Method createGoroutineStartWrapper

compiler/goroutine.go:289–534

createGoroutineStartWrapper creates a wrapper for the task-based implementation of goroutines. For example, to call a function like this: func add(x, y int) int { ... } It creates a wrapper like this: func add$gowrapper(ptr *unsafe.Pointer) { args := (*struct{ x, y int })(ptr

(fnType llvm.Type, fn llvm.Value, prefix string, hasContext, isWasmExport bool, pos token.Pos)

// false, the parameter bundle is assumed to have no context parameter and undef
// is passed instead.
func (c *compilerContext) createGoroutineStartWrapper(fnType llvm.Type, fn llvm.Value, prefix string, hasContext, isWasmExport bool, pos token.Pos) llvm.Value {
	var wrapper llvm.Value

	b := &builder{
		compilerContext: c,
		Builder:         c.ctx.NewBuilder(),
	}
	defer b.Dispose()

	var deadlock llvm.Value
	var deadlockType llvm.Type
	if c.Scheduler == "asyncify" {
		deadlockType, deadlock = c.getFunction(c.program.ImportedPackage("runtime").Members["deadlock"].(*ssa.Function))
	}

	if !fn.IsAFunction().IsNil() {
		// See whether this wrapper has already been created. If so, return it.
		name := fn.Name()
		wrapperName := name + "$gowrapper"
		if isWasmExport {
			wrapperName += "-wasmexport"
		}
		wrapper = c.mod.NamedFunction(wrapperName)
		if !wrapper.IsNil() {
			return llvm.ConstPtrToInt(wrapper, c.uintptrType)
		}

		// Create the wrapper.
		wrapperType := llvm.FunctionType(c.ctx.VoidType(), []llvm.Type{c.dataPtrType}, false)
		wrapper = llvm.AddFunction(c.mod, wrapperName, wrapperType)
		c.addStandardAttributes(wrapper)
		wrapper.SetLinkage(llvm.LinkOnceODRLinkage)
		wrapper.SetUnnamedAddr(true)
		wrapper.AddAttributeAtIndex(-1, c.ctx.CreateStringAttribute("tinygo-gowrapper", name))
		entry := c.ctx.AddBasicBlock(wrapper, "entry")
		b.SetInsertPointAtEnd(entry)

		if c.Debug {
			pos := c.program.Fset.Position(pos)
			diFuncType := c.dibuilder.CreateSubroutineType(llvm.DISubroutineType{
				File:       c.getDIFile(pos.Filename),
				Parameters: nil, // do not show parameters in debugger
				Flags:      0,   // ?
			})
			difunc := c.dibuilder.CreateFunction(c.getDIFile(pos.Filename), llvm.DIFunction{
				Name:         "<goroutine wrapper>",
				File:         c.getDIFile(pos.Filename),
				Line:         pos.Line,
				Type:         diFuncType,
				LocalToUnit:  true,
				IsDefinition: true,
				ScopeLine:    0,
				Flags:        llvm.FlagPrototyped,
				Optimized:    true,
			})
			wrapper.SetSubprogram(difunc)
			b.SetCurrentDebugLocation(uint(pos.Line), uint(pos.Column), difunc, llvm.Metadata{})
		}