std.os.linux: Don't emit CFI directives if unwind tables are disabled.

lib/std/os/linux/aarch64.zig

@@ -1,3 +1,4 @@
+const builtin = @import("builtin");
 const std = @import("../../std.zig");
 const maxInt = std.math.maxInt;
 const linux = std.os.linux;
@@ -122,7 +123,12 @@ pub fn clone() callconv(.Naked) usize {
         \\      ret
         \\
         \\      // child
-        \\1:    .cfi_undefined lr
+        \\1:
+    );
+    if (builtin.unwind_tables != .none or !builtin.strip_debug_info) asm volatile (
+        \\     .cfi_undefined lr
+    );
+    asm volatile (
         \\      mov fp, 0
         \\      mov lr, 0
         \\

lib/std/os/linux/hexagon.zig

@@ -1,3 +1,4 @@
+const builtin = @import("builtin");
 const std = @import("../../std.zig");
 const iovec = std.posix.iovec;
 const iovec_const = std.posix.iovec_const;
@@ -117,8 +118,11 @@ pub fn clone() callconv(.Naked) usize {
         \\
         \\ p0 = cmp.eq(r0, #0)
         \\ if (!p0) dealloc_return
-        \\
+    );
+    if (builtin.unwind_tables != .none or !builtin.strip_debug_info) asm volatile (
         \\ .cfi_undefined r31
+    );
+    asm volatile (
         \\ r30 = #0
         \\ r31 = #0
         \\

lib/std/os/linux/loongarch64.zig

@@ -1,3 +1,4 @@
+const builtin = @import("builtin");
 const std = @import("../../std.zig");
 const linux = std.os.linux;
 const SYS = linux.SYS;
@@ -121,7 +122,11 @@ pub fn clone() callconv(.Naked) usize {
         \\ beqz    $a0, 1f         # whether child process
         \\ jirl    $zero, $ra, 0   # parent process return
         \\1:
+    );
+    if (builtin.unwind_tables != .none or !builtin.strip_debug_info) asm volatile (
         \\ .cfi_undefined 1
+    );
+    asm volatile (
         \\ move    $fp, $zero
         \\ move    $ra, $zero
         \\

lib/std/os/linux/mips.zig

@@ -1,3 +1,4 @@
+const builtin = @import("builtin");
 const std = @import("../../std.zig");
 const maxInt = std.math.maxInt;
 const linux = std.os.linux;
@@ -231,7 +232,11 @@ pub fn clone() callconv(.Naked) usize {
         \\  jr $ra
         \\  nop
         \\1:
+    );
+    if (builtin.unwind_tables != .none or !builtin.strip_debug_info) asm volatile (
         \\  .cfi_undefined $ra
+    );
+    asm volatile (
         \\  move $fp, $zero
         \\  move $ra, $zero
         \\

lib/std/os/linux/mips64.zig

@@ -1,3 +1,4 @@
+const builtin = @import("builtin");
 const std = @import("../../std.zig");
 const maxInt = std.math.maxInt;
 const linux = std.os.linux;
@@ -210,7 +211,11 @@ pub fn clone() callconv(.Naked) usize {
         \\ jr $ra
         \\ nop
         \\1:
+    );
+    if (builtin.unwind_tables != .none or !builtin.strip_debug_info) asm volatile (
         \\ .cfi_undefined $ra
+    );
+    asm volatile (
         \\ move $fp, $zero
         \\ move $ra, $zero
         \\

lib/std/os/linux/powerpc.zig

@@ -1,3 +1,4 @@
+const builtin = @import("builtin");
 const std = @import("../../std.zig");
 const maxInt = std.math.maxInt;
 const linux = std.os.linux;
@@ -176,7 +177,11 @@ pub fn clone() callconv(.Naked) usize {
         \\
         \\ #else: we're the child
         \\ 2:
+    );
+    if (builtin.unwind_tables != .none or !builtin.strip_debug_info) asm volatile (
         \\ .cfi_undefined lr
+    );
+    asm volatile (
         \\ li 31, 0
         \\ mtlr 0
         \\

lib/std/os/linux/powerpc64.zig

@@ -1,3 +1,4 @@
+const builtin = @import("builtin");
 const std = @import("../../std.zig");
 const maxInt = std.math.maxInt;
 const linux = std.os.linux;
@@ -161,7 +162,11 @@ pub fn clone() callconv(.Naked) usize {
         \\  bnelr cr7
         \\
         \\  # we're the child
+    );
+    if (builtin.unwind_tables != .none or !builtin.strip_debug_info) asm volatile (
         \\  .cfi_undefined lr
+    );
+    asm volatile (
         \\  li    31, 0
         \\  mtlr   0
         \\

lib/std/os/linux/riscv32.zig

@@ -1,3 +1,4 @@
+const builtin = @import("builtin");
 const std = @import("../../std.zig");
 const iovec = std.posix.iovec;
 const iovec_const = std.posix.iovec_const;
@@ -120,7 +121,12 @@ pub fn clone() callconv(.Naked) usize {
         \\    ret
         \\
         \\    # Child
-        \\1:  .cfi_undefined ra
+        \\1:
+    );
+    if (builtin.unwind_tables != .none or !builtin.strip_debug_info) asm volatile (
+        \\    .cfi_undefined ra
+    );
+    asm volatile (
         \\    mv fp, zero
         \\    mv ra, zero
         \\

lib/std/os/linux/riscv64.zig

@@ -1,3 +1,4 @@
+const builtin = @import("builtin");
 const std = @import("../../std.zig");
 const iovec = std.posix.iovec;
 const iovec_const = std.posix.iovec_const;
@@ -120,7 +121,12 @@ pub fn clone() callconv(.Naked) usize {
         \\    ret
         \\
         \\    # Child
-        \\1:  .cfi_undefined ra
+        \\1:
+    );
+    if (builtin.unwind_tables != .none or !builtin.strip_debug_info) asm volatile (
+        \\    .cfi_undefined ra
+    );
+    asm volatile (
         \\    mv fp, zero
         \\    mv ra, zero
         \\

lib/std/os/linux/s390x.zig

@@ -1,3 +1,4 @@
+const builtin = @import("builtin");
 const std = @import("../../std.zig");
 const iovec = std.posix.iovec;
 const iovec_const = std.posix.iovec_const;
@@ -134,7 +135,11 @@ pub fn clone() callconv(.Naked) usize {
         \\bnzr %%r14
         \\
         \\# we're the child
+    );
+    if (builtin.unwind_tables != .none or !builtin.strip_debug_info) asm volatile (
         \\.cfi_undefined %%r14
+    );
+    asm volatile (
         \\lghi %%r11, 0
         \\lghi %%r14, 0
         \\

lib/std/os/linux/sparc64.zig

@@ -1,3 +1,4 @@
+const builtin = @import("builtin");
 const std = @import("../../std.zig");
 const maxInt = std.math.maxInt;
 const pid_t = linux.pid_t;
@@ -215,7 +216,11 @@ pub fn clone() callconv(.Naked) usize {
         \\ restore
         \\2:
         \\ # Child process
+    );
+    if (builtin.unwind_tables != .none or !builtin.strip_debug_info) asm volatile (
         \\ .cfi_undefined %%i7
+    );
+    asm volatile (
         \\ mov %%g0, %%fp
         \\ mov %%g0, %%i7
         \\

lib/std/os/linux/x86.zig

@@ -1,3 +1,4 @@
+const builtin = @import("builtin");
 const std = @import("../../std.zig");
 const maxInt = std.math.maxInt;
 const linux = std.os.linux;
@@ -156,7 +157,11 @@ pub fn clone() callconv(.Naked) usize {
         \\  retl
         \\
         \\1:
+    );
+    if (builtin.unwind_tables != .none or !builtin.strip_debug_info) asm volatile (
         \\  .cfi_undefined %%eip
+    );
+    asm volatile (
         \\  xorl %%ebp,%%ebp
         \\
         \\  popl %%eax

lib/std/os/linux/x86_64.zig

@@ -1,3 +1,4 @@
+const builtin = @import("builtin");
 const std = @import("../../std.zig");
 const maxInt = std.math.maxInt;
 const linux = std.os.linux;
@@ -117,7 +118,12 @@ pub fn clone() callconv(.Naked) usize {
         \\      jz 1f
         \\      retq
         \\
-        \\1:    .cfi_undefined %%rip
+        \\1:
+    );
+    if (builtin.unwind_tables != .none or !builtin.strip_debug_info) asm volatile (
+        \\      .cfi_undefined %%rip
+    );
+    asm volatile (
         \\      xorl %%ebp,%%ebp
         \\
         \\      popq %%rdi