Commit aa0906e9aaaf36bc928b5502bdb34e7a0409b2c0 | zig

author	Joachim Schmidt <joachim.schmidt557@outlook.com> 2021-01-02 18:53:11+01:00
committer	Andrew Kelley <andrew@ziglang.org> 2021-01-03 19:54:12-08:00
log	aa0906e9aaaf36bc928b5502bdb34e7a0409b2c0
tree	d6f669cebdae86ea204b4db4086cdd44bdcc8b87
parent	4400d2d7abb3be8c7b9fde9754fc58d4510c5107

stage2 x86_64: fix bug in Function.gen

Previously, the x86_64 backend would remove code for exitlude relocs
if the jump amount were 0. This causes issues as earlier jumps rely on
the jump being present at the same address.

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

src
- codegen.zig

src/codegen.zig+3-6

 @@ -543,13 +543,10 @@ fn Function(comptime arch: std.Target.Cpu.Arch) type {
                         if (self.code.items.len >= math.maxInt(i32)) {
                             return self.fail(self.src, "unable to perform relocation: jump too far", .{});
                         }
-                        for (self.exitlude_jump_relocs.items) |jmp_reloc| {
+                        if (self.exitlude_jump_relocs.items.len == 1) {
+                            self.code.items.len -= 5;
+                        } else for (self.exitlude_jump_relocs.items) |jmp_reloc| {
                             const amt = self.code.items.len - (jmp_reloc + 4);
-                            // If it wouldn't jump at all, elide it.
-                            if (amt == 0) {
-                                self.code.items.len -= 5;
-                                continue;
-                            }
                             const s32_amt = @intCast(i32, amt);
                             mem.writeIntLittle(i32, self.code.items[jmp_reloc..][0..4], s32_amt);
                         }