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Fix lvalue dereference type checking

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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.
This commit is contained in:
Matthew McAllister
2019-02-12 21:22:16 -08:00
parent c3c92ca8b1
commit 91989e70ba
3 changed files with 45 additions and 29 deletions
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39
src/ir.cpp
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@@ -1307,6 +1307,7 @@ static IrInstruction *ir_build_un_op(IrBuilder *irb, Scope *scope, AstNode *sour
IrInstructionUnOp *br_instruction = ir_build_instruction<IrInstructionUnOp>(irb, scope, source_node);
br_instruction->op_id = op_id;
br_instruction->value = value;
br_instruction->lval = LValNone;
ir_ref_instruction(value, irb->current_basic_block);
@@ -7223,7 +7224,13 @@ static IrInstruction *ir_gen_node_raw(IrBuilder *irb, AstNode *node, Scope *scop
if (value == irb->codegen->invalid_instruction)
return value;
return ir_build_un_op(irb, scope, node, IrUnOpDereference, value);
// We essentially just converted any lvalue from &(x.*) to (&x).*;
// this inhibits checking that x is a pointer later, so we directly
// record whether the pointer check is needed
IrInstructionUnOp *result = (IrInstructionUnOp*)ir_build_un_op(irb, scope, node, IrUnOpDereference, value);
result->lval = lval;
return &result->base;
}
case NodeTypeUnwrapOptional: {
AstNode *expr_node = node->data.unwrap_optional.expr;
@@ -11437,7 +11444,7 @@ static IrInstruction *ir_get_deref(IrAnalyze *ira, IrInstruction *source_instruc
return load_ptr_instruction;
} else {
ir_add_error_node(ira, source_instruction->source_node,
buf_sprintf("attempt to dereference non pointer type '%s'",
buf_sprintf("attempt to dereference non-pointer type '%s'",
buf_ptr(&type_entry->name)));
return ira->codegen->invalid_instruction;
}
@@ -13616,12 +13623,6 @@ no_mem_slot:
static IrInstruction *ir_analyze_store_ptr(IrAnalyze *ira, IrInstruction *source_instr,
IrInstruction *ptr, IrInstruction *uncasted_value)
{
if (ptr->value.type->id != ZigTypeIdPointer) {
ir_add_error(ira, ptr,
buf_sprintf("attempt to dereference non pointer type '%s'", buf_ptr(&ptr->value.type->name)));
return ira->codegen->invalid_instruction;
}
if (ptr->value.data.x_ptr.special == ConstPtrSpecialDiscard) {
return ir_const_void(ira, source_instr);
}
@@ -14550,11 +14551,18 @@ static IrInstruction *ir_analyze_instruction_un_op(IrAnalyze *ira, IrInstruction
buf_ptr(&ptr_type->name)));
return ira->codegen->invalid_instruction;
}
// this dereference is always an rvalue because in the IR gen we identify lvalue and emit
// one of the ptr instructions
IrInstruction *result = ir_get_deref(ira, &instruction->base, ptr);
if (result == ira->codegen->invalid_instruction)
return ira->codegen->invalid_instruction;
// If the result needs to be an lvalue, type check it
if (instruction->lval == LValPtr && result->value.type->id != ZigTypeIdPointer) {
ir_add_error(ira, &instruction->base,
buf_sprintf("attempt to dereference non-pointer type '%s'", buf_ptr(&result->value.type->name)));
return ira->codegen->invalid_instruction;
}
return result;
}
case IrUnOpOptional:
@@ -15380,12 +15388,6 @@ static IrInstruction *ir_analyze_instruction_field_ptr(IrAnalyze *ira, IrInstruc
if (type_is_invalid(container_ptr->value.type))
return ira->codegen->invalid_instruction;
if (container_ptr->value.type->id != ZigTypeIdPointer) {
ir_add_error_node(ira, field_ptr_instruction->base.source_node,
buf_sprintf("attempt to dereference non-pointer type '%s'",
buf_ptr(&container_ptr->value.type->name)));
return ira->codegen->invalid_instruction;
}
ZigType *container_type = container_ptr->value.type->data.pointer.child_type;
Buf *field_name = field_ptr_instruction->field_name_buffer;
@@ -16596,11 +16598,6 @@ static IrInstruction *ir_analyze_instruction_switch_target(IrAnalyze *ira,
return ir_const_type(ira, &switch_target_instruction->base, ptr_type->data.pointer.child_type);
}
if (target_value_ptr->value.type->id != ZigTypeIdPointer) {
ir_add_error(ira, target_value_ptr, buf_sprintf("invalid deref on switch target"));
return ira->codegen->invalid_instruction;
}
ZigType *target_type = target_value_ptr->value.type->data.pointer.child_type;
ConstExprValue *pointee_val = nullptr;
if (instr_is_comptime(target_value_ptr)) {