diff options
Diffstat (limited to 'src/check_expr.cpp')
| -rw-r--r-- | src/check_expr.cpp | 75 |
1 files changed, 73 insertions, 2 deletions
diff --git a/src/check_expr.cpp b/src/check_expr.cpp index db82a60ce..e0b6408e3 100644 --- a/src/check_expr.cpp +++ b/src/check_expr.cpp @@ -129,6 +129,8 @@ gb_internal bool check_is_castable_to(CheckerContext *c, Operand *operand, Type gb_internal bool is_exact_value_zero(ExactValue const &v); +gb_internal IntegerDivisionByZeroKind check_for_integer_division_by_zero(CheckerContext *c, Ast *node); + enum LoadDirectiveResult { LoadDirective_Success = 0, LoadDirective_Error = 1, @@ -4309,7 +4311,25 @@ gb_internal void check_binary_expr(CheckerContext *c, Operand *x, Ast *node, Typ } if (fail) { - error(y->expr, "Division by zero not allowed"); + if (is_type_integer(x->type) || (x->mode == Addressing_Constant && x->value.kind == ExactValue_Integer)) { + if (check_for_integer_division_by_zero(c, node) != IntegerDivisionByZero_Trap) { + // Okay + break; + } + } + + switch (op.kind) { + case Token_Mod: + case Token_ModMod: + case Token_ModEq: + case Token_ModModEq: + error(y->expr, "Division by zero through '%.*s' not allowed", LIT(token_strings[op.kind])); + break; + case Token_Quo: + case Token_QuoEq: + error(y->expr, "Division by zero not allowed"); + break; + } x->mode = Addressing_Invalid; return; } @@ -4349,7 +4369,43 @@ gb_internal void check_binary_expr(CheckerContext *c, Operand *x, Ast *node, Typ } } - x->value = exact_binary_operator_value(op.kind, a, b); + match_exact_values(&a, &b); + + + IntegerDivisionByZeroKind zero_behaviour = check_for_integer_division_by_zero(c, node); + if (zero_behaviour != IntegerDivisionByZero_Trap && + b.kind == ExactValue_Integer && big_int_is_zero(&b.value_integer) && + (op.kind == Token_QuoEq || op.kind == Token_Mod || op.kind == Token_ModMod)) { + if (op.kind == Token_QuoEq) { + if (zero_behaviour == IntegerDivisionByZero_Zero) { + // x/0 == 0 + x->value = b; + } else { + // x/0 == x + x->value = a; + } + } else { + /* + NOTE(bill): @integer division by zero rules + + truncated: r = a - b*trunc(a/b) + floored: r = a - b*floor(a/b) + + IFF a/0 == 0, then (a%0 == a) or (a%%0 == a) + IFF a/0 == a, then (a%0 == 0) or (a%%0 == 0) + */ + + if (zero_behaviour == IntegerDivisionByZero_Zero) { + // x%0 == x + x->value = a; + } else { + // x%0 == 0 + x->value = b; + } + } + } else { + x->value = exact_binary_operator_value(op.kind, a, b); + } if (is_type_typed(x->type)) { if (node != nullptr) { @@ -9602,6 +9658,21 @@ gb_internal bool check_for_dynamic_literals(CheckerContext *c, Ast *node, AstCom return cl->elems.count > 0; } +gb_internal IntegerDivisionByZeroKind check_for_integer_division_by_zero(CheckerContext *c, Ast *node) { + // TODO(bill): per file `#+feature` flags + u64 flags = check_feature_flags(c, node); + if ((flags & OptInFeatureFlag_IntegerDivisionByZero_Trap) != 0) { + return IntegerDivisionByZero_Trap; + } + if ((flags & OptInFeatureFlag_IntegerDivisionByZero_Zero) != 0) { + return IntegerDivisionByZero_Zero; + } + if ((flags & OptInFeatureFlag_IntegerDivisionByZero_Self) != 0) { + return IntegerDivisionByZero_Self; + } + return build_context.integer_division_by_zero_behaviour; +} + gb_internal ExprKind check_compound_literal(CheckerContext *c, Operand *o, Ast *node, Type *type_hint) { ExprKind kind = Expr_Expr; ast_node(cl, CompoundLit, node); |