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make it an error to ignore a statement's value 

this makes {1;} an error.
master
Josh Wolfe 2017-04-12 16:49:47 -07:00
parent bf67427c67
commit 919910312d
3 changed files with 36 additions and 28 deletions
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17
src/analyze.cpp
View File

@ -2987,23 +2987,6 @@ void semantic_analyze(CodeGen *g) {
}
}
bool is_node_void_expr(AstNode *node) {
if (node->type == NodeTypeContainerInitExpr &&
node->data.container_init_expr.kind == ContainerInitKindArray)
{
AstNode *type_node = node->data.container_init_expr.type;
if (type_node->type == NodeTypeSymbol &&
buf_eql_str(type_node->data.symbol_expr.symbol, "void"))
{
return true;
}
} else if (node->type == NodeTypeBlock && node->data.block.statements.length == 0) {
return true;
}
return false;
}
TypeTableEntry **get_int_type_ptr(CodeGen *g, bool is_signed, uint32_t size_in_bits) {
size_t index;
if (size_in_bits == 8) {

1
src/analyze.hpp
View File

@ -17,7 +17,6 @@ TypeTableEntry *new_type_table_entry(TypeTableEntryId id);
TypeTableEntry *get_pointer_to_type(CodeGen *g, TypeTableEntry *child_type, bool is_const);
TypeTableEntry *get_pointer_to_type_extra(CodeGen *g, TypeTableEntry *child_type, bool is_const,
bool is_volatile, uint32_t bit_offset, uint32_t unaligned_bit_count);
bool is_node_void_expr(AstNode *node);
uint64_t type_size(CodeGen *g, TypeTableEntry *type_entry);
uint64_t type_size_bits(CodeGen *g, TypeTableEntry *type_entry);
TypeTableEntry **get_int_type_ptr(CodeGen *g, bool is_signed, uint32_t size_in_bits);

46
src/ir.cpp
View File

@ -3344,6 +3344,7 @@ static IrInstruction *ir_gen_block(IrBuilder *irb, Scope *parent_scope, AstNode
return ir_mark_gen(ir_build_const_void(irb, child_scope, block_node));
}
bool is_continuation_unreachable = false;
IrInstruction *return_value = nullptr;
for (size_t i = 0; i < block_node->data.block.statements.length; i += 1) {
AstNode *statement_node = block_node->data.block.statements.at(i);
@ -3367,7 +3368,7 @@ static IrInstruction *ir_gen_block(IrBuilder *irb, Scope *parent_scope, AstNode
scope_block->label_table.put(label_name, label);
}
if (!(return_value && instr_is_unreachable(return_value))) {
if (!is_continuation_unreachable) {
// fall through into new labeled basic block
IrInstruction *is_comptime = ir_mark_gen(ir_build_const_bool(irb, child_scope, statement_node,
ir_should_inline(irb->exec, child_scope)));
@ -3375,33 +3376,58 @@ static IrInstruction *ir_gen_block(IrBuilder *irb, Scope *parent_scope, AstNode
}
ir_set_cursor_at_end(irb, label_block);
return_value = nullptr;
// a label is an entry point
is_continuation_unreachable = false;
continue;
}
if (return_value && instr_is_unreachable(return_value)) {
if (is_node_void_expr(statement_node))
if (is_continuation_unreachable) {
// if you put a semicolon after a return statement,
// then we get a void statement in the unreachable area.
// this is fine. ignore any void blocks we get from this happening.
if (statement_node->type == NodeTypeBlock && statement_node->data.block.statements.length == 0)
continue;
add_node_error(irb->codegen, statement_node, buf_sprintf("unreachable code"));
}
return_value = ir_gen_node(irb, statement_node, child_scope);
if (statement_node->type == NodeTypeDefer && return_value != irb->codegen->invalid_instruction) {
IrInstruction *statement_value = ir_gen_node(irb, statement_node, child_scope);
is_continuation_unreachable = instr_is_unreachable(statement_value);
if (is_continuation_unreachable)
return_value = statement_value;
else
return_value = nullptr;
if (statement_node->type == NodeTypeDefer && statement_value != irb->codegen->invalid_instruction) {
// defer starts a new scope
child_scope = statement_node->data.defer.child_scope;
assert(child_scope);
} else if (return_value->id == IrInstructionIdDeclVar) {
} else if (statement_value->id == IrInstructionIdDeclVar) {
// variable declarations start a new scope
IrInstructionDeclVar *decl_var_instruction = (IrInstructionDeclVar *)return_value;
IrInstructionDeclVar *decl_var_instruction = (IrInstructionDeclVar *)statement_value;
child_scope = decl_var_instruction->var->child_scope;
} else {
// label, defer, variable declaration will never be the last statement
if (i == block_node->data.block.statements.length - 1) {
// this is the result value statement
return_value = statement_value;
} else {
// there are more statements ahead of this one. this statement's value must be void
TypeTableEntry *instruction_type = statement_value->value.type;
if (instruction_type &&
instruction_type->id != TypeTableEntryIdInvalid &&
instruction_type->id != TypeTableEntryIdVoid &&
instruction_type->id != TypeTableEntryIdUnreachable) {
add_node_error(irb->codegen, statement_node, buf_sprintf("expression valued ignored"));
}
}
}
}
// labels are never the last statement
assert(return_value != nullptr);
if (!instr_is_unreachable(return_value))
if (!is_continuation_unreachable) {
// control flow falls out of block
ir_gen_defers_for_block(irb, child_scope, outer_block_scope, false, false);
}
return return_value;
}