Commit 91989e70ba68e3543acffef079d97c9416b5259c | zig

author	Matthew McAllister <matthew.mcallister.0@gmail.com> 2019-02-12 21:22:16-08:00
committer	Matthew McAllister <matthew.mcallister.0@gmail.com> 2019-02-16 17:37:47-08:00
log	91989e70ba68e3543acffef079d97c9416b5259c
tree	71323c9859706b377290c5bbca22c661afaf60dc
parent	c3c92ca8b1ada4faed14a9770ab7ed6536edaa15

Fix lvalue dereference type checking

Previously, if a dereference instruction was an lvalue, it would fail to
typecheck that the value being dereferenced was indeed a pointer.
Although a little clunky, this change obviates the need for redundant
type checks scattered about the analysis.

3 files changed, 45 insertions(+), 29 deletions(-)

src
- all_types.hpp
- ir.cpp
test
- compile_errors.zig

src/all_types.hpp+6-5

 @@ -2091,6 +2091,11 @@ struct IrBasicBlock {
     IrInstruction *must_be_comptime_source_instr;
 };
+enum LVal {
+    LValNone,
+    LValPtr,
+};
 // These instructions are in transition to having "pass 1" instructions
 // and "pass 2" instructions. The pass 1 instructions are suffixed with Src
 // and pass 2 are suffixed with Gen.
 @@ -2354,6 +2359,7 @@ struct IrInstructionUnOp {
     IrUnOp op_id;
     IrInstruction *value;
+    LVal lval;
 };
 enum IrBinOp {
 @@ -3090,11 +3096,6 @@ struct IrInstructionTypeName {
     IrInstruction *type_value;
 };
-enum LVal {
-    LValNone,
-    LValPtr,
-};
 struct IrInstructionDeclRef {
     IrInstruction base;

src/ir.cpp+18-21

...	@@ -1307,6 +1307,7 @@ static IrInstruction ir_build_un_op(IrBuilder irb, Scope scope, AstNode sour	...	@@ -1307,6 +1307,7 @@ static IrInstruction ir_build_un_op(IrBuilder irb, Scope scope, AstNode sour
1307	IrInstructionUnOp *br_instruction = ir_build_instruction<IrInstructionUnOp>(irb, scope, source_node);	1307	IrInstructionUnOp *br_instruction = ir_build_instruction<IrInstructionUnOp>(irb, scope, source_node);
1308	br_instruction->op_id = op_id;	1308	br_instruction->op_id = op_id;
1309	br_instruction->value = value;	1309	br_instruction->value = value;
		1310	br_instruction->lval = LValNone;
1310		1311
1311	ir_ref_instruction(value, irb->current_basic_block);	1312	ir_ref_instruction(value, irb->current_basic_block);
1312		1313
...	@@ -7223,7 +7224,13 @@ static IrInstruction ir_gen_node_raw(IrBuilder irb, AstNode node, Scope scop	...	@@ -7223,7 +7224,13 @@ static IrInstruction ir_gen_node_raw(IrBuilder irb, AstNode node, Scope scop
7223	if (value == irb->codegen->invalid_instruction)	7224	if (value == irb->codegen->invalid_instruction)
7224	return value;	7225	return value;
7225		7226
7226	return ir_build_un_op(irb, scope, node, IrUnOpDereference, value);	7227	// We essentially just converted any lvalue from &(x.) to (&x).;
		7228	// this inhibits checking that x is a pointer later, so we directly
		7229	// record whether the pointer check is needed
		7230	IrInstructionUnOp result = (IrInstructionUnOp)ir_build_un_op(irb, scope, node, IrUnOpDereference, value);
		7231	result->lval = lval;
		7232
		7233	return &result->base;
7227	}	7234	}
7228	case NodeTypeUnwrapOptional: {	7235	case NodeTypeUnwrapOptional: {
7229	AstNode *expr_node = node->data.unwrap_optional.expr;	7236	AstNode *expr_node = node->data.unwrap_optional.expr;
...	@@ -11437,7 +11444,7 @@ static IrInstruction ir_get_deref(IrAnalyze ira, IrInstruction *source_instruc	...	@@ -11437,7 +11444,7 @@ static IrInstruction ir_get_deref(IrAnalyze ira, IrInstruction *source_instruc
11437	return load_ptr_instruction;	11444	return load_ptr_instruction;
11438	} else {	11445	} else {
11439	ir_add_error_node(ira, source_instruction->source_node,	11446	ir_add_error_node(ira, source_instruction->source_node,
11440	buf_sprintf("attempt to dereference non pointer type '%s'",	11447	buf_sprintf("attempt to dereference non-pointer type '%s'",
11441	buf_ptr(&type_entry->name)));	11448	buf_ptr(&type_entry->name)));
11442	return ira->codegen->invalid_instruction;	11449	return ira->codegen->invalid_instruction;
11443	}	11450	}
...	@@ -13616,12 +13623,6 @@ no_mem_slot:	...	@@ -13616,12 +13623,6 @@ no_mem_slot:
13616	static IrInstruction ir_analyze_store_ptr(IrAnalyze ira, IrInstruction *source_instr,	13623	static IrInstruction ir_analyze_store_ptr(IrAnalyze ira, IrInstruction *source_instr,
13617	IrInstruction ptr, IrInstruction uncasted_value)	13624	IrInstruction ptr, IrInstruction uncasted_value)
13618	{	13625	{
13619	if (ptr->value.type->id != ZigTypeIdPointer) {
13620	ir_add_error(ira, ptr,
13621	buf_sprintf("attempt to dereference non pointer type '%s'", buf_ptr(&ptr->value.type->name)));
13622	return ira->codegen->invalid_instruction;
13623	}
13624
13625	if (ptr->value.data.x_ptr.special == ConstPtrSpecialDiscard) {	13626	if (ptr->value.data.x_ptr.special == ConstPtrSpecialDiscard) {
13626	return ir_const_void(ira, source_instr);	13627	return ir_const_void(ira, source_instr);
13627	}	13628	}
...	@@ -14550,11 +14551,18 @@ static IrInstruction ir_analyze_instruction_un_op(IrAnalyze ira, IrInstruction	...	@@ -14550,11 +14551,18 @@ static IrInstruction ir_analyze_instruction_un_op(IrAnalyze ira, IrInstruction
14550	buf_ptr(&ptr_type->name)));	14551	buf_ptr(&ptr_type->name)));
14551	return ira->codegen->invalid_instruction;	14552	return ira->codegen->invalid_instruction;
14552	}	14553	}
14553	// this dereference is always an rvalue because in the IR gen we identify lvalue and emit	14554
14554	// one of the ptr instructions
14555	IrInstruction *result = ir_get_deref(ira, &instruction->base, ptr);	14555	IrInstruction *result = ir_get_deref(ira, &instruction->base, ptr);
14556	if (result == ira->codegen->invalid_instruction)	14556	if (result == ira->codegen->invalid_instruction)
14557	return ira->codegen->invalid_instruction;	14557	return ira->codegen->invalid_instruction;
		14558
		14559	// If the result needs to be an lvalue, type check it
		14560	if (instruction->lval == LValPtr && result->value.type->id != ZigTypeIdPointer) {
		14561	ir_add_error(ira, &instruction->base,
		14562	buf_sprintf("attempt to dereference non-pointer type '%s'", buf_ptr(&result->value.type->name)));
		14563	return ira->codegen->invalid_instruction;
		14564	}
		14565
14558	return result;	14566	return result;
14559	}	14567	}
14560	case IrUnOpOptional:	14568	case IrUnOpOptional:
...	@@ -15380,12 +15388,6 @@ static IrInstruction ir_analyze_instruction_field_ptr(IrAnalyze ira, IrInstruc	...	@@ -15380,12 +15388,6 @@ static IrInstruction ir_analyze_instruction_field_ptr(IrAnalyze ira, IrInstruc
15380	if (type_is_invalid(container_ptr->value.type))	15388	if (type_is_invalid(container_ptr->value.type))
15381	return ira->codegen->invalid_instruction;	15389	return ira->codegen->invalid_instruction;
15382		15390
15383	if (container_ptr->value.type->id != ZigTypeIdPointer) {
15384	ir_add_error_node(ira, field_ptr_instruction->base.source_node,
15385	buf_sprintf("attempt to dereference non-pointer type '%s'",
15386	buf_ptr(&container_ptr->value.type->name)));
15387	return ira->codegen->invalid_instruction;
15388	}
15389	ZigType *container_type = container_ptr->value.type->data.pointer.child_type;	15391	ZigType *container_type = container_ptr->value.type->data.pointer.child_type;
15390		15392
15391	Buf *field_name = field_ptr_instruction->field_name_buffer;	15393	Buf *field_name = field_ptr_instruction->field_name_buffer;
...	@@ -16596,11 +16598,6 @@ static IrInstruction ir_analyze_instruction_switch_target(IrAnalyze ira,	...	@@ -16596,11 +16598,6 @@ static IrInstruction ir_analyze_instruction_switch_target(IrAnalyze ira,
16596	return ir_const_type(ira, &switch_target_instruction->base, ptr_type->data.pointer.child_type);	16598	return ir_const_type(ira, &switch_target_instruction->base, ptr_type->data.pointer.child_type);
16597	}	16599	}
16598		16600
16599	if (target_value_ptr->value.type->id != ZigTypeIdPointer) {
16600	ir_add_error(ira, target_value_ptr, buf_sprintf("invalid deref on switch target"));
16601	return ira->codegen->invalid_instruction;
16602	}
16603
16604	ZigType *target_type = target_value_ptr->value.type->data.pointer.child_type;	16601	ZigType *target_type = target_value_ptr->value.type->data.pointer.child_type;
16605	ConstExprValue *pointee_val = nullptr;	16602	ConstExprValue *pointee_val = nullptr;
16606	if (instr_is_comptime(target_value_ptr)) {	16603	if (instr_is_comptime(target_value_ptr)) {

test/compile_errors.zig+21-3

 @@ -137,6 +137,24 @@ pub fn addCases(cases: *tests.CompileErrorContext) void {
         ".tmp_source.zig:3:15: error: C pointers cannot point to non-C-ABI-compatible type 'Foo'",
     );
+    cases.addTest(
+        "assign to invalid dereference",
+        \\export fn entry() void {
+        \\    'a'.* = 1;
+        \\}
+    ,
+        ".tmp_source.zig:2:8: error: attempt to dereference non-pointer type 'comptime_int'",
+    );
+    cases.addTest(
+        "take slice of invalid dereference",
+        \\export fn entry() void {
+        \\    const x = 'a'.*[0..];
+        \\}
+    ,
+        ".tmp_source.zig:2:18: error: attempt to dereference non-pointer type 'comptime_int'",
+    );
     cases.addTest(
         "@truncate undefined value",
         \\export fn entry() void {
 @@ -447,7 +465,7 @@ pub fn addCases(cases: *tests.CompileErrorContext) void {
         \\    _ = a.*.len;
         \\}
     ,
-        ".tmp_source.zig:3:12: error: attempt to dereference non-pointer type '[]u8'",
+        ".tmp_source.zig:3:10: error: attempt to dereference non-pointer type '[]u8'",
     );
     cases.add(
 @@ -1158,7 +1176,7 @@ pub fn addCases(cases: *tests.CompileErrorContext) void {
         \\    Filled,
         \\};
     ,
-        ".tmp_source.zig:3:17: error: invalid deref on switch target",
+        ".tmp_source.zig:3:17: error: attempt to dereference non-pointer type 'Tile'",
     );
     cases.add(
 @@ -4000,7 +4018,7 @@ pub fn addCases(cases: *tests.CompileErrorContext) void {
         \\
         \\export fn entry() usize { return @sizeOf(@typeOf(pass)); }
     ,
-        ".tmp_source.zig:4:10: error: attempt to dereference non pointer type '[10]u8'",
+        ".tmp_source.zig:4:10: error: attempt to dereference non-pointer type '[10]u8'",
     );
     cases.add(