forked from go-llvm/llgo
/
slice.go
119 lines (111 loc) · 4.87 KB
/
slice.go
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// Copyright 2012 The llgo Authors.
// Use of this source code is governed by an MIT-style
// license that can be found in the LICENSE file.
package llgo
import (
"code.google.com/p/go.tools/go/types"
"github.com/go-llvm/llvm"
)
// 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_
}
// makeSlice allocates a new slice with the optional length and capacity,
// initialising its contents to their zero values.
func (c *compiler) makeSlice(sliceType types.Type, length, capacity *LLVMValue) *LLVMValue {
length = length.Convert(types.Typ[types.Int]).(*LLVMValue)
capacity = capacity.Convert(types.Typ[types.Int]).(*LLVMValue)
makeslice := c.runtime.makeslice.LLVMValue()
runtimeType := c.builder.CreatePtrToInt(c.types.ToRuntime(sliceType), c.target.IntPtrType(), "")
llslice := c.builder.CreateCall(makeslice, []llvm.Value{
runtimeType, length.LLVMValue(), capacity.LLVMValue(),
}, "")
llslice = c.coerceSlice(llslice, c.types.ToLLVM(sliceType))
return c.NewValue(llslice, sliceType)
}
// 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
}
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")
}