From 6e2622661cdf9dd48cf962e5d6902324b15468c3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?S=C3=A9bastien=20Marie?= <semarie@online.fr>
Date: Wed, 23 Dec 2020 12:39:20 +0000
Subject: [PATCH] openbsd: implement segfault handling on openbsd x86_64

---
 lib/std/debug.zig           |  5 +++-
 lib/std/os/bits/openbsd.zig | 54 +++++++++++++++++++++++++++++++++++++
 2 files changed, 58 insertions(+), 1 deletion(-)

diff --git a/lib/std/debug.zig b/lib/std/debug.zig
index e93143c598..7284237cb2 100644
--- a/lib/std/debug.zig
+++ b/lib/std/debug.zig
@@ -1696,7 +1696,7 @@ fn getDebugInfoAllocator() *mem.Allocator {
 pub const have_segfault_handling_support = switch (builtin.os.tag) {
     .linux, .netbsd => true,
     .windows => true,
-    .freebsd => @hasDecl(os, "ucontext_t"),
+    .freebsd, .openbsd => @hasDecl(os, "ucontext_t"),
     else => false,
 };
 pub const enable_segfault_handler: bool = if (@hasDecl(root, "enable_segfault_handler"))
@@ -1760,6 +1760,7 @@ fn handleSegfaultLinux(sig: i32, info: *const os.siginfo_t, ctx_ptr: ?*const c_v
         .linux => @ptrToInt(info.fields.sigfault.addr),
         .freebsd => @ptrToInt(info.addr),
         .netbsd => @ptrToInt(info.info.reason.fault.addr),
+        .openbsd => @ptrToInt(info.data.fault.addr),
         else => unreachable,
     };
 
@@ -1786,10 +1787,12 @@ fn handleSegfaultLinux(sig: i32, info: *const os.siginfo_t, ctx_ptr: ?*const c_v
             const ip = switch (builtin.os.tag) {
                 .linux, .netbsd => @intCast(usize, ctx.mcontext.gregs[os.REG_RIP]),
                 .freebsd => @intCast(usize, ctx.mcontext.rip),
+                .openbsd => @intCast(usize, ctx.sc_rip),
                 else => unreachable,
             };
             const bp = switch (builtin.os.tag) {
                 .linux, .netbsd => @intCast(usize, ctx.mcontext.gregs[os.REG_RBP]),
+                .openbsd => @intCast(usize, ctx.sc_rbp),
                 .freebsd => @intCast(usize, ctx.mcontext.rbp),
                 else => unreachable,
             };
diff --git a/lib/std/os/bits/openbsd.zig b/lib/std/os/bits/openbsd.zig
index a9ab929a42..c84a6de01a 100644
--- a/lib/std/os/bits/openbsd.zig
+++ b/lib/std/os/bits/openbsd.zig
@@ -809,6 +809,60 @@ comptime {
         std.debug.assert(@sizeOf(siginfo_t) == 136);
 }
 
+pub usingnamespace switch (builtin.arch) {
+    .x86_64 => struct {
+        pub const ucontext_t = extern struct {
+            sc_rdi: c_long,
+            sc_rsi: c_long,
+            sc_rdx: c_long,
+            sc_rcx: c_long,
+            sc_r8: c_long,
+            sc_r9: c_long,
+            sc_r10: c_long,
+            sc_r11: c_long,
+            sc_r12: c_long,
+            sc_r13: c_long,
+            sc_r14: c_long,
+            sc_r15: c_long,
+            sc_rbp: c_long,
+            sc_rbx: c_long,
+            sc_rax: c_long,
+            sc_gs: c_long,
+            sc_fs: c_long,
+            sc_es: c_long,
+            sc_ds: c_long,
+            sc_trapno: c_long,
+            sc_err: c_long,
+            sc_rip: c_long,
+            sc_cs: c_long,
+            sc_rflags: c_long,
+            sc_rsp: c_long,
+            sc_ss: c_long,
+
+            sc_fpstate: fxsave64,
+            __sc_unused: c_int,
+            sc_mask: c_int,
+            sc_cookie: c_long,
+        };
+
+        pub const fxsave64 = packed struct {
+            fx_fcw: u16,
+            fx_fsw: u16,
+            fx_ftw: u8,
+            fx_unused1: u8,
+            fx_fop: u16,
+            fx_rip: u64,
+            fx_rdp: u64,
+            fx_mxcsr: u32,
+            fx_mxcsr_mask: u32,
+            fx_st: [8][2]u64,
+            fx_xmm: [16][2]u64,
+            fx_unused3: [96]u8,
+        };
+    },
+    else => struct {},
+};
+
 pub const sigset_t = c_uint;
 pub const empty_sigset: sigset_t = 0;