rdblock := llvm.AddBasicBlock(llvmFunction, "rundefers")
defers := fr.builder.CreateAlloca(fr.runtime.defers.llvm, "")
fr.builder.CreateCall(fr.runtime.initdefers.LLVMValue(), []llvm.Value{defers}, "")
jb := fr.builder.CreateStructGEP(defers, 0, "")
jb = fr.builder.CreateBitCast(jb, llvm.PointerType(llvm.Int8Type(), 0), "")
result := fr.builder.CreateCall(fr.runtime.setjmp.LLVMValue(), []llvm.Value{jb}, "")
result = fr.builder.CreateIsNotNull(result, "")
fr.builder.CreateCondBr(result, rdblock, fr.blocks[0])
// We'll only get here via a panic, which must either be
// recovered or continue panicking up the stack without
// returning from "rundefers". The recover block may be
// nil even if we can recover, in which case we just need
// to return the zero value for each result (if any).
var recoverBlock llvm.BasicBlock
if f.Recover != nil {
recoverBlock = fr.block(f.Recover)
} else {
recoverBlock = llvm.AddBasicBlock(llvmFunction, "recover")
fr.builder.SetInsertPointAtEnd(recoverBlock)
var nresults int
results := f.Signature.Results()
if results != nil {
nresults = results.Len()
}
switch nresults {
case 0:
fr.builder.CreateRetVoid()
case 1:
fr.builder.CreateRet(llvm.ConstNull(fr.llvmtypes.ToLLVM(results.At(0).Type())))
default:
values := make([]llvm.Value, nresults)
for i := range values {
values[i] = llvm.ConstNull(fr.llvmtypes.ToLLVM(results.At(i).Type()))
}
fr.builder.CreateAggregateRet(values)
}
}
fr.builder.SetInsertPointAtEnd(rdblock)
fr.builder.CreateCall(fr.runtime.rundefers.LLVMValue(), nil, "")
fr.builder.CreateBr(recoverBlock)
} else {
fr.builder.CreateBr(fr.blocks[0])
}
for i, block := range f.Blocks {
fr.translateBlock(block, fr.blocks[i])
}
}