compiler: refactor starting new goroutines

Author: aykevl

compiler/compiler.go

@@ -1071,7 +1071,7 @@ func (c *Compiler) parseInstr(frame *Frame, instr ssa.Instruction) {
 				panic("StaticCallee returned an unexpected value")
 			}
 			params = append(params, context) // context parameter
-			c.emitStartGoroutine(calleeFn.LLVMFn, params)
+			frame.createGoInstruction(calleeFn.LLVMFn, params)
 		} else if !instr.Call.IsInvoke() {
 			// This is a function pointer.
 			// At the moment, two extra params are passed to the newly started
@@ -1089,7 +1089,7 @@ func (c *Compiler) parseInstr(frame *Frame, instr ssa.Instruction) {
 			default:
 				panic("unknown scheduler type")
 			}
-			c.emitStartGoroutine(funcPtr, params)
+			frame.createGoInstruction(funcPtr, params)
 		} else {
 			c.addError(instr.Pos(), "todo: go on interface call")
 		}

compiler/goroutine.go

@@ -3,27 +3,30 @@ package compiler
 // This file implements the 'go' keyword to start a new goroutine. See
 // goroutine-lowering.go for more details.
 
-import "tinygo.org/x/go-llvm"
+import (
+	"github.com/tinygo-org/tinygo/compiler/llvmutil"
+	"tinygo.org/x/go-llvm"
+)
 
-// emitStartGoroutine starts a new goroutine with the provided function pointer
+// createGoInstruction starts a new goroutine with the provided function pointer
 // and parameters.
 // In general, you should pass all regular parameters plus the context parameter.
 // There is one exception: the task-based scheduler needs to have the function
 // pointer passed in as a parameter too in addition to the context.
 //
 // Because a go statement doesn't return anything, return undef.
-func (c *Compiler) emitStartGoroutine(funcPtr llvm.Value, params []llvm.Value) llvm.Value {
-	paramBundle := c.emitPointerPack(params)
+func (b *builder) createGoInstruction(funcPtr llvm.Value, params []llvm.Value) llvm.Value {
+	paramBundle := b.emitPointerPack(params)
 	var callee llvm.Value
-	switch c.Scheduler() {
+	switch b.Scheduler() {
 	case "none", "tasks":
-		callee = c.createGoroutineStartWrapper(funcPtr)
+		callee = b.createGoroutineStartWrapper(funcPtr)
 	case "coroutines":
-		callee = c.builder.CreatePtrToInt(funcPtr, c.uintptrType, "")
+		callee = b.CreatePtrToInt(funcPtr, b.uintptrType, "")
 	default:
 		panic("unreachable")
 	}
-	c.createCall(c.mod.NamedFunction("internal/task.start"), []llvm.Value{callee, paramBundle, llvm.Undef(c.i8ptrType), llvm.ConstPointerNull(c.i8ptrType)}, "")
+	b.createCall(b.mod.NamedFunction("internal/task.start"), []llvm.Value{callee, paramBundle, llvm.Undef(b.i8ptrType), llvm.ConstPointerNull(b.i8ptrType)}, "")
 	return llvm.Undef(funcPtr.Type().ElementType().ReturnType())
 }
 
@@ -45,36 +48,34 @@ func (c *Compiler) emitStartGoroutine(funcPtr llvm.Value, params []llvm.Value) l
 // allows a single (pointer) argument to the newly started goroutine. Also, it
 // ignores the return value because newly started goroutines do not have a
 // return value.
-func (c *Compiler) createGoroutineStartWrapper(fn llvm.Value) llvm.Value {
+func (c *compilerContext) createGoroutineStartWrapper(fn llvm.Value) llvm.Value {
 	var wrapper llvm.Value
 
+	builder := c.ctx.NewBuilder()
+
 	if !fn.IsAFunction().IsNil() {
 		// See whether this wrapper has already been created. If so, return it.
 		name := fn.Name()
 		wrapper = c.mod.NamedFunction(name + "$gowrapper")
 		if !wrapper.IsNil() {
-			return c.builder.CreatePtrToInt(wrapper, c.uintptrType, "")
+			return llvm.ConstPtrToInt(wrapper, c.uintptrType)
 		}
 
-		// Save the current position in the IR builder.
-		currentBlock := c.builder.GetInsertBlock()
-		defer c.builder.SetInsertPointAtEnd(currentBlock)
-
 		// Create the wrapper.
 		wrapperType := llvm.FunctionType(c.ctx.VoidType(), []llvm.Type{c.i8ptrType}, false)
 		wrapper = llvm.AddFunction(c.mod, name+"$gowrapper", wrapperType)
 		wrapper.SetLinkage(llvm.PrivateLinkage)
 		wrapper.SetUnnamedAddr(true)
 		entry := c.ctx.AddBasicBlock(wrapper, "entry")
-		c.builder.SetInsertPointAtEnd(entry)
+		builder.SetInsertPointAtEnd(entry)
 
 		// Create the list of params for the call.
 		paramTypes := fn.Type().ElementType().ParamTypes()
-		params := c.emitPointerUnpack(wrapper.Param(0), paramTypes[:len(paramTypes)-1])
+		params := llvmutil.EmitPointerUnpack(builder, c.mod, wrapper.Param(0), paramTypes[:len(paramTypes)-1])
 		params = append(params, llvm.Undef(c.i8ptrType))
 
 		// Create the call.
-		c.builder.CreateCall(fn, params, "")
+		builder.CreateCall(fn, params, "")
 
 	} else {
 		// For a function pointer like this:
@@ -94,22 +95,18 @@ func (c *Compiler) createGoroutineStartWrapper(fn llvm.Value) llvm.Value {
 		// With a bit of luck, identical wrapper functions like these can be
 		// merged into one.
 
-		// Save the current position in the IR builder.
-		currentBlock := c.builder.GetInsertBlock()
-		defer c.builder.SetInsertPointAtEnd(currentBlock)
-
 		// Create the wrapper.
 		wrapperType := llvm.FunctionType(c.ctx.VoidType(), []llvm.Type{c.i8ptrType}, false)
 		wrapper = llvm.AddFunction(c.mod, ".gowrapper", wrapperType)
 		wrapper.SetLinkage(llvm.InternalLinkage)
 		wrapper.SetUnnamedAddr(true)
 		entry := c.ctx.AddBasicBlock(wrapper, "entry")
-		c.builder.SetInsertPointAtEnd(entry)
+		builder.SetInsertPointAtEnd(entry)
 
 		// Get the list of parameters, with the extra parameters at the end.
 		paramTypes := fn.Type().ElementType().ParamTypes()
 		paramTypes[len(paramTypes)-1] = fn.Type() // the last element is the function pointer
-		params := c.emitPointerUnpack(wrapper.Param(0), paramTypes)
+		params := llvmutil.EmitPointerUnpack(builder, c.mod, wrapper.Param(0), paramTypes)
 
 		// Get the function pointer.
 		fnPtr := params[len(params)-1]
@@ -119,13 +116,13 @@ func (c *Compiler) createGoroutineStartWrapper(fn llvm.Value) llvm.Value {
 		params[len(params)-1] = llvm.Undef(c.i8ptrType)
 
 		// Create the call.
-		c.builder.CreateCall(fnPtr, params, "")
+		builder.CreateCall(fnPtr, params, "")
 	}
 
 	// Finish the function. Every basic block must end in a terminator, and
 	// because goroutines never return a value we can simply return void.
-	c.builder.CreateRetVoid()
+	builder.CreateRetVoid()
 
 	// Return a ptrtoint of the wrapper, not the function itself.
-	return c.builder.CreatePtrToInt(wrapper, c.uintptrType, "")
+	return builder.CreatePtrToInt(wrapper, c.uintptrType, "")
 }