Commit 3e79315d19c7dfe5f9b90185d8030209ef8dd829 | zig

author	Andrew Kelley <andrew@ziglang.org> 2023-09-18 21:24:50-07:00
committer	Andrew Kelley <andrew@ziglang.org> 2023-09-19 00:43:21-07:00
log	3e79315d19c7dfe5f9b90185d8030209ef8dd829
tree	28be901fb7fa95af1e73bd4c6b8297421b916570
parent	f91ff9a746ff97945dacc8114c073bd279f68f17

x86 backend: don't read bogus safety flag

Safety is not a global flag that should be enabled or disabled for all
stores - it's lowered by the frontend directly into AIR instruction
semantics. The flag for this is communicated via the `store` vs
`store_safe` AIR instructions, and whether to write 0xaa bytes or not
should be decided in `airStore` and passed down via function parameters.

This commit is a step backwards since it removes functionality but it
aims our feet towards a better mountain to climb.

3 files changed, 6 insertions(+), 16 deletions(-)

src
- arch
  - x86_64
    CodeGen.zig
test
- behavior
  - cast.zig
  - int128.zig

src/arch/x86_64/CodeGen.zig+3-15

 @@ -1934,7 +1934,7 @@ fn genBody(self: *Self, body: []const Air.Inst.Index) InnerError!void {
             .ptr_elem_ptr        => try self.airPtrElemPtr(inst),
             .inferred_alloc, .inferred_alloc_comptime => unreachable,
-            .unreach  => if (self.wantSafety()) try self.airTrap() else self.finishAirBookkeeping(),
+            .unreach  => self.finishAirBookkeeping(),
             .optional_payload           => try self.airOptionalPayload(inst),
             .optional_payload_ptr       => try self.airOptionalPayloadPtr(inst),
 @@ -9813,8 +9813,7 @@ fn genSetReg(self: *Self, dst_reg: Register, ty: Type, src_mcv: MCValue) InnerEr
         .register_overflow,
         .reserved_frame,
         => unreachable,
-        .undef => if (self.wantSafety())
+        .undef => {},
-            try self.genSetReg(dst_reg.to64(), Type.usize, .{ .immediate = 0xaaaaaaaaaaaaaaaa }),
         .eflags => |cc| try self.asmSetccRegister(dst_reg.to8(), cc),
         .immediate => |imm| {
             if (imm == 0) {
 @@ -10098,8 +10097,7 @@ fn genSetMem(self: *Self, base: Memory.Base, disp: i32, ty: Type, src_mcv: MCVal
     };
     switch (src_mcv) {
         .none, .unreach, .dead, .reserved_frame => unreachable,
-        .undef => if (self.wantSafety())
+        .undef => {},
-            try self.genInlineMemset(dst_ptr_mcv, .{ .immediate = 0xaa }, .{ .immediate = abi_size }),
         .immediate => |imm| switch (abi_size) {
             1, 2, 4 => {
                 const immediate = if (ty.isSignedInt(mod))
 @@ -12016,16 +12014,6 @@ fn resolveCallingConventionValues(
     return result;
 }
-/// TODO support scope overrides. Also note this logic is duplicated with `Module.wantSafety`.
-fn wantSafety(self: *Self) bool {
-    return switch (self.bin_file.options.optimize_mode) {
-        .Debug => true,
-        .ReleaseSafe => true,
-        .ReleaseFast => false,
-        .ReleaseSmall => false,
-    };
-}
 fn fail(self: *Self, comptime format: []const u8, args: anytype) InnerError {
     @setCold(true);
     assert(self.err_msg == null);

test/behavior/cast.zig+2-1

 @@ -334,10 +334,11 @@ test "*const ?[*]const T to [*c]const [*c]const T" {
     try expect(b[0][1] == 'k');
 }
-test "array coersion to undefined at runtime" {
+test "array coercion to undefined at runtime" {
     if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest;
     if (builtin.zig_backend == .stage2_sparc64) return error.SkipZigTest; // TODO
     if (builtin.zig_backend == .stage2_spirv64) return error.SkipZigTest;
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
     @setRuntimeSafety(true);

test/behavior/int128.zig+1

...	@@ -28,6 +28,7 @@ test "undefined 128 bit int" {	...	@@ -28,6 +28,7 @@ test "undefined 128 bit int" {
28	if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest; // TODO	28	if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest; // TODO
29	if (builtin.zig_backend == .stage2_sparc64) return error.SkipZigTest; // TODO	29	if (builtin.zig_backend == .stage2_sparc64) return error.SkipZigTest; // TODO
30	if (builtin.zig_backend == .stage2_spirv64) return error.SkipZigTest;	30	if (builtin.zig_backend == .stage2_spirv64) return error.SkipZigTest;
		31	if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
31		32
32	@setRuntimeSafety(true);	33	@setRuntimeSafety(true);
33		34