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package compiler
// This file lowers channel operations (make/send/recv/close) to runtime calls
// or pseudo-operations that are lowered during goroutine lowering.
import (
"go/types"
"golang.org/x/tools/go/ssa"
"tinygo.org/x/go-llvm"
)
// emitMakeChan returns a new channel value for the given channel type.
func (c *Compiler) emitMakeChan(expr *ssa.MakeChan) (llvm.Value, error) {
chanType := c.getLLVMType(c.getRuntimeType("channel"))
size := c.targetData.TypeAllocSize(chanType)
sizeValue := llvm.ConstInt(c.uintptrType, size, false)
ptr := c.createRuntimeCall("alloc", []llvm.Value{sizeValue}, "chan.alloc")
ptr = c.builder.CreateBitCast(ptr, llvm.PointerType(chanType, 0), "chan")
return ptr, nil
}
// emitChanSend emits a pseudo chan send operation. It is lowered to the actual
// channel send operation during goroutine lowering.
func (c *Compiler) emitChanSend(frame *Frame, instr *ssa.Send) {
ch := c.getValue(frame, instr.Chan)
chanValue := c.getValue(frame, instr.X)
// store value-to-send
valueType := c.getLLVMType(instr.X.Type())
valueAlloca, valueAllocaCast, valueAllocaSize := c.createTemporaryAlloca(valueType, "chan.value")
c.builder.CreateStore(chanValue, valueAlloca)
// Do the send.
coroutine := c.createRuntimeCall("getCoroutine", nil, "")
valueSize := llvm.ConstInt(c.uintptrType, c.targetData.TypeAllocSize(chanValue.Type()), false)
c.createRuntimeCall("chanSend", []llvm.Value{coroutine, ch, valueAllocaCast, valueSize}, "")
// End the lifetime of the alloca.
// This also works around a bug in CoroSplit, at least in LLVM 8:
// https://bugs.llvm.org/show_bug.cgi?id=41742
c.emitLifetimeEnd(valueAllocaCast, valueAllocaSize)
}
// emitChanRecv emits a pseudo chan receive operation. It is lowered to the
// actual channel receive operation during goroutine lowering.
func (c *Compiler) emitChanRecv(frame *Frame, unop *ssa.UnOp) llvm.Value {
valueType := c.getLLVMType(unop.X.Type().(*types.Chan).Elem())
ch := c.getValue(frame, unop.X)
// Allocate memory to receive into.
valueAlloca, valueAllocaCast, valueAllocaSize := c.createTemporaryAlloca(valueType, "chan.value")
// Do the receive.
coroutine := c.createRuntimeCall("getCoroutine", nil, "")
valueSize := llvm.ConstInt(c.uintptrType, c.targetData.TypeAllocSize(valueType), false)
c.createRuntimeCall("chanRecv", []llvm.Value{coroutine, ch, valueAllocaCast, valueSize}, "")
received := c.builder.CreateLoad(valueAlloca, "chan.received")
c.emitLifetimeEnd(valueAllocaCast, valueAllocaSize)
if unop.CommaOk {
commaOk := c.createRuntimeCall("getTaskPromiseData", []llvm.Value{coroutine}, "chan.commaOk.wide")
commaOk = c.builder.CreateTrunc(commaOk, c.ctx.Int1Type(), "chan.commaOk")
tuple := llvm.Undef(c.ctx.StructType([]llvm.Type{valueType, c.ctx.Int1Type()}, false))
tuple = c.builder.CreateInsertValue(tuple, received, 0, "")
tuple = c.builder.CreateInsertValue(tuple, commaOk, 1, "")
return tuple
} else {
return received
}
}
// emitChanClose closes the given channel.
func (c *Compiler) emitChanClose(frame *Frame, param ssa.Value) {
valueType := c.getLLVMType(param.Type().(*types.Chan).Elem())
valueSize := llvm.ConstInt(c.uintptrType, c.targetData.TypeAllocSize(valueType), false)
ch := c.getValue(frame, param)
c.createRuntimeCall("chanClose", []llvm.Value{ch, valueSize}, "")
}
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