Exemple #1
0
// stringIterNext advances the iterator, and returns the tuple (ok, k, v).
func (c *compiler) stringIterNext(str *LLVMValue, preds []llvm.BasicBlock) *LLVMValue {
	// While Range/Next expresses a mutating operation, we represent them using
	// a Phi node where the first incoming branch (before the loop), and all
	// others take the previous value plus one.
	//
	// See ssa.go for comments on (and assertions of) our assumptions.
	index := c.builder.CreatePHI(c.types.inttype, "index")
	strnext := c.runtime.strnext.LLVMValue()
	args := []llvm.Value{
		c.coerceString(str.LLVMValue(), strnext.Type().ElementType().ParamTypes()[0]),
		index,
	}
	result := c.builder.CreateCall(strnext, args, "")
	nextindex := c.builder.CreateExtractValue(result, 0, "")
	runeval := c.builder.CreateExtractValue(result, 1, "")
	values := make([]llvm.Value, len(preds))
	values[0] = llvm.ConstNull(index.Type())
	for i, _ := range preds[1:] {
		values[i+1] = nextindex
	}
	index.AddIncoming(values, preds)

	// Create an (ok, index, rune) tuple.
	ok := c.builder.CreateIsNotNull(nextindex, "")
	typ := tupleType(types.Typ[types.Bool], types.Typ[types.Int], types.Typ[types.Rune])
	tuple := llvm.Undef(c.types.ToLLVM(typ))
	tuple = c.builder.CreateInsertValue(tuple, ok, 0, "")
	tuple = c.builder.CreateInsertValue(tuple, index, 1, "")
	tuple = c.builder.CreateInsertValue(tuple, runeval, 2, "")
	return c.NewValue(tuple, typ)
}
Exemple #2
0
func (c *compiler) makeInterface(v *LLVMValue, iface types.Type) *LLVMValue {
	llv := v.LLVMValue()
	lltyp := llv.Type()
	i8ptr := llvm.PointerType(llvm.Int8Type(), 0)
	if lltyp.TypeKind() == llvm.PointerTypeKind {
		llv = c.builder.CreateBitCast(llv, i8ptr, "")
	} else {
		// If the value fits exactly in a pointer, then we can just
		// bitcast it. Otherwise we need to malloc.
		if c.target.TypeStoreSize(lltyp) <= uint64(c.target.PointerSize()) {
			bits := c.target.TypeSizeInBits(lltyp)
			if bits > 0 {
				llv = coerce(c.builder, llv, llvm.IntType(int(bits)))
				llv = c.builder.CreateIntToPtr(llv, i8ptr, "")
			} else {
				llv = llvm.ConstNull(i8ptr)
			}
		} else {
			ptr := c.createTypeMalloc(lltyp)
			c.builder.CreateStore(llv, ptr)
			llv = c.builder.CreateBitCast(ptr, i8ptr, "")
		}
	}
	value := llvm.Undef(c.types.ToLLVM(iface))
	rtype := c.types.ToRuntime(v.Type())
	rtype = c.builder.CreateBitCast(rtype, llvm.PointerType(llvm.Int8Type(), 0), "")
	value = c.builder.CreateInsertValue(value, rtype, 0, "")
	value = c.builder.CreateInsertValue(value, llv, 1, "")
	if iface.Underlying().(*types.Interface).NumMethods() > 0 {
		result := c.NewValue(value, types.NewInterface(nil, nil))
		result, _ = result.convertE2I(iface)
		return result
	}
	return c.NewValue(value, iface)
}
Exemple #3
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// interfaceMethod returns a function pointer for the specified
// interface and method pair.
func (c *compiler) interfaceMethod(iface *LLVMValue, method *types.Func) *LLVMValue {
	lliface := iface.LLVMValue()
	llitab := c.builder.CreateExtractValue(lliface, 0, "")
	llvalue := c.builder.CreateExtractValue(lliface, 1, "")
	sig := method.Type().(*types.Signature)
	methodset := c.types.MethodSet(sig.Recv().Type())
	// TODO(axw) cache ordered method index
	var index int
	for i := 0; i < methodset.Len(); i++ {
		if methodset.At(i).Obj() == method {
			index = i
			break
		}
	}
	llitab = c.builder.CreateBitCast(llitab, llvm.PointerType(c.runtime.itab.llvm, 0), "")
	llifn := c.builder.CreateGEP(llitab, []llvm.Value{
		llvm.ConstInt(llvm.Int32Type(), 0, false),
		llvm.ConstInt(llvm.Int32Type(), 5, false), // index of itab.fun
	}, "")
	_ = index
	llifn = c.builder.CreateGEP(llifn, []llvm.Value{
		llvm.ConstInt(llvm.Int32Type(), uint64(index), false),
	}, "")
	llifn = c.builder.CreateLoad(llifn, "")
	// Strip receiver.
	sig = types.NewSignature(nil, nil, sig.Params(), sig.Results(), sig.Variadic())
	llfn := llvm.Undef(c.types.ToLLVM(sig))
	llifn = c.builder.CreateIntToPtr(llifn, llfn.Type().StructElementTypes()[0], "")
	llfn = c.builder.CreateInsertValue(llfn, llifn, 0, "")
	llfn = c.builder.CreateInsertValue(llfn, llvalue, 1, "")
	return c.NewValue(llfn, sig)
}
Exemple #4
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// mapLookup implements v[, ok] = m[k]
func (c *compiler) mapLookup(m, k *LLVMValue, commaOk bool) *LLVMValue {
	dyntyp := c.types.ToRuntime(m.Type())
	dyntyp = c.builder.CreatePtrToInt(dyntyp, c.target.IntPtrType(), "")

	stackptr := c.stacksave()
	llk := k.LLVMValue()
	pk := c.builder.CreateAlloca(llk.Type(), "")
	c.builder.CreateStore(llk, pk)
	elemtyp := m.Type().Underlying().(*types.Map).Elem()
	pv := c.builder.CreateAlloca(c.types.ToLLVM(elemtyp), "")
	ok := c.builder.CreateCall(
		c.runtime.mapaccess.LLVMValue(),
		[]llvm.Value{
			dyntyp,
			m.LLVMValue(),
			c.builder.CreatePtrToInt(pk, c.target.IntPtrType(), ""),
			c.builder.CreatePtrToInt(pv, c.target.IntPtrType(), ""),
		}, "",
	)
	v := c.builder.CreateLoad(pv, "")
	c.stackrestore(stackptr)
	if !commaOk {
		return c.NewValue(v, elemtyp)
	}

	typ := tupleType(elemtyp, types.Typ[types.Bool])
	tuple := llvm.Undef(c.types.ToLLVM(typ))
	tuple = c.builder.CreateInsertValue(tuple, v, 0, "")
	tuple = c.builder.CreateInsertValue(tuple, ok, 1, "")
	return c.NewValue(tuple, typ)
}
Exemple #5
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func (c *compiler) slice(x, low, high *LLVMValue) *LLVMValue {
	if low != nil {
		low = low.Convert(types.Typ[types.Int]).(*LLVMValue)
	} else {
		low = c.NewValue(llvm.ConstNull(c.types.inttype), types.Typ[types.Int])
	}

	if high != nil {
		high = high.Convert(types.Typ[types.Int]).(*LLVMValue)
	} else {
		// all bits set is -1
		high = c.NewValue(llvm.ConstAllOnes(c.types.inttype), types.Typ[types.Int])
	}

	switch typ := x.Type().Underlying().(type) {
	case *types.Pointer: // *array
		sliceslice := c.runtime.sliceslice.LLVMValue()
		i8slice := sliceslice.Type().ElementType().ReturnType()
		sliceValue := llvm.Undef(i8slice) // temporary slice
		arraytyp := typ.Elem().Underlying().(*types.Array)
		arrayptr := x.LLVMValue()
		arrayptr = c.builder.CreateBitCast(arrayptr, i8slice.StructElementTypes()[0], "")
		arraylen := llvm.ConstInt(c.llvmtypes.inttype, uint64(arraytyp.Len()), false)
		sliceValue = c.builder.CreateInsertValue(sliceValue, arrayptr, 0, "")
		sliceValue = c.builder.CreateInsertValue(sliceValue, arraylen, 1, "")
		sliceValue = c.builder.CreateInsertValue(sliceValue, arraylen, 2, "")
		sliceTyp := types.NewSlice(arraytyp.Elem())
		runtimeTyp := c.types.ToRuntime(sliceTyp)
		runtimeTyp = c.builder.CreatePtrToInt(runtimeTyp, c.target.IntPtrType(), "")
		args := []llvm.Value{runtimeTyp, sliceValue, low.LLVMValue(), high.LLVMValue()}
		result := c.builder.CreateCall(sliceslice, args, "")
		llvmSliceTyp := c.types.ToLLVM(sliceTyp)
		return c.NewValue(c.coerceSlice(result, llvmSliceTyp), sliceTyp)
	case *types.Slice:
		sliceslice := c.runtime.sliceslice.LLVMValue()
		i8slice := sliceslice.Type().ElementType().ReturnType()
		sliceValue := x.LLVMValue()
		sliceTyp := sliceValue.Type()
		sliceValue = c.coerceSlice(sliceValue, i8slice)
		runtimeTyp := c.types.ToRuntime(x.Type())
		runtimeTyp = c.builder.CreatePtrToInt(runtimeTyp, c.target.IntPtrType(), "")
		args := []llvm.Value{runtimeTyp, sliceValue, low.LLVMValue(), high.LLVMValue()}
		result := c.builder.CreateCall(sliceslice, args, "")
		return c.NewValue(c.coerceSlice(result, sliceTyp), x.Type())
	case *types.Basic:
		stringslice := c.runtime.stringslice.LLVMValue()
		llv := x.LLVMValue()
		args := []llvm.Value{
			c.coerceString(llv, stringslice.Type().ElementType().ParamTypes()[0]),
			low.LLVMValue(),
			high.LLVMValue(),
		}
		result := c.builder.CreateCall(stringslice, args, "")
		return c.NewValue(c.coerceString(result, llv.Type()), x.Type())
	default:
		panic("unimplemented")
	}
	panic("unreachable")
}
Exemple #6
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func (c *compiler) coerceString(v llvm.Value, typ llvm.Type) llvm.Value {
	result := llvm.Undef(typ)
	ptr := c.builder.CreateExtractValue(v, 0, "")
	len := c.builder.CreateExtractValue(v, 1, "")
	result = c.builder.CreateInsertValue(result, ptr, 0, "")
	result = c.builder.CreateInsertValue(result, len, 1, "")
	return result
}
Exemple #7
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// coerceSlice takes a slice of one element type and coerces it to a
// slice of another.
func (c *compiler) coerceSlice(src llvm.Value, dsttyp llvm.Type) llvm.Value {
	dst := llvm.Undef(dsttyp)
	srcmem := c.builder.CreateExtractValue(src, 0, "")
	srclen := c.builder.CreateExtractValue(src, 1, "")
	srccap := c.builder.CreateExtractValue(src, 2, "")
	dstmemtyp := dsttyp.StructElementTypes()[0]
	dstmem := c.builder.CreateBitCast(srcmem, dstmemtyp, "")
	dst = c.builder.CreateInsertValue(dst, dstmem, 0, "")
	dst = c.builder.CreateInsertValue(dst, srclen, 1, "")
	dst = c.builder.CreateInsertValue(dst, srccap, 2, "")
	return dst
}
Exemple #8
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// makeClosure creates a closure from a function pointer and
// a set of bindings. The bindings are addresses of captured
// variables.
func (c *compiler) makeClosure(fn *LLVMValue, bindings []*LLVMValue) *LLVMValue {
	types := make([]llvm.Type, len(bindings))
	for i, binding := range bindings {
		types[i] = c.types.ToLLVM(binding.Type())
	}
	block := c.createTypeMalloc(llvm.StructType(types, false))
	for i, binding := range bindings {
		addressPtr := c.builder.CreateStructGEP(block, i, "")
		c.builder.CreateStore(binding.LLVMValue(), addressPtr)
	}
	block = c.builder.CreateBitCast(block, llvm.PointerType(llvm.Int8Type(), 0), "")
	// fn is a raw function pointer; ToLLVM yields {*fn, *uint8}.
	closure := llvm.Undef(c.types.ToLLVM(fn.Type()))
	fnptr := c.builder.CreateBitCast(fn.LLVMValue(), closure.Type().StructElementTypes()[0], "")
	closure = c.builder.CreateInsertValue(closure, fnptr, 0, "")
	closure = c.builder.CreateInsertValue(closure, block, 1, "")
	return c.NewValue(closure, fn.Type())
}
Exemple #9
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// makeLiteralSlice allocates a new slice, storing in it the provided elements.
func (c *compiler) makeLiteralSlice(v []llvm.Value, elttyp types.Type) llvm.Value {
	n := llvm.ConstInt(c.types.inttype, uint64(len(v)), false)
	eltType := c.types.ToLLVM(elttyp)
	arrayType := llvm.ArrayType(eltType, len(v))
	mem := c.createMalloc(llvm.SizeOf(arrayType))
	mem = c.builder.CreateIntToPtr(mem, llvm.PointerType(eltType, 0), "")
	for i, value := range v {
		indices := []llvm.Value{llvm.ConstInt(llvm.Int32Type(), uint64(i), false)}
		ep := c.builder.CreateGEP(mem, indices, "")
		c.builder.CreateStore(value, ep)
	}
	slicetyp := types.NewSlice(elttyp)
	struct_ := llvm.Undef(c.types.ToLLVM(slicetyp))
	struct_ = c.builder.CreateInsertValue(struct_, mem, 0, "")
	struct_ = c.builder.CreateInsertValue(struct_, n, 1, "")
	struct_ = c.builder.CreateInsertValue(struct_, n, 2, "")
	return struct_
}
Exemple #10
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// chanRecv implements x[, ok] = <-ch
func (c *compiler) chanRecv(ch *LLVMValue, commaOk bool) *LLVMValue {
	elemtyp := ch.Type().Underlying().(*types.Chan).Elem()
	stackptr := c.stacksave()
	ptr := c.builder.CreateAlloca(c.types.ToLLVM(elemtyp), "")
	chanrecv := c.runtime.chanrecv.LLVMValue()
	chantyp := c.types.ToRuntime(ch.Type().Underlying())
	chantyp = c.builder.CreateBitCast(chantyp, chanrecv.Type().ElementType().ParamTypes()[0], "")
	ok := c.builder.CreateCall(chanrecv, []llvm.Value{
		chantyp,
		ch.LLVMValue(),
		c.builder.CreatePtrToInt(ptr, c.target.IntPtrType(), ""),
		boolLLVMValue(false), // nb
	}, "")
	elem := c.builder.CreateLoad(ptr, "")
	c.stackrestore(stackptr)
	if !commaOk {
		return c.NewValue(elem, elemtyp)
	}
	typ := tupleType(elemtyp, types.Typ[types.Bool])
	tuple := llvm.Undef(c.types.ToLLVM(typ))
	tuple = c.builder.CreateInsertValue(tuple, elem, 0, "")
	tuple = c.builder.CreateInsertValue(tuple, ok, 1, "")
	return c.NewValue(tuple, typ)
}
Exemple #11
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// indirectFunction creates an indirect function from a
// given function and arguments, suitable for use with
// "defer" and "go".
func (c *compiler) indirectFunction(fn *LLVMValue, args []*LLVMValue) *LLVMValue {
	nilarytyp := types.NewSignature(nil, nil, nil, nil, false)
	if len(args) == 0 {
		val := fn.LLVMValue()
		ptr := c.builder.CreateExtractValue(val, 0, "")
		ctx := c.builder.CreateExtractValue(val, 1, "")
		fnval := llvm.Undef(c.types.ToLLVM(nilarytyp))
		ptr = c.builder.CreateBitCast(ptr, fnval.Type().StructElementTypes()[0], "")
		ctx = c.builder.CreateBitCast(ctx, fnval.Type().StructElementTypes()[1], "")
		fnval = c.builder.CreateInsertValue(fnval, ptr, 0, "")
		fnval = c.builder.CreateInsertValue(fnval, ctx, 1, "")
		return c.NewValue(fnval, nilarytyp)
	}

	// Check if function pointer or context pointer is global/null.
	fnval := fn.LLVMValue()
	fnptr := fnval
	var nctx int
	var fnctx llvm.Value
	var fnctxindex uint64
	var globalfn bool
	if fnptr.Type().TypeKind() == llvm.StructTypeKind {
		fnptr = c.builder.CreateExtractValue(fnval, 0, "")
		fnctx = c.builder.CreateExtractValue(fnval, 1, "")
		globalfn = !fnptr.IsAFunction().IsNil()
		if !globalfn {
			nctx++
		}
		if !fnctx.IsNull() {
			fnctxindex = uint64(nctx)
			nctx++
		}
	} else {
		// We've got a raw global function pointer. Convert to <ptr,ctx>.
		fnval = llvm.ConstNull(c.types.ToLLVM(fn.Type()))
		fnval = llvm.ConstInsertValue(fnval, fnptr, []uint32{0})
		fn = c.NewValue(fnval, fn.Type())
		fnctx = llvm.ConstExtractValue(fnval, []uint32{1})
		globalfn = true
	}

	i8ptr := llvm.PointerType(llvm.Int8Type(), 0)
	llvmargs := make([]llvm.Value, len(args)+nctx)
	llvmargtypes := make([]llvm.Type, len(args)+nctx)
	for i, arg := range args {
		llvmargs[i+nctx] = arg.LLVMValue()
		llvmargtypes[i+nctx] = llvmargs[i+nctx].Type()
	}
	if !globalfn {
		llvmargtypes[0] = fnptr.Type()
		llvmargs[0] = fnptr
	}
	if !fnctx.IsNull() {
		llvmargtypes[fnctxindex] = fnctx.Type()
		llvmargs[fnctxindex] = fnctx
	}

	// TODO(axw) investigate an option for go statements
	// to allocate argument structure on the stack in the
	// initiator, and block until the spawned goroutine
	// has loaded the arguments from it.
	structtyp := llvm.StructType(llvmargtypes, false)
	argstruct := c.createTypeMalloc(structtyp)
	for i, llvmarg := range llvmargs {
		argptr := c.builder.CreateGEP(argstruct, []llvm.Value{
			llvm.ConstInt(llvm.Int32Type(), 0, false),
			llvm.ConstInt(llvm.Int32Type(), uint64(i), false)}, "")
		c.builder.CreateStore(llvmarg, argptr)
	}

	// Create a function that will take a pointer to a structure of the type
	// defined above, or no parameters if there are none to pass.
	fntype := llvm.FunctionType(llvm.VoidType(), []llvm.Type{argstruct.Type()}, false)
	indirectfn := llvm.AddFunction(c.module.Module, "", fntype)
	i8argstruct := c.builder.CreateBitCast(argstruct, i8ptr, "")
	currblock := c.builder.GetInsertBlock()
	c.builder.SetInsertPointAtEnd(llvm.AddBasicBlock(indirectfn, "entry"))
	argstruct = indirectfn.Param(0)
	newargs := make([]*LLVMValue, len(args))
	for i := range llvmargs[nctx:] {
		argptr := c.builder.CreateGEP(argstruct, []llvm.Value{
			llvm.ConstInt(llvm.Int32Type(), 0, false),
			llvm.ConstInt(llvm.Int32Type(), uint64(i+nctx), false)}, "")
		newargs[i] = c.NewValue(c.builder.CreateLoad(argptr, ""), args[i].Type())
	}

	// Unless we've got a global function, extract the
	// function pointer from the context.
	if !globalfn {
		fnval = llvm.Undef(fnval.Type())
		fnptrptr := c.builder.CreateGEP(argstruct, []llvm.Value{
			llvm.ConstInt(llvm.Int32Type(), 0, false),
			llvm.ConstInt(llvm.Int32Type(), 0, false)}, "")
		fnptr = c.builder.CreateLoad(fnptrptr, "")
		fnval = c.builder.CreateInsertValue(fnval, fnptr, 0, "")
	}
	if !fnctx.IsNull() {
		fnctxptr := c.builder.CreateGEP(argstruct, []llvm.Value{
			llvm.ConstInt(llvm.Int32Type(), 0, false),
			llvm.ConstInt(llvm.Int32Type(), fnctxindex, false)}, "")
		fnctx = c.builder.CreateLoad(fnctxptr, "")
		fnval = c.builder.CreateInsertValue(fnval, fnctx, 1, "")
		fn = c.NewValue(fnval, fn.Type())
	}
	c.createCall(fn, newargs)

	// Indirect function calls' return values are always ignored.
	c.builder.CreateRetVoid()
	c.builder.SetInsertPointAtEnd(currblock)

	fnval = llvm.Undef(c.types.ToLLVM(nilarytyp))
	indirectfn = c.builder.CreateBitCast(indirectfn, fnval.Type().StructElementTypes()[0], "")
	fnval = c.builder.CreateInsertValue(fnval, indirectfn, 0, "")
	fnval = c.builder.CreateInsertValue(fnval, i8argstruct, 1, "")
	fn = c.NewValue(fnval, nilarytyp)
	return fn
}
Exemple #12
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func (c *compiler) NewConstValue(v exact.Value, typ types.Type) *LLVMValue {
	switch {
	case v == nil:
		llvmtyp := c.types.ToLLVM(typ)
		return c.NewValue(llvm.ConstNull(llvmtyp), typ)

	case isString(typ):
		if isUntyped(typ) {
			typ = types.Typ[types.String]
		}
		llvmtyp := c.types.ToLLVM(typ)
		strval := exact.StringVal(v)
		strlen := len(strval)
		i8ptr := llvm.PointerType(llvm.Int8Type(), 0)
		var ptr llvm.Value
		if strlen > 0 {
			init := llvm.ConstString(strval, false)
			ptr = llvm.AddGlobal(c.module.Module, init.Type(), "")
			ptr.SetInitializer(init)
			ptr = llvm.ConstBitCast(ptr, i8ptr)
		} else {
			ptr = llvm.ConstNull(i8ptr)
		}
		len_ := llvm.ConstInt(c.types.inttype, uint64(strlen), false)
		llvmvalue := llvm.Undef(llvmtyp)
		llvmvalue = llvm.ConstInsertValue(llvmvalue, ptr, []uint32{0})
		llvmvalue = llvm.ConstInsertValue(llvmvalue, len_, []uint32{1})
		return c.NewValue(llvmvalue, typ)

	case isInteger(typ):
		if isUntyped(typ) {
			typ = types.Typ[types.Int]
		}
		llvmtyp := c.types.ToLLVM(typ)
		var llvmvalue llvm.Value
		if isUnsigned(typ) {
			v, _ := exact.Uint64Val(v)
			llvmvalue = llvm.ConstInt(llvmtyp, v, false)
		} else {
			v, _ := exact.Int64Val(v)
			llvmvalue = llvm.ConstInt(llvmtyp, uint64(v), true)
		}
		return c.NewValue(llvmvalue, typ)

	case isBoolean(typ):
		if isUntyped(typ) {
			typ = types.Typ[types.Bool]
		}
		var llvmvalue llvm.Value
		if exact.BoolVal(v) {
			llvmvalue = llvm.ConstAllOnes(llvm.Int1Type())
		} else {
			llvmvalue = llvm.ConstNull(llvm.Int1Type())
		}
		return c.NewValue(llvmvalue, typ)

	case isFloat(typ):
		if isUntyped(typ) {
			typ = types.Typ[types.Float64]
		}
		llvmtyp := c.types.ToLLVM(typ)
		floatval, _ := exact.Float64Val(v)
		llvmvalue := llvm.ConstFloat(llvmtyp, floatval)
		return c.NewValue(llvmvalue, typ)

	case typ == types.Typ[types.UnsafePointer]:
		llvmtyp := c.types.ToLLVM(typ)
		v, _ := exact.Uint64Val(v)
		llvmvalue := llvm.ConstInt(llvmtyp, v, false)
		return c.NewValue(llvmvalue, typ)

	case isComplex(typ):
		if isUntyped(typ) {
			typ = types.Typ[types.Complex128]
		}
		llvmtyp := c.types.ToLLVM(typ)
		floattyp := llvmtyp.StructElementTypes()[0]
		llvmvalue := llvm.ConstNull(llvmtyp)
		realv := exact.Real(v)
		imagv := exact.Imag(v)
		realfloatval, _ := exact.Float64Val(realv)
		imagfloatval, _ := exact.Float64Val(imagv)
		llvmre := llvm.ConstFloat(floattyp, realfloatval)
		llvmim := llvm.ConstFloat(floattyp, imagfloatval)
		llvmvalue = llvm.ConstInsertValue(llvmvalue, llvmre, []uint32{0})
		llvmvalue = llvm.ConstInsertValue(llvmvalue, llvmim, []uint32{1})
		return c.NewValue(llvmvalue, typ)
	}

	// Special case for string -> [](byte|rune)
	if u, ok := typ.Underlying().(*types.Slice); ok && isInteger(u.Elem()) {
		if v.Kind() == exact.String {
			strval := c.NewConstValue(v, types.Typ[types.String])
			return strval.Convert(typ).(*LLVMValue)
		}
	}

	panic(fmt.Sprintf("unhandled: t=%s(%T), v=%v(%T)", typ, typ, v, v))
}
Exemple #13
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func (v *LLVMValue) Convert(dsttyp types.Type) Value {
	b := v.compiler.builder

	// If it's a stack allocated value, we'll want to compare the
	// value type, not the pointer type.
	srctyp := v.typ

	// Get the underlying type, if any.
	origdsttyp := dsttyp
	dsttyp = dsttyp.Underlying()
	srctyp = srctyp.Underlying()

	// Identical (underlying) types? Just swap in the destination type.
	if types.Identical(srctyp, dsttyp) {
		return v.compiler.NewValue(v.LLVMValue(), origdsttyp)
	}

	// Both pointer types with identical underlying types? Same as above.
	if srctyp, ok := srctyp.(*types.Pointer); ok {
		if dsttyp, ok := dsttyp.(*types.Pointer); ok {
			srctyp := srctyp.Elem().Underlying()
			dsttyp := dsttyp.Elem().Underlying()
			if types.Identical(srctyp, dsttyp) {
				return v.compiler.NewValue(v.LLVMValue(), origdsttyp)
			}
		}
	}

	byteslice := types.NewSlice(types.Typ[types.Byte])
	runeslice := types.NewSlice(types.Typ[types.Rune])

	// string ->
	if isString(srctyp) {
		// (untyped) string -> string
		// XXX should untyped strings be able to escape go/types?
		if isString(dsttyp) {
			return v.compiler.NewValue(v.LLVMValue(), origdsttyp)
		}

		// string -> []byte
		if types.Identical(dsttyp, byteslice) {
			c := v.compiler
			value := v.LLVMValue()
			strdata := c.builder.CreateExtractValue(value, 0, "")
			strlen := c.builder.CreateExtractValue(value, 1, "")

			// Data must be copied, to prevent changes in
			// the byte slice from mutating the string.
			newdata := c.createMalloc(strlen)
			memcpy := c.runtime.memcpy.LLVMValue()
			c.builder.CreateCall(memcpy, []llvm.Value{
				newdata,
				c.builder.CreatePtrToInt(strdata, c.target.IntPtrType(), ""),
				strlen,
			}, "")
			strdata = c.builder.CreateIntToPtr(newdata, strdata.Type(), "")

			struct_ := llvm.Undef(c.types.ToLLVM(byteslice))
			struct_ = c.builder.CreateInsertValue(struct_, strdata, 0, "")
			struct_ = c.builder.CreateInsertValue(struct_, strlen, 1, "")
			struct_ = c.builder.CreateInsertValue(struct_, strlen, 2, "")
			return c.NewValue(struct_, byteslice)
		}

		// string -> []rune
		if types.Identical(dsttyp, runeslice) {
			return v.stringToRuneSlice()
		}
	}

	// []byte -> string
	if types.Identical(srctyp, byteslice) && isString(dsttyp) {
		c := v.compiler
		value := v.LLVMValue()
		data := c.builder.CreateExtractValue(value, 0, "")
		len := c.builder.CreateExtractValue(value, 1, "")

		// Data must be copied, to prevent changes in
		// the byte slice from mutating the string.
		newdata := c.createMalloc(len)
		memcpy := c.runtime.memcpy.LLVMValue()
		c.builder.CreateCall(memcpy, []llvm.Value{
			newdata,
			c.builder.CreatePtrToInt(data, c.target.IntPtrType(), ""),
			len,
		}, "")
		data = c.builder.CreateIntToPtr(newdata, data.Type(), "")

		struct_ := llvm.Undef(c.types.ToLLVM(types.Typ[types.String]))
		struct_ = c.builder.CreateInsertValue(struct_, data, 0, "")
		struct_ = c.builder.CreateInsertValue(struct_, len, 1, "")
		return c.NewValue(struct_, types.Typ[types.String])
	}

	// []rune -> string
	if types.Identical(srctyp, runeslice) && isString(dsttyp) {
		return v.runeSliceToString()
	}

	// rune -> string
	if isString(dsttyp) && isInteger(srctyp) {
		return v.runeToString()
	}

	// TODO other special conversions?
	llvm_type := v.compiler.types.ToLLVM(dsttyp)

	// Unsafe pointer conversions.
	if dsttyp == types.Typ[types.UnsafePointer] { // X -> unsafe.Pointer
		if _, isptr := srctyp.(*types.Pointer); isptr {
			value := b.CreatePtrToInt(v.LLVMValue(), llvm_type, "")
			return v.compiler.NewValue(value, origdsttyp)
		} else if srctyp == types.Typ[types.Uintptr] {
			return v.compiler.NewValue(v.LLVMValue(), origdsttyp)
		}
	} else if srctyp == types.Typ[types.UnsafePointer] { // unsafe.Pointer -> X
		if _, isptr := dsttyp.(*types.Pointer); isptr {
			value := b.CreateIntToPtr(v.LLVMValue(), llvm_type, "")
			return v.compiler.NewValue(value, origdsttyp)
		} else if dsttyp == types.Typ[types.Uintptr] {
			return v.compiler.NewValue(v.LLVMValue(), origdsttyp)
		}
	}

	lv := v.LLVMValue()
	srcType := lv.Type()
	switch srcType.TypeKind() {
	case llvm.IntegerTypeKind:
		switch llvm_type.TypeKind() {
		case llvm.IntegerTypeKind:
			srcBits := srcType.IntTypeWidth()
			dstBits := llvm_type.IntTypeWidth()
			delta := srcBits - dstBits
			switch {
			case delta < 0:
				if !isUnsigned(srctyp) {
					lv = b.CreateSExt(lv, llvm_type, "")
				} else {
					lv = b.CreateZExt(lv, llvm_type, "")
				}
			case delta > 0:
				lv = b.CreateTrunc(lv, llvm_type, "")
			}
			return v.compiler.NewValue(lv, origdsttyp)
		case llvm.FloatTypeKind, llvm.DoubleTypeKind:
			if !isUnsigned(v.Type()) {
				lv = b.CreateSIToFP(lv, llvm_type, "")
			} else {
				lv = b.CreateUIToFP(lv, llvm_type, "")
			}
			return v.compiler.NewValue(lv, origdsttyp)
		}
	case llvm.DoubleTypeKind:
		switch llvm_type.TypeKind() {
		case llvm.FloatTypeKind:
			lv = b.CreateFPTrunc(lv, llvm_type, "")
			return v.compiler.NewValue(lv, origdsttyp)
		case llvm.IntegerTypeKind:
			if !isUnsigned(dsttyp) {
				lv = b.CreateFPToSI(lv, llvm_type, "")
			} else {
				lv = b.CreateFPToUI(lv, llvm_type, "")
			}
			return v.compiler.NewValue(lv, origdsttyp)
		}
	case llvm.FloatTypeKind:
		switch llvm_type.TypeKind() {
		case llvm.DoubleTypeKind:
			lv = b.CreateFPExt(lv, llvm_type, "")
			return v.compiler.NewValue(lv, origdsttyp)
		case llvm.IntegerTypeKind:
			if !isUnsigned(dsttyp) {
				lv = b.CreateFPToSI(lv, llvm_type, "")
			} else {
				lv = b.CreateFPToUI(lv, llvm_type, "")
			}
			return v.compiler.NewValue(lv, origdsttyp)
		}
	}

	// Complex -> complex. Complexes are only convertible to other
	// complexes, contant conversions aside. So we can just check the
	// source type here; given that the types are not identical
	// (checked above), we can assume the destination type is the alternate
	// complex type.
	if isComplex(srctyp) {
		var fpcast func(llvm.Builder, llvm.Value, llvm.Type, string) llvm.Value
		var fptype llvm.Type
		if srctyp == types.Typ[types.Complex64] {
			fpcast = (llvm.Builder).CreateFPExt
			fptype = llvm.DoubleType()
		} else {
			fpcast = (llvm.Builder).CreateFPTrunc
			fptype = llvm.FloatType()
		}
		if fpcast != nil {
			realv := b.CreateExtractValue(lv, 0, "")
			imagv := b.CreateExtractValue(lv, 1, "")
			realv = fpcast(b, realv, fptype, "")
			imagv = fpcast(b, imagv, fptype, "")
			lv = llvm.Undef(v.compiler.types.ToLLVM(dsttyp))
			lv = b.CreateInsertValue(lv, realv, 0, "")
			lv = b.CreateInsertValue(lv, imagv, 1, "")
			return v.compiler.NewValue(lv, origdsttyp)
		}
	}
	panic(fmt.Sprintf("unimplemented conversion: %s (%s) -> %s", v.typ, lv.Type(), origdsttyp))
}
Exemple #14
0
// prepareCall returns the evaluated function and arguments.
//
// For builtins that may not be used in go/defer, prepareCall
// will emits inline code. In this case, prepareCall returns
// nil for fn and args, and returns a non-nil value for result.
func (fr *frame) prepareCall(instr ssa.CallInstruction) (fn *LLVMValue, args []*LLVMValue, result *LLVMValue) {
	call := instr.Common()
	args = make([]*LLVMValue, len(call.Args))
	for i, arg := range call.Args {
		args[i] = fr.value(arg)
	}

	if call.IsInvoke() {
		fn := fr.interfaceMethod(fr.value(call.Value), call.Method)
		return fn, args, nil
	}

	switch v := call.Value.(type) {
	case *ssa.Builtin:
		// handled below
	case *ssa.Function:
		// Function handled specially; value() will convert
		// a function to one with a context argument.
		fn = fr.resolveFunction(v)
		pair := llvm.ConstNull(fr.llvmtypes.ToLLVM(fn.Type()))
		pair = llvm.ConstInsertValue(pair, fn.LLVMValue(), []uint32{0})
		fn = fr.NewValue(pair, fn.Type())
		return fn, args, nil
	default:
		fn = fr.value(call.Value)
		return fn, args, nil
	}

	// Builtins may only be used in calls (i.e. can't be assigned),
	// and only print[ln], panic and recover may be used in go/defer.
	builtin := call.Value.(*ssa.Builtin)
	switch builtin.Name() {
	case "print", "println":
		// print/println generates a call-site specific anonymous
		// function to print the values. It's not inline because
		// print/println may be deferred.
		params := make([]*types.Var, len(call.Args))
		for i, arg := range call.Args {
			// make sure to use args[i].Type(), not call.Args[i].Type(),
			// as the evaluated expression converts untyped.
			params[i] = types.NewParam(arg.Pos(), nil, arg.Name(), args[i].Type())
		}
		sig := types.NewSignature(nil, nil, types.NewTuple(params...), nil, false)
		llfntyp := fr.llvmtypes.ToLLVM(sig)
		llfnptr := llvm.AddFunction(fr.module.Module, "", llfntyp.StructElementTypes()[0].ElementType())
		currBlock := fr.builder.GetInsertBlock()
		entry := llvm.AddBasicBlock(llfnptr, "entry")
		fr.builder.SetInsertPointAtEnd(entry)
		internalArgs := make([]Value, len(args))
		for i, arg := range args {
			internalArgs[i] = fr.NewValue(llfnptr.Param(i), arg.Type())
		}
		fr.printValues(builtin.Name() == "println", internalArgs...)
		fr.builder.CreateRetVoid()
		fr.builder.SetInsertPointAtEnd(currBlock)
		return fr.NewValue(llfnptr, sig), args, nil

	case "panic":
		panic("TODO: panic")

	case "recover":
		// TODO(axw) determine number of frames to skip in pc check
		indirect := fr.NewValue(llvm.ConstNull(llvm.Int32Type()), types.Typ[types.Int32])
		return fr.runtime.recover_, []*LLVMValue{indirect}, nil

	case "append":
		return nil, nil, fr.callAppend(args[0], args[1])

	case "close":
		return fr.runtime.chanclose, args, nil

	case "cap":
		return nil, nil, fr.callCap(args[0])

	case "len":
		return nil, nil, fr.callLen(args[0])

	case "copy":
		return nil, nil, fr.callCopy(args[0], args[1])

	case "delete":
		fr.callDelete(args[0], args[1])
		return nil, nil, nil

	case "real":
		return nil, nil, args[0].extractComplexComponent(0)

	case "imag":
		return nil, nil, args[0].extractComplexComponent(1)

	case "complex":
		r := args[0].LLVMValue()
		i := args[1].LLVMValue()
		typ := instr.Value().Type()
		cmplx := llvm.Undef(fr.llvmtypes.ToLLVM(typ))
		cmplx = fr.builder.CreateInsertValue(cmplx, r, 0, "")
		cmplx = fr.builder.CreateInsertValue(cmplx, i, 1, "")
		return nil, nil, fr.NewValue(cmplx, typ)

	default:
		panic("unimplemented: " + builtin.Name())
	}
}
Exemple #15
0
func (fr *frame) instruction(instr ssa.Instruction) {
	fr.logf("[%T] %v @ %s\n", instr, instr, fr.pkg.Prog.Fset.Position(instr.Pos()))
	if fr.GenerateDebug {
		fr.debug.setLocation(fr.builder, instr.Pos())
	}

	// Check if we'll need to backpatch; see comment
	// in fr.value().
	if v, ok := instr.(ssa.Value); ok {
		if b := fr.backpatcher(v); b != nil {
			defer b()
		}
	}

	switch instr := instr.(type) {
	case *ssa.Alloc:
		typ := fr.llvmtypes.ToLLVM(deref(instr.Type()))
		var value llvm.Value
		if instr.Heap {
			value = fr.createTypeMalloc(typ)
			value.SetName(instr.Comment)
			fr.env[instr] = fr.NewValue(value, instr.Type())
		} else {
			value = fr.env[instr].LLVMValue()
		}
		fr.memsetZero(value, llvm.SizeOf(typ))

	case *ssa.BinOp:
		lhs, rhs := fr.value(instr.X), fr.value(instr.Y)
		fr.env[instr] = lhs.BinaryOp(instr.Op, rhs).(*LLVMValue)

	case *ssa.Call:
		fn, args, result := fr.prepareCall(instr)
		// Some builtins may only be used immediately, and not
		// deferred; in this case, "fn" will be nil, and result
		// may be non-nil (it will be nil for builtins without
		// results.)
		if fn == nil {
			if result != nil {
				fr.env[instr] = result
			}
		} else {
			result = fr.createCall(fn, args)
			fr.env[instr] = result
		}

	case *ssa.ChangeInterface:
		x := fr.value(instr.X)
		// The source type must be a non-empty interface,
		// as ChangeInterface cannot fail (E2I may fail).
		if instr.Type().Underlying().(*types.Interface).NumMethods() > 0 {
			// TODO(axw) optimisation for I2I case where we
			// know statically the methods to carry over.
			x = x.convertI2E()
			x, _ = x.convertE2I(instr.Type())
		} else {
			x = x.convertI2E()
			x = fr.NewValue(x.LLVMValue(), instr.Type())
		}
		fr.env[instr] = x

	case *ssa.ChangeType:
		value := fr.value(instr.X).LLVMValue()
		if _, ok := instr.Type().Underlying().(*types.Pointer); ok {
			value = fr.builder.CreateBitCast(value, fr.llvmtypes.ToLLVM(instr.Type()), "")
		}
		v := fr.NewValue(value, instr.Type())
		if _, ok := instr.X.(*ssa.Phi); ok {
			v = phiValue(fr.compiler, v)
		}
		fr.env[instr] = v

	case *ssa.Convert:
		v := fr.value(instr.X)
		if _, ok := instr.X.(*ssa.Phi); ok {
			v = phiValue(fr.compiler, v)
		}
		fr.env[instr] = v.Convert(instr.Type()).(*LLVMValue)

	//case *ssa.DebugRef:

	case *ssa.Defer:
		fn, args, result := fr.prepareCall(instr)
		if result != nil {
			panic("illegal use of builtin in defer statement")
		}
		fn = fr.indirectFunction(fn, args)
		fr.createCall(fr.runtime.pushdefer, []*LLVMValue{fn})

	case *ssa.Extract:
		tuple := fr.value(instr.Tuple).LLVMValue()
		elem := fr.builder.CreateExtractValue(tuple, instr.Index, instr.Name())
		elemtyp := instr.Type()
		fr.env[instr] = fr.NewValue(elem, elemtyp)

	case *ssa.Field:
		value := fr.value(instr.X).LLVMValue()
		field := fr.builder.CreateExtractValue(value, instr.Field, instr.Name())
		fieldtyp := instr.Type()
		fr.env[instr] = fr.NewValue(field, fieldtyp)

	case *ssa.FieldAddr:
		// TODO: implement nil check and panic.
		// TODO: combine a chain of {Field,Index}Addrs into a single GEP.
		ptr := fr.value(instr.X).LLVMValue()
		fieldptr := fr.builder.CreateStructGEP(ptr, instr.Field, instr.Name())
		fieldptrtyp := instr.Type()
		fr.env[instr] = fr.NewValue(fieldptr, fieldptrtyp)

	case *ssa.Go:
		fn, args, result := fr.prepareCall(instr)
		if result != nil {
			panic("illegal use of builtin in go statement")
		}
		fn = fr.indirectFunction(fn, args)
		fr.createCall(fr.runtime.Go, []*LLVMValue{fn})

	case *ssa.If:
		cond := fr.value(instr.Cond).LLVMValue()
		block := instr.Block()
		trueBlock := fr.block(block.Succs[0])
		falseBlock := fr.block(block.Succs[1])
		fr.builder.CreateCondBr(cond, trueBlock, falseBlock)

	case *ssa.Index:
		// FIXME Surely we should be dealing with an
		// *array, so we can do a GEP?
		array := fr.value(instr.X).LLVMValue()
		arrayptr := fr.builder.CreateAlloca(array.Type(), "")
		fr.builder.CreateStore(array, arrayptr)
		index := fr.value(instr.Index).LLVMValue()
		zero := llvm.ConstNull(index.Type())
		addr := fr.builder.CreateGEP(arrayptr, []llvm.Value{zero, index}, "")
		fr.env[instr] = fr.NewValue(fr.builder.CreateLoad(addr, ""), instr.Type())

	case *ssa.IndexAddr:
		// TODO: implement nil-check and panic.
		// TODO: combine a chain of {Field,Index}Addrs into a single GEP.
		x := fr.value(instr.X).LLVMValue()
		index := fr.value(instr.Index).LLVMValue()
		var addr llvm.Value
		var elemtyp types.Type
		zero := llvm.ConstNull(index.Type())
		switch typ := instr.X.Type().Underlying().(type) {
		case *types.Slice:
			elemtyp = typ.Elem()
			x = fr.builder.CreateExtractValue(x, 0, "")
			addr = fr.builder.CreateGEP(x, []llvm.Value{index}, "")
		case *types.Pointer: // *array
			elemtyp = typ.Elem().Underlying().(*types.Array).Elem()
			addr = fr.builder.CreateGEP(x, []llvm.Value{zero, index}, "")
		}
		fr.env[instr] = fr.NewValue(addr, types.NewPointer(elemtyp))

	case *ssa.Jump:
		succ := instr.Block().Succs[0]
		fr.builder.CreateBr(fr.block(succ))

	case *ssa.Lookup:
		x := fr.value(instr.X)
		index := fr.value(instr.Index)
		if isString(x.Type().Underlying()) {
			fr.env[instr] = fr.stringIndex(x, index)
		} else {
			fr.env[instr] = fr.mapLookup(x, index, instr.CommaOk)
		}

	case *ssa.MakeChan:
		fr.env[instr] = fr.makeChan(instr.Type(), fr.value(instr.Size))

	case *ssa.MakeClosure:
		fn := fr.resolveFunction(instr.Fn.(*ssa.Function))
		bindings := make([]*LLVMValue, len(instr.Bindings))
		for i, binding := range instr.Bindings {
			bindings[i] = fr.value(binding)
		}
		fr.env[instr] = fr.makeClosure(fn, bindings)

	case *ssa.MakeInterface:
		receiver := fr.value(instr.X)
		fr.env[instr] = fr.makeInterface(receiver, instr.Type())

	case *ssa.MakeMap:
		fr.env[instr] = fr.makeMap(instr.Type(), fr.value(instr.Reserve))

	case *ssa.MakeSlice:
		length := fr.value(instr.Len)
		capacity := fr.value(instr.Cap)
		fr.env[instr] = fr.makeSlice(instr.Type(), length, capacity)

	case *ssa.MapUpdate:
		m := fr.value(instr.Map)
		k := fr.value(instr.Key)
		v := fr.value(instr.Value)
		fr.mapUpdate(m, k, v)

	case *ssa.Next:
		iter := fr.value(instr.Iter)
		if !instr.IsString {
			fr.env[instr] = fr.mapIterNext(iter)
			return
		}

		// String range
		//
		// We make some assumptions for now around the
		// current state of affairs in go.tools/ssa.
		//
		//  - Range's block is a predecessor of Next's.
		//      (this is currently true, but may change in the future;
		//       adonovan says he will expose the dominator tree
		//       computation in the future, which we can use here).
		//  - Next is the first non-Phi instruction in its block.
		//      (this is not strictly necessary; we can move the Phi
		//       to the top of the block, and defer the tuple creation
		//       to Extract).
		assert(instr.Iter.(*ssa.Range).Block() == instr.Block().Preds[0])
		for _, blockInstr := range instr.Block().Instrs {
			if instr == blockInstr {
				break
			}
			_, isphi := blockInstr.(*ssa.Phi)
			assert(isphi)
		}
		preds := instr.Block().Preds
		llpreds := make([]llvm.BasicBlock, len(preds))
		for i, b := range preds {
			llpreds[i] = fr.block(b)
		}
		fr.env[instr] = fr.stringIterNext(iter, llpreds)

	case *ssa.Panic:
		arg := fr.value(instr.X).LLVMValue()
		fr.builder.CreateCall(fr.runtime.panic_.LLVMValue(), []llvm.Value{arg}, "")
		fr.builder.CreateUnreachable()

	case *ssa.Phi:
		typ := instr.Type()
		phi := fr.builder.CreatePHI(fr.llvmtypes.ToLLVM(typ), instr.Comment)
		fr.env[instr] = fr.NewValue(phi, typ)
		values := make([]llvm.Value, len(instr.Edges))
		blocks := make([]llvm.BasicBlock, len(instr.Edges))
		block := instr.Block()
		for i, edge := range instr.Edges {
			values[i] = fr.value(edge).LLVMValue()
			blocks[i] = fr.block(block.Preds[i])
		}
		phi.AddIncoming(values, blocks)

	case *ssa.Range:
		x := fr.value(instr.X)
		switch x.Type().Underlying().(type) {
		case *types.Map:
			fr.env[instr] = fr.mapIterInit(x)
		case *types.Basic: // string
			fr.env[instr] = x
		default:
			panic(fmt.Sprintf("unhandled range for type %T", x.Type()))
		}

	case *ssa.Return:
		switch n := len(instr.Results); n {
		case 0:
			// https://code.google.com/p/go/issues/detail?id=7022
			if r := instr.Parent().Signature.Results(); r != nil && r.Len() > 0 {
				fr.builder.CreateUnreachable()
			} else {
				fr.builder.CreateRetVoid()
			}
		case 1:
			fr.builder.CreateRet(fr.value(instr.Results[0]).LLVMValue())
		default:
			values := make([]llvm.Value, n)
			for i, result := range instr.Results {
				values[i] = fr.value(result).LLVMValue()
			}
			fr.builder.CreateAggregateRet(values)
		}

	case *ssa.RunDefers:
		fr.builder.CreateCall(fr.runtime.rundefers.LLVMValue(), nil, "")

	case *ssa.Select:
		states := make([]selectState, len(instr.States))
		for i, state := range instr.States {
			states[i] = selectState{
				Dir:  state.Dir,
				Chan: fr.value(state.Chan),
				Send: fr.value(state.Send),
			}
		}
		fr.env[instr] = fr.chanSelect(states, instr.Blocking)

	case *ssa.Send:
		fr.chanSend(fr.value(instr.Chan), fr.value(instr.X))

	case *ssa.Slice:
		x := fr.value(instr.X)
		low := fr.value(instr.Low)
		high := fr.value(instr.High)
		fr.env[instr] = fr.slice(x, low, high)

	case *ssa.Store:
		addr := fr.value(instr.Addr).LLVMValue()
		value := fr.value(instr.Val).LLVMValue()
		// The bitcast is necessary to handle recursive pointer stores.
		addr = fr.builder.CreateBitCast(addr, llvm.PointerType(value.Type(), 0), "")
		fr.builder.CreateStore(value, addr)

	case *ssa.TypeAssert:
		x := fr.value(instr.X)
		if iface, ok := x.Type().Underlying().(*types.Interface); ok && iface.NumMethods() > 0 {
			x = x.convertI2E()
		}
		if !instr.CommaOk {
			if _, ok := instr.AssertedType.Underlying().(*types.Interface); ok {
				fr.env[instr] = x.mustConvertE2I(instr.AssertedType)
			} else {
				fr.env[instr] = x.mustConvertE2V(instr.AssertedType)
			}
		} else {
			var result, success *LLVMValue
			if _, ok := instr.AssertedType.Underlying().(*types.Interface); ok {
				result, success = x.convertE2I(instr.AssertedType)
			} else {
				result, success = x.convertE2V(instr.AssertedType)
			}
			resultval := result.LLVMValue()
			okval := success.LLVMValue()
			pairtyp := llvm.StructType([]llvm.Type{resultval.Type(), okval.Type()}, false)
			pair := llvm.Undef(pairtyp)
			pair = fr.builder.CreateInsertValue(pair, resultval, 0, "")
			pair = fr.builder.CreateInsertValue(pair, okval, 1, "")
			fr.env[instr] = fr.NewValue(pair, instr.Type())
		}

	case *ssa.UnOp:
		operand := fr.value(instr.X)
		switch instr.Op {
		case token.ARROW:
			fr.env[instr] = fr.chanRecv(operand, instr.CommaOk)
		case token.MUL:
			// The bitcast is necessary to handle recursive pointer loads.
			llptr := fr.builder.CreateBitCast(operand.LLVMValue(), llvm.PointerType(fr.llvmtypes.ToLLVM(instr.Type()), 0), "")
			fr.env[instr] = fr.NewValue(fr.builder.CreateLoad(llptr, ""), instr.Type())
		default:
			fr.env[instr] = operand.UnaryOp(instr.Op).(*LLVMValue)
		}

	default:
		panic(fmt.Sprintf("unhandled: %v", instr))
	}
}