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implement comptime pointer cast

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closes #955
closes #1835
This commit is contained in:
Andrew Kelley 2018-12-16 12:03:37 -05:00
parent 7533d1b14c
commit 757d0665ae
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GPG key ID: 7C5F548F728501A9
2 changed files with 31 additions and 3 deletions
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23
src/ir.cpp
View file

@ -166,6 +166,7 @@ static Error ir_read_const_ptr(IrAnalyze *ira, AstNode *source_node,
static IrInstruction *ir_analyze_ptr_cast(IrAnalyze *ira, IrInstruction *source_instr, IrInstruction *ptr, static IrInstruction *ir_analyze_ptr_cast(IrAnalyze *ira, IrInstruction *source_instr, IrInstruction *ptr,
ZigType *dest_type, IrInstruction *dest_type_src); ZigType *dest_type, IrInstruction *dest_type_src);
static ConstExprValue *ir_resolve_const(IrAnalyze *ira, IrInstruction *value, UndefAllowed undef_allowed); static ConstExprValue *ir_resolve_const(IrAnalyze *ira, IrInstruction *value, UndefAllowed undef_allowed);
static void copy_const_val(ConstExprValue *dest, ConstExprValue *src, bool same_global_refs);
static ConstExprValue *const_ptr_pointee_unchecked(CodeGen *g, ConstExprValue *const_val) { static ConstExprValue *const_ptr_pointee_unchecked(CodeGen *g, ConstExprValue *const_val) {
assert(get_src_ptr_type(const_val->type) != nullptr); assert(get_src_ptr_type(const_val->type) != nullptr);
@ -7364,15 +7365,31 @@ static ErrorMsg *ir_add_error(IrAnalyze *ira, IrInstruction *source_instruction,
return ir_add_error_node(ira, source_instruction->source_node, msg); return ir_add_error_node(ira, source_instruction->source_node, msg);
} }
// This function takes a comptime ptr and makes the child const value conform to the type
// described by the pointer.
static Error eval_comptime_ptr_reinterpret(IrAnalyze *ira, AstNode *source_node, ConstExprValue *ptr_val) {
Error err;
assert(ptr_val->type->id == ZigTypeIdPointer);
ConstExprValue tmp = {};
tmp.special = ConstValSpecialStatic;
tmp.type = ptr_val->type->data.pointer.child_type;
if ((err = ir_read_const_ptr(ira, source_node, &tmp, ptr_val)))
return err;
ConstExprValue *child_val = const_ptr_pointee_unchecked(ira->codegen, ptr_val);
copy_const_val(child_val, &tmp, false);
return ErrorNone;
}
static ConstExprValue *ir_const_ptr_pointee(IrAnalyze *ira, ConstExprValue *const_val, AstNode *source_node) { static ConstExprValue *ir_const_ptr_pointee(IrAnalyze *ira, ConstExprValue *const_val, AstNode *source_node) {
Error err;
ConstExprValue *val = const_ptr_pointee_unchecked(ira->codegen, const_val); ConstExprValue *val = const_ptr_pointee_unchecked(ira->codegen, const_val);
assert(val != nullptr); assert(val != nullptr);
assert(const_val->type->id == ZigTypeIdPointer); assert(const_val->type->id == ZigTypeIdPointer);
ZigType *expected_type = const_val->type->data.pointer.child_type; ZigType *expected_type = const_val->type->data.pointer.child_type;
if (!types_have_same_zig_comptime_repr(val->type, expected_type)) { if (!types_have_same_zig_comptime_repr(val->type, expected_type)) {
ir_add_error_node(ira, source_node, if ((err = eval_comptime_ptr_reinterpret(ira, source_node, const_val)))
buf_sprintf("TODO handle comptime reinterpreted pointer. See https://github.com/ziglang/zig/issues/955"));
return nullptr; return nullptr;
return const_ptr_pointee_unchecked(ira->codegen, const_val);
} }
return val; return val;
} }
@ -19990,6 +20007,8 @@ static IrInstruction *ir_analyze_instruction_ptr_cast(IrAnalyze *ira, IrInstruct
} }
static void buf_write_value_bytes(CodeGen *codegen, uint8_t *buf, ConstExprValue *val) { static void buf_write_value_bytes(CodeGen *codegen, uint8_t *buf, ConstExprValue *val) {
if (val->special == ConstValSpecialUndef)
val->special = ConstValSpecialStatic;
assert(val->special == ConstValSpecialStatic); assert(val->special == ConstValSpecialStatic);
switch (val->type->id) { switch (val->type->id) {
case ZigTypeIdInvalid: case ZigTypeIdInvalid:

9
std/mem.zig
View file

@ -510,6 +510,15 @@ pub fn readIntSlice(comptime T: type, bytes: []const u8, endian: builtin.Endian)
return readInt(T, @ptrCast(*const [@sizeOf(T)]u8, bytes.ptr), endian); return readInt(T, @ptrCast(*const [@sizeOf(T)]u8, bytes.ptr), endian);
} }
test "comptime read/write int" {
comptime {
var bytes: [2]u8 = undefined;
std.mem.writeIntLittle(u16, &bytes, 0x1234);
const result = std.mem.readIntBig(u16, &bytes);
std.debug.assert(result == 0x3412);
}
}
test "readIntBig and readIntLittle" { test "readIntBig and readIntLittle" {
assert(readIntSliceBig(u0, []u8{}) == 0x0); assert(readIntSliceBig(u0, []u8{}) == 0x0);
assert(readIntSliceLittle(u0, []u8{}) == 0x0); assert(readIntSliceLittle(u0, []u8{}) == 0x0);