zig

commit e6b3cb5043b189fab6417df4a6921728ea174c8f (tree)
parent 8c4faa5f3f63cfbcfdc12cda7c37be1da642d2f6
Author: Veikka Tuominen <git@vexu.eu>
Date:   Fri,  4 Nov 2022 16:07:13 +0200

Sema: detect division overflow

Closes #13434

Diffstat:
M
src/Sema.zig
 | 
30
++++++++++++++++++------------
A
test/cases/compile_errors/div_overflow.zig
 | 
11
+++++++++++

2 files changed, 29 insertions(+), 12 deletions(-)
diff --git a/src/Sema.zig b/src/Sema.zig
@@ -12469,10 +12469,12 @@ fn zirDiv(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError!Air.Ins
 
             if (maybe_rhs_val) |rhs_val| {
                 if (is_int) {
-                    return sema.addConstant(
-                        resolved_type,
-                        try lhs_val.intDiv(rhs_val, resolved_type, sema.arena, target),
-                    );
+                    const res = try lhs_val.intDiv(rhs_val, resolved_type, sema.arena, target);
+                    var vector_index: usize = undefined;
+                    if (!(try sema.intFitsInType(block, src, res, resolved_type, &vector_index))) {
+                        return sema.failWithIntegerOverflow(block, src, resolved_type, res, vector_index);
+                    }
+                    return sema.addConstant(resolved_type, res);
                 } else {
                     return sema.addConstant(
                         resolved_type,
@@ -12584,10 +12586,12 @@ fn zirDivExact(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError!Ai
                     if (modulus_val.compareWithZero(.neq)) {
                         return sema.fail(block, src, "exact division produced remainder", .{});
                     }
-                    return sema.addConstant(
-                        resolved_type,
-                        try lhs_val.intDiv(rhs_val, resolved_type, sema.arena, target),
-                    );
+                    const res = try lhs_val.intDiv(rhs_val, resolved_type, sema.arena, target);
+                    var vector_index: usize = undefined;
+                    if (!(try sema.intFitsInType(block, src, res, resolved_type, &vector_index))) {
+                        return sema.failWithIntegerOverflow(block, src, resolved_type, res, vector_index);
+                    }
+                    return sema.addConstant(resolved_type, res);
                 } else {
                     const modulus_val = try lhs_val.floatMod(rhs_val, resolved_type, sema.arena, target);
                     if (modulus_val.compareWithZero(.neq)) {
@@ -12862,10 +12866,12 @@ fn zirDivTrunc(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError!Ai
 
             if (maybe_rhs_val) |rhs_val| {
                 if (is_int) {
-                    return sema.addConstant(
-                        resolved_type,
-                        try lhs_val.intDiv(rhs_val, resolved_type, sema.arena, target),
-                    );
+                    const res = try lhs_val.intDiv(rhs_val, resolved_type, sema.arena, target);
+                    var vector_index: usize = undefined;
+                    if (!(try sema.intFitsInType(block, src, res, resolved_type, &vector_index))) {
+                        return sema.failWithIntegerOverflow(block, src, resolved_type, res, vector_index);
+                    }
+                    return sema.addConstant(resolved_type, res);
                 } else {
                     return sema.addConstant(
                         resolved_type,
diff --git a/test/cases/compile_errors/div_overflow.zig b/test/cases/compile_errors/div_overflow.zig
@@ -0,0 +1,11 @@
+comptime {
+    const a = -128;
+    const b: i8 = -1;
+    _ = a / b;
+}
+
+// error
+// backend=stage2
+// target=native
+//
+// :4:11: error: overflow of integer type 'i8' with value '128'