srctree

Techatrix parent 4ace1f5a ec358d6d
sema: fix safe integer arithmetic operations on undefined values

Previously @as(i64, undefined) +% 1 would produce @as(@TypeOf(undefined), undefined) which now gives @as(i64, undefined).Previously @as(i64, undefined) +| 1 would hit an assertion which now gives @as(i64, undefined).

inline split

src/Sema.zig added: 271, removed: 25, total 246

@@ -16140,6 +16140,10 @@ fn analyzeArithmetic(

return casted_lhs;

}

if (maybe_lhs_val) |lhs_val| {

if (lhs_val.isUndef(mod)) {

return mod.undefRef(resolved_type);

}

const val = if (scalar_tag == .ComptimeInt)

try sema.intAdd(lhs_val, rhs_val, resolved_type, undefined)

else

@@ -16202,7 +16206,7 @@ fn analyzeArithmetic(

.subwrap => {

// Integers only; floats are checked above.

// If the RHS is zero, then the other operand is returned, even if it is undefined.

// If the RHS is zero, then the LHS is returned, even if it is undefined.

// If either of the operands are undefined, the result is undefined.

if (maybe_rhs_val) |rhs_val| {

if (rhs_val.isUndef(mod)) {

@@ -16223,8 +16227,8 @@ fn analyzeArithmetic(

.sub_sat => {

// Integers only; floats are checked above.

// If the RHS is zero, result is LHS.

// If either of the operands are undefined, result is undefined.

// If the RHS is zero, then the LHS is returned, even if it is undefined.

// If either of the operands are undefined, the result is undefined.

if (maybe_rhs_val) |rhs_val| {

if (rhs_val.isUndef(mod)) {

return mod.undefRef(resolved_type);

@@ -16255,7 +16259,9 @@ fn analyzeArithmetic(

// If either of the operands are undefined, it's a compile error

// because there is a possible value for which the addition would

// overflow (max_int), causing illegal behavior.

// For floats: either operand being undef makes the result undef.

// For floats:

// If either of the operands are undefined, the result is undefined.

// If either of the operands are inf, and the other operand is zero,

// the result is nan.

// If either of the operands are nan, the result is nan.

@@ -38093,7 +38099,7 @@ fn numberAddWrapScalar(

ty: Type,

) !Value {

const mod = sema.mod;

if (lhs.isUndef(mod) or rhs.isUndef(mod)) return Value.undef;

if (lhs.isUndef(mod) or rhs.isUndef(mod)) return mod.undefValue(ty);

if (ty.zigTypeTag(mod) == .ComptimeInt) {

return sema.intAdd(lhs, rhs, ty, undefined);

@@ -38183,7 +38189,7 @@ fn numberSubWrapScalar(

ty: Type,

) !Value {

const mod = sema.mod;

if (lhs.isUndef(mod) or rhs.isUndef(mod)) return Value.undef;

if (lhs.isUndef(mod) or rhs.isUndef(mod)) return mod.undefValue(ty);

if (ty.zigTypeTag(mod) == .ComptimeInt) {

return sema.intSub(lhs, rhs, ty, undefined);

test/cases/compile_errors/add_on_undefined_value.zig added: 271, removed: 25, total 246

@@ -1,10 +1,24 @@

comptime {

const a: i64 = undefined;

_ = a + a;

const undef: i64 = undefined;

const not_undef: i64 = 32;

// If either of the operands are zero, then the other operand is returned.

@compileLog(undef + 0);

@compileLog(not_undef + 0);

@compileLog(0 + undef);

@compileLog(0 + not_undef);

_ = undef + undef;

}

// error

// backend=stage2

// target=native

// :3:13: error: use of undefined value here causes undefined behavior

// :11:17: error: use of undefined value here causes undefined behavior

// Compile Log Output:

// @as(i64, undefined)

// @as(i64, 32)

// @as(i64, undefined)

// @as(i64, 32)

filename was Deleted added: 271, removed: 25, total 246

@@ -0,0 +1,31 @@

comptime {

const undef: i64 = undefined;

const not_undef: i64 = 32;

// If either of the operands are zero, then the other operand is returned.

@compileLog(undef +| 0);

@compileLog(not_undef +| 0);

@compileLog(0 +| undef);

@compileLog(0 +| not_undef);

// If either of the operands are undefined, the result is undefined.

@compileLog(undef +| 1);

@compileLog(not_undef +| 1);

@compileLog(1 +| undef);

@compileLog(1 +| not_undef);

}

// error

// backend=stage2

// target=native

// :6:5: error: found compile log statement

// Compile Log Output:

// @as(i64, undefined)

// @as(i64, 32)

// @as(i64, undefined)

// @as(i64, 32)

// @as(i64, undefined)

// @as(i64, 33)

// @as(i64, undefined)

// @as(i64, 33)

filename was Deleted added: 271, removed: 25, total 246

@@ -0,0 +1,31 @@

comptime {

const undef: i64 = undefined;

const not_undef: i64 = 32;

// If either of the operands are zero, then the other operand is returned.

@compileLog(undef +% 0);

@compileLog(not_undef +% 0);

@compileLog(0 +% undef);

@compileLog(0 +% not_undef);

// If either of the operands are undefined, the result is undefined.

@compileLog(undef +% 1);

@compileLog(not_undef +% 1);

@compileLog(1 +% undef);

@compileLog(1 +% not_undef);

}

// error

// backend=stage2

// target=native

// :6:5: error: found compile log statement

// Compile Log Output:

// @as(i64, undefined)

// @as(i64, 32)

// @as(i64, undefined)

// @as(i64, 32)

// @as(i64, undefined)

// @as(i64, 33)

// @as(i64, undefined)

// @as(i64, 33)

test/cases/compile_errors/mult_on_undefined_value.zig added: 271, removed: 25, total 246

@@ -1,10 +1,38 @@

comptime {

const a: i64 = undefined;

_ = a * a;

const undef: i64 = undefined;

const not_undef: i64 = 32;

// If either of the operands are zero, the result is zero.

@compileLog(undef * 0);

@compileLog(not_undef * 0);

@compileLog(0 * undef);

@compileLog(0 * not_undef);

// If either of the operands are one, the result is the other

// operand, even if it is undefined.

@compileLog(undef * 1);

@compileLog(not_undef * 1);

@compileLog(1 * undef);

@compileLog(1 * not_undef);

// If either of the operands are undefined, it's a compile error

// because there is a possible value for which the addition would

// overflow (max_int), causing illegal behavior.

_ = undef * undef;

}

// error

// backend=stage2

// target=native

// :3:13: error: use of undefined value here causes undefined behavior

// :21:17: error: use of undefined value here causes undefined behavior

// Compile Log Output:

// @as(i64, 0)

// @as(i64, undefined)

// @as(i64, 32)

// @as(i64, undefined)

// @as(i64, 32)

filename was Deleted added: 271, removed: 25, total 246

@@ -0,0 +1,38 @@

comptime {

const undef: i64 = undefined;

const not_undef: i64 = 32;

// If either of the operands are zero, the result is zero.

@compileLog(undef *| 0);

@compileLog(not_undef *| 0);

@compileLog(0 *| undef);

@compileLog(0 *| not_undef);

// If either of the operands are one, result is the other operand.

@compileLog(undef *| 1);

@compileLog(not_undef *| 1);

@compileLog(1 *| undef);

@compileLog(1 *| not_undef);

// If either of the operands are undefined, result is undefined.

@compileLog(undef *| 2);

@compileLog(2 *| undef);

}

// error

// backend=stage2

// target=native

// :6:5: error: found compile log statement

// Compile Log Output:

// @as(i64, 0)

// @as(i64, undefined)

// @as(i64, 32)

// @as(i64, undefined)

// @as(i64, 32)

// @as(i64, undefined)

filename was Deleted added: 271, removed: 25, total 246

@@ -0,0 +1,38 @@

comptime {

const undef: i64 = undefined;

const not_undef: i64 = 32;

// If either of the operands are zero, the result is zero.

@compileLog(undef *% 0);

@compileLog(not_undef *% 0);

@compileLog(0 *% undef);

@compileLog(0 *% not_undef);

// If either of the operands are one, result is the other operand.

@compileLog(undef *% 1);

@compileLog(not_undef *% 1);

@compileLog(1 *% undef);

@compileLog(1 *% not_undef);

// If either of the operands are undefined, result is undefined.

@compileLog(undef *% 2);

@compileLog(2 *% undef);

}

// error

// backend=stage2

// target=native

// :6:5: error: found compile log statement

// Compile Log Output:

// @as(i64, 0)

// @as(i64, undefined)

// @as(i64, 32)

// @as(i64, undefined)

// @as(i64, 32)

// @as(i64, undefined)

test/cases/compile_errors/sub_on_undefined_value.zig added: 271, removed: 25, total 246

@@ -1,10 +1,20 @@

comptime {

const a: i64 = undefined;

_ = a - a;

const undef: i64 = undefined;

const not_undef: i64 = 32;

// If the rhs is zero, then the other operand is returned, even if it is undefined.

@compileLog(undef - 0);

@compileLog(not_undef - 0);

_ = undef - undef;

}

// error

// backend=stage2

// target=native

// :3:13: error: use of undefined value here causes undefined behavior

// :9:17: error: use of undefined value here causes undefined behavior

// Compile Log Output:

// @as(i64, undefined)

// @as(i64, 32)

filename was Deleted added: 271, removed: 25, total 246

@@ -0,0 +1,25 @@

comptime {

const undef: i64 = undefined;

const not_undef: i64 = 32;

// If the RHS is zero, then the LHS is returned, even if it is undefined.

@compileLog(undef -| 0);

@compileLog(not_undef -| 0);

// If either of the operands are undefined, the result is undefined.

@compileLog(undef -| not_undef);

@compileLog(not_undef -| undef);

@compileLog(undef -| undef);

}

// error

// backend=stage2

// target=native

// :6:5: error: found compile log statement

// Compile Log Output:

// @as(i64, undefined)

// @as(i64, 32)

// @as(i64, undefined)

filename was Deleted added: 271, removed: 25, total 246

@@ -0,0 +1,25 @@

comptime {

const undef: i64 = undefined;

const not_undef: i64 = 32;

// If the RHS is zero, then the LHS is returned, even if it is undefined.

@compileLog(undef -% 0);

@compileLog(not_undef -% 0);

// If either of the operands are undefined, the result is undefined.

@compileLog(undef -% not_undef);

@compileLog(not_undef -% undef);

@compileLog(undef -% undef);

}

// error

// backend=stage2

// target=native

// :6:5: error: found compile log statement

// Compile Log Output:

// @as(i64, undefined)

// @as(i64, 32)

// @as(i64, undefined)