Golang Value.Type方法代碼示例

func (tm *TypeMap) makeRuntimeTypeGlobal(v llvm.Value, name string) (global, ptr llvm.Value) {
	global = llvm.AddGlobal(tm.module, v.Type(), typeSymbol(name))
	global.SetInitializer(v)
	global.SetLinkage(llvm.LinkOnceAnyLinkage)
	ptr = llvm.ConstBitCast(global, llvm.PointerType(tm.runtime.rtype.llvm, 0))
	return global, ptr
}

func (c *compiler) createMalloc(size llvm.Value) llvm.Value {
	malloc := c.NamedFunction("runtime.malloc", "func f(uintptr) unsafe.Pointer")
	if size.Type().IntTypeWidth() > c.target.IntPtrType().IntTypeWidth() {
		size = c.builder.CreateTrunc(size, c.target.IntPtrType(), "")
	}
	return c.builder.CreateCall(malloc, []llvm.Value{size}, "")
}

func (c *compiler) defineMallocFunction(fn llvm.Value) {
	entry := llvm.AddBasicBlock(fn, "entry")
	c.builder.SetInsertPointAtEnd(entry)
	size := fn.FirstParam()
	ptr := c.builder.CreateArrayMalloc(llvm.Int8Type(), size, "")
	// XXX memset to zero, or leave that to Go runtime code?
	fn_type := fn.Type().ElementType()
	result := c.builder.CreatePtrToInt(ptr, fn_type.ReturnType(), "")
	c.builder.CreateRet(result)
}

func (c *compiler) createMalloc(size llvm.Value) llvm.Value {
	malloc := c.runtime.malloc.LLVMValue()
	switch n := size.Type().IntTypeWidth() - c.target.IntPtrType().IntTypeWidth(); {
	case n < 0:
		size = c.builder.CreateZExt(size, c.target.IntPtrType(), "")
	case n > 0:
		size = c.builder.CreateTrunc(size, c.target.IntPtrType(), "")
	}
	return c.builder.CreateCall(malloc, []llvm.Value{size}, "")
}

func (c *compiler) createMalloc(size llvm.Value) llvm.Value {
	malloc := c.NamedFunction("runtime.malloc", "func(uintptr) unsafe.Pointer")
	switch n := size.Type().IntTypeWidth() - c.target.IntPtrType().IntTypeWidth(); {
	case n < 0:
		size = c.builder.CreateZExt(size, c.target.IntPtrType(), "")
	case n > 0:
		size = c.builder.CreateTrunc(size, c.target.IntPtrType(), "")
	}
	return c.builder.CreateCall(malloc, []llvm.Value{size}, "")
}

func (b *Builder) CreateLoad(v llvm.Value, name string) llvm.Value {
	if v.Type().ElementType() == b.types.ptrstandin {
		// We represent recursive pointer types (T = *T)
		// in LLVM as a pointer to "ptrstdin", where
		// ptrstandin is a unique named struct.
		//
		// Cast the the pointer to a pointer to its own type first.
		v = b.CreateBitCast(v, llvm.PointerType(v.Type(), 0), "")
	}
	return b.Builder.CreateLoad(v, name)
}

func (c *compiler) memsetZero(ptr llvm.Value, size llvm.Value) {
	memset := c.runtime.memset.LLVMValue()
	switch n := size.Type().IntTypeWidth() - c.target.IntPtrType().IntTypeWidth(); {
	case n < 0:
		size = c.builder.CreateZExt(size, c.target.IntPtrType(), "")
	case n > 0:
		size = c.builder.CreateTrunc(size, c.target.IntPtrType(), "")
	}
	ptr = c.builder.CreatePtrToInt(ptr, c.target.IntPtrType(), "")
	fill := llvm.ConstNull(llvm.Int8Type())
	c.builder.CreateCall(memset, []llvm.Value{ptr, fill, size}, "")
}

func (b *Builder) CreateStore(v, ptr llvm.Value) {
	if !b.types.ptrstandin.IsNil() {
		vtyp, ptrtyp := v.Type(), ptr.Type()
		if vtyp == ptrtyp {
			// We must be dealing with a pointer to a recursive pointer
			// type, so bitcast the pointer to a pointer to its own
			// type first.
			ptr = b.CreateBitCast(ptr, llvm.PointerType(ptrtyp, 0), "")
		}
	}
	b.Builder.CreateStore(v, ptr)
}

func (c *compiler) memsetZero(ptr llvm.Value, size llvm.Value) {
	memset := c.NamedFunction("runtime.memset", "func f(dst unsafe.Pointer, fill byte, size uintptr)")
	switch n := size.Type().IntTypeWidth() - c.target.IntPtrType().IntTypeWidth(); {
	case n < 0:
		size = c.builder.CreateZExt(size, c.target.IntPtrType(), "")
	case n > 0:
		size = c.builder.CreateTrunc(size, c.target.IntPtrType(), "")
	}
	ptr = c.builder.CreatePtrToInt(ptr, c.target.IntPtrType(), "")
	fill := llvm.ConstNull(llvm.Int8Type())
	c.builder.CreateCall(memset, []llvm.Value{ptr, fill, size}, "")
}

func (b *Builder) CreateStore(v, ptr llvm.Value) {
	if !b.types.ptrstandin.IsNil() {
		vtyp, ptrtyp := v.Type(), ptr.Type()
		if vtyp == ptrtyp || ptrtyp.ElementType() == b.types.ptrstandin {
			// We must be dealing with a pointer to a recursive pointer
			// type, so bitcast the value to the pointer's base, opaque
			// pointer type.
			v = b.CreateBitCast(v, ptrtyp.ElementType(), "")
		}
	}
	b.Builder.CreateStore(v, ptr)
}

// coerce yields a value of the the type specified, initialised
// to the exact bit pattern as in the specified value.
//
// Note: the specified value must be a non-aggregate, and its type
// and the specified type must have the same size.
func (c *compiler) coerce(v llvm.Value, t llvm.Type) llvm.Value {
	switch t.TypeKind() {
	case llvm.ArrayTypeKind, llvm.StructTypeKind:
		ptr := c.builder.CreateAlloca(t, "")
		ptrv := c.builder.CreateBitCast(ptr, llvm.PointerType(v.Type(), 0), "")
		c.builder.CreateStore(v, ptrv)
		return c.builder.CreateLoad(ptr, "")
	default:
		return c.builder.CreateBitCast(v, t, "")
	}
	panic("unreachable")
}

func (b *Builder) CreateLoad(v llvm.Value, name string) llvm.Value {
	result := b.Builder.CreateLoad(v, name)
	if !b.types.ptrstandin.IsNil() && result.Type() == b.types.ptrstandin {
		// We represent recursive pointer types (T = *T)
		// in LLVM as a pointer to "ptrstdin", where
		// ptrstandin is a pointer to a unique named struct.
		//
		// Cast the result of loading the pointer back to
		// the same type as the pointer loaded from.
		result = b.CreateBitCast(result, v.Type(), "")
	}
	return result
}

func (c *compiler) buildPtrRecvFunction(fn llvm.Value) llvm.Value {
	defer c.builder.SetInsertPointAtEnd(c.builder.GetInsertBlock())
	ifname := "*" + fn.Name()
	ifn := c.module.Module.NamedFunction(ifname)
	fntyp := fn.Type().ElementType()
	entry := llvm.AddBasicBlock(ifn, "entry")
	c.builder.SetInsertPointAtEnd(entry)
	args := ifn.Params()
	args[0] = c.builder.CreateLoad(args[0], "recv")
	result := c.builder.CreateCall(fn, args, "")
	if fntyp.ReturnType().TypeKind() == llvm.VoidTypeKind {
		c.builder.CreateRetVoid()
	} else {
		c.builder.CreateRet(result)
	}
	return ifn
}

func (tm *TypeMap) makeRuntimeTypeGlobal(v llvm.Value) (global, ptr llvm.Value) {
	// Each runtime type is preceded by an interface{}.
	initType := llvm.StructType([]llvm.Type{tm.runtimeType, v.Type()}, false)
	global = llvm.AddGlobal(tm.module, initType, "")
	ptr = llvm.ConstBitCast(global, llvm.PointerType(tm.runtimeType, 0))

	// interface{} containing v's *commonType representation.
	runtimeTypeValue := llvm.Undef(tm.runtimeType)
	zero := llvm.ConstNull(llvm.Int32Type())
	one := llvm.ConstInt(llvm.Int32Type(), 1, false)
	i8ptr := llvm.PointerType(llvm.Int8Type(), 0)
	if tm.commonTypePtrRuntimeType.IsNil() {
		// Create a dummy pointer value, which we'll update straight after
		// defining the runtime type info for commonType.
		tm.commonTypePtrRuntimeType = llvm.Undef(i8ptr)
		commonTypePtr := &types.Pointer{Base: tm.commonType}
		commonTypeGlobal, commonTypeRuntimeType := tm.makeRuntimeType(tm.commonType)
		tm.types[tm.commonType.String()] = runtimeTypeInfo{commonTypeGlobal, commonTypeRuntimeType}
		commonTypePtrGlobal, commonTypePtrRuntimeType := tm.makeRuntimeType(commonTypePtr)
		tm.types[commonTypePtr.String()] = runtimeTypeInfo{commonTypePtrGlobal, commonTypePtrRuntimeType}
		tm.commonTypePtrRuntimeType = llvm.ConstBitCast(commonTypePtrRuntimeType, i8ptr)
		if tm.pkgpath == tm.commonType.Package {
			// Update the interace{} header of the commonType/*commonType
			// runtime types we just created.
			for _, g := range [...]llvm.Value{commonTypeGlobal, commonTypePtrGlobal} {
				init := g.Initializer()
				typptr := tm.commonTypePtrRuntimeType
				runtimeTypeValue := llvm.ConstExtractValue(init, []uint32{0})
				runtimeTypeValue = llvm.ConstInsertValue(runtimeTypeValue, typptr, []uint32{0})
				init = llvm.ConstInsertValue(init, runtimeTypeValue, []uint32{0})
				g.SetInitializer(init)
			}
		}
	}
	commonTypePtr := llvm.ConstGEP(global, []llvm.Value{zero, one})
	commonTypePtr = llvm.ConstBitCast(commonTypePtr, i8ptr)
	runtimeTypeValue = llvm.ConstInsertValue(runtimeTypeValue, tm.commonTypePtrRuntimeType, []uint32{0})
	runtimeTypeValue = llvm.ConstInsertValue(runtimeTypeValue, commonTypePtr, []uint32{1})

	init := llvm.Undef(initType)
	init = llvm.ConstInsertValue(init, runtimeTypeValue, []uint32{0})
	init = llvm.ConstInsertValue(init, v, []uint32{1})
	global.SetInitializer(init)

	return global, ptr
}

// coerce yields a value of the the type specified, initialised
// to the exact bit pattern as in the specified value.
//
// Note: the value's type and the specified target type must have
// the same size. If the source is an aggregate, then the target
// must also be an aggregate with the same number of fields, each
// of which must have the same size.
func coerce(b llvm.Builder, v llvm.Value, t llvm.Type) llvm.Value {
	// FIXME don't do this with alloca
	switch t.TypeKind() {
	case llvm.ArrayTypeKind, llvm.StructTypeKind:
		ptr := b.CreateAlloca(t, "")
		ptrv := b.CreateBitCast(ptr, llvm.PointerType(v.Type(), 0), "")
		b.CreateStore(v, ptrv)
		return b.CreateLoad(ptr, "")
	}
	vt := v.Type()
	switch vt.TypeKind() {
	case llvm.ArrayTypeKind, llvm.StructTypeKind:
		ptr := b.CreateAlloca(vt, "")
		b.CreateStore(v, ptr)
		ptrt := b.CreateBitCast(ptr, llvm.PointerType(t, 0), "")
		return b.CreateLoad(ptrt, "")
	}
	return b.CreateBitCast(v, t, "")
}