forked from OSchip/llvm-project
197 lines
6.8 KiB
Go
197 lines
6.8 KiB
Go
//===- interfaces.go - IR generation for interfaces -----------------------===//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file is distributed under the University of Illinois Open Source
|
|
// License. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// This file implements IR generation for dealing with interface values.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
package irgen
|
|
|
|
import (
|
|
"llvm.org/llgo/third_party/go.tools/go/types"
|
|
"llvm.org/llvm/bindings/go/llvm"
|
|
)
|
|
|
|
// interfaceMethod returns a function and receiver pointer for the specified
|
|
// interface and method pair.
|
|
func (fr *frame) interfaceMethod(lliface llvm.Value, ifacety types.Type, method *types.Func) (fn, recv *govalue) {
|
|
llitab := fr.builder.CreateExtractValue(lliface, 0, "")
|
|
recv = newValue(fr.builder.CreateExtractValue(lliface, 1, ""), types.Typ[types.UnsafePointer])
|
|
methodset := fr.types.MethodSet(ifacety)
|
|
// TODO(axw) cache ordered method index
|
|
index := -1
|
|
for i, m := range orderedMethodSet(methodset) {
|
|
if m.Obj() == method {
|
|
index = i
|
|
break
|
|
}
|
|
}
|
|
if index == -1 {
|
|
panic("could not find method index")
|
|
}
|
|
llitab = fr.builder.CreateBitCast(llitab, llvm.PointerType(llvm.PointerType(llvm.Int8Type(), 0), 0), "")
|
|
// Skip runtime type pointer.
|
|
llifnptr := fr.builder.CreateGEP(llitab, []llvm.Value{
|
|
llvm.ConstInt(llvm.Int32Type(), uint64(index+1), false),
|
|
}, "")
|
|
|
|
llifn := fr.builder.CreateLoad(llifnptr, "")
|
|
// Replace receiver type with unsafe.Pointer.
|
|
recvparam := types.NewParam(0, nil, "", types.Typ[types.UnsafePointer])
|
|
sig := method.Type().(*types.Signature)
|
|
sig = types.NewSignature(nil, recvparam, sig.Params(), sig.Results(), sig.Variadic())
|
|
fn = newValue(llifn, sig)
|
|
return
|
|
}
|
|
|
|
// compareInterfaces emits code to compare two interfaces for
|
|
// equality.
|
|
func (fr *frame) compareInterfaces(a, b *govalue) *govalue {
|
|
aNull := a.value.IsNull()
|
|
bNull := b.value.IsNull()
|
|
if aNull && bNull {
|
|
return newValue(boolLLVMValue(true), types.Typ[types.Bool])
|
|
}
|
|
|
|
compare := fr.runtime.emptyInterfaceCompare
|
|
aI := a.Type().Underlying().(*types.Interface).NumMethods() > 0
|
|
bI := b.Type().Underlying().(*types.Interface).NumMethods() > 0
|
|
switch {
|
|
case aI && bI:
|
|
compare = fr.runtime.interfaceCompare
|
|
case aI:
|
|
a = fr.convertI2E(a)
|
|
case bI:
|
|
b = fr.convertI2E(b)
|
|
}
|
|
|
|
result := compare.call(fr, a.value, b.value)[0]
|
|
result = fr.builder.CreateIsNull(result, "")
|
|
result = fr.builder.CreateZExt(result, llvm.Int8Type(), "")
|
|
return newValue(result, types.Typ[types.Bool])
|
|
}
|
|
|
|
func (fr *frame) makeInterface(llv llvm.Value, vty types.Type, iface types.Type) *govalue {
|
|
if _, ok := vty.Underlying().(*types.Pointer); !ok {
|
|
ptr := fr.createTypeMalloc(vty)
|
|
fr.builder.CreateStore(llv, ptr)
|
|
llv = ptr
|
|
}
|
|
return fr.makeInterfaceFromPointer(llv, vty, iface)
|
|
}
|
|
|
|
func (fr *frame) makeInterfaceFromPointer(vptr llvm.Value, vty types.Type, iface types.Type) *govalue {
|
|
i8ptr := llvm.PointerType(llvm.Int8Type(), 0)
|
|
llv := fr.builder.CreateBitCast(vptr, i8ptr, "")
|
|
value := llvm.Undef(fr.types.ToLLVM(iface))
|
|
itab := fr.types.getItabPointer(vty, iface.Underlying().(*types.Interface))
|
|
value = fr.builder.CreateInsertValue(value, itab, 0, "")
|
|
value = fr.builder.CreateInsertValue(value, llv, 1, "")
|
|
return newValue(value, iface)
|
|
}
|
|
|
|
// Reads the type descriptor from the given interface type.
|
|
func (fr *frame) getInterfaceTypeDescriptor(v *govalue) llvm.Value {
|
|
isempty := v.Type().Underlying().(*types.Interface).NumMethods() == 0
|
|
itab := fr.builder.CreateExtractValue(v.value, 0, "")
|
|
if isempty {
|
|
return itab
|
|
} else {
|
|
itabnonnull := fr.builder.CreateIsNotNull(itab, "")
|
|
return fr.loadOrNull(itabnonnull, itab, types.Typ[types.UnsafePointer]).value
|
|
}
|
|
}
|
|
|
|
// Reads the value from the given interface type, assuming that the
|
|
// interface holds a value of the correct type.
|
|
func (fr *frame) getInterfaceValue(v *govalue, ty types.Type) *govalue {
|
|
val := fr.builder.CreateExtractValue(v.value, 1, "")
|
|
if _, ok := ty.Underlying().(*types.Pointer); !ok {
|
|
typedval := fr.builder.CreateBitCast(val, llvm.PointerType(fr.types.ToLLVM(ty), 0), "")
|
|
val = fr.builder.CreateLoad(typedval, "")
|
|
}
|
|
return newValue(val, ty)
|
|
}
|
|
|
|
// If cond is true, reads the value from the given interface type, otherwise
|
|
// returns a nil value.
|
|
func (fr *frame) getInterfaceValueOrNull(cond llvm.Value, v *govalue, ty types.Type) *govalue {
|
|
val := fr.builder.CreateExtractValue(v.value, 1, "")
|
|
if _, ok := ty.Underlying().(*types.Pointer); ok {
|
|
val = fr.builder.CreateSelect(cond, val, llvm.ConstNull(val.Type()), "")
|
|
} else {
|
|
val = fr.loadOrNull(cond, val, ty).value
|
|
}
|
|
return newValue(val, ty)
|
|
}
|
|
|
|
func (fr *frame) interfaceTypeCheck(val *govalue, ty types.Type) (v *govalue, okval *govalue) {
|
|
tytd := fr.types.ToRuntime(ty)
|
|
if _, ok := ty.Underlying().(*types.Interface); ok {
|
|
var result []llvm.Value
|
|
if val.Type().Underlying().(*types.Interface).NumMethods() > 0 {
|
|
result = fr.runtime.ifaceI2I2.call(fr, tytd, val.value)
|
|
} else {
|
|
result = fr.runtime.ifaceE2I2.call(fr, tytd, val.value)
|
|
}
|
|
v = newValue(result[0], ty)
|
|
okval = newValue(result[1], types.Typ[types.Bool])
|
|
} else {
|
|
valtd := fr.getInterfaceTypeDescriptor(val)
|
|
tyequal := fr.runtime.typeDescriptorsEqual.call(fr, valtd, tytd)[0]
|
|
okval = newValue(tyequal, types.Typ[types.Bool])
|
|
tyequal = fr.builder.CreateTrunc(tyequal, llvm.Int1Type(), "")
|
|
|
|
v = fr.getInterfaceValueOrNull(tyequal, val, ty)
|
|
}
|
|
return
|
|
}
|
|
|
|
func (fr *frame) interfaceTypeAssert(val *govalue, ty types.Type) *govalue {
|
|
if _, ok := ty.Underlying().(*types.Interface); ok {
|
|
return fr.changeInterface(val, ty, true)
|
|
} else {
|
|
valtytd := fr.types.ToRuntime(val.Type())
|
|
valtd := fr.getInterfaceTypeDescriptor(val)
|
|
tytd := fr.types.ToRuntime(ty)
|
|
fr.runtime.checkInterfaceType.call(fr, valtd, tytd, valtytd)
|
|
|
|
return fr.getInterfaceValue(val, ty)
|
|
}
|
|
}
|
|
|
|
// convertI2E converts a non-empty interface value to an empty interface.
|
|
func (fr *frame) convertI2E(v *govalue) *govalue {
|
|
td := fr.getInterfaceTypeDescriptor(v)
|
|
val := fr.builder.CreateExtractValue(v.value, 1, "")
|
|
|
|
typ := types.NewInterface(nil, nil)
|
|
intf := llvm.Undef(fr.types.ToLLVM(typ))
|
|
intf = fr.builder.CreateInsertValue(intf, td, 0, "")
|
|
intf = fr.builder.CreateInsertValue(intf, val, 1, "")
|
|
return newValue(intf, typ)
|
|
}
|
|
|
|
func (fr *frame) changeInterface(v *govalue, ty types.Type, assert bool) *govalue {
|
|
td := fr.getInterfaceTypeDescriptor(v)
|
|
tytd := fr.types.ToRuntime(ty)
|
|
var itab llvm.Value
|
|
if assert {
|
|
itab = fr.runtime.assertInterface.call(fr, tytd, td)[0]
|
|
} else {
|
|
itab = fr.runtime.convertInterface.call(fr, tytd, td)[0]
|
|
}
|
|
val := fr.builder.CreateExtractValue(v.value, 1, "")
|
|
|
|
intf := llvm.Undef(fr.types.ToLLVM(ty))
|
|
intf = fr.builder.CreateInsertValue(intf, itab, 0, "")
|
|
intf = fr.builder.CreateInsertValue(intf, val, 1, "")
|
|
return newValue(intf, ty)
|
|
}
|