* config/i386/morestack.S: Simplify CFI opcodes throughout.

From-SVN: r182609

diff --git a/libgcc/config/i386/morestack.S b/libgcc/config/i386/morestack.S
index 8e0eb20..62f7ce1 100644 (file)
--- a/libgcc/config/i386/morestack.S
+++ b/libgcc/config/i386/morestack.S
@@ -100,14 +100,12 @@ __morestack_non_split:
 
 #ifndef __x86_64__
 
-       # See below for an extended explanation of the CFI instructions.
-       .cfi_offset 8, 8                # New PC stored at CFA + 8
-       .cfi_escape 0x15, 4, 0x7d       # DW_CFA_val_offset_sf, %esp, 12/-4
-                                       # i.e., next %esp is CFA + 12
+       # See below for an extended explanation of this.
+       .cfi_def_cfa %esp,16
 
        pushl   %eax                    # Save %eax in case it is a parameter.
 
-       .cfi_def_cfa %esp,8             # Account for pushed register.
+       .cfi_adjust_cfa_offset 4        # Account for pushed register.
 
        movl    %esp,%eax               # Current stack,
        subl    8(%esp),%eax            # less required stack frame size,
@@ -144,16 +142,16 @@ __morestack_non_split:
 
        popl    %eax                    # Restore %eax and stack.
 
-       .cfi_def_cfa %esp,4             # Account for popped register.
+       .cfi_adjust_cfa_offset -4       # Account for popped register.
 
        ret     $8                      # Return to caller, popping args.
 
 2:
-       .cfi_def_cfa %esp,8             # Back to where we were.
+       .cfi_adjust_cfa_offset 4        # Back to where we were.
 
        popl    %eax                    # Restore %eax and stack.
 
-       .cfi_def_cfa %esp,4             # Account for popped register.
+       .cfi_adjust_cfa_offset -4       # Account for popped register.
 
        addl    $0x5000+BACKOFF,4(%esp) # Increment space we request.
 
@@ -161,13 +159,12 @@ __morestack_non_split:
 
 #else
 
-       # See below for an extended explanation of the CFI instructions.
-       .cfi_offset 16, 0
-       .cfi_escape 0x15, 7, 0x7f       # DW_CFA_val_offset_sf, %esp, 8/-8
+       # See below for an extended explanation of this.
+       .cfi_def_cfa %rsp,16
 
        pushq   %rax                    # Save %rax in case caller is using
                                        # it to preserve original %r10.
-       .cfi_def_cfa %rsp,16            # Adjust for pushed register.
+       .cfi_adjust_cfa_offset 8        # Adjust for pushed register.
 
        movq    %rsp,%rax               # Current stack,
        subq    %r10,%rax               # less required stack frame size,
@@ -178,27 +175,21 @@ __morestack_non_split:
 #else
        cmpl    %fs:0x40,%eax
 #endif
-       jb      2f                      # Get more space if we need it.
+       popq    %rax                    # Restore register.
 
-       # This breaks call/return prediction, as described above.
-       incq    8(%rsp)                 # Increment the return address.
+       .cfi_adjust_cfa_offset -8       # Adjust for popped register.
 
-       popq    %rax                    # Restore register.
+       jb      2f                      # Get more space if we need it.
 
-       .cfi_def_cfa %rsp,8             # Adjust for popped register.
+       # This breaks call/return prediction, as described above.
+       incq    (%rsp)                  # Increment the return address.
 
        ret                             # Return to caller.
 
 2:
-       .cfi_def_cfa %rsp,16            # Back to where we were.
-
-       popq    %rax                    # Restore register.
-
-       .cfi_def_cfa %rsp,8             # Adjust for popped register.
-
        addq    $0x5000+BACKOFF,%r10    # Increment space we request.
 
-       # Fall throug into morestack.
+       # Fall through into morestack.
 
 #endif
 
@@ -245,25 +236,22 @@ __morestack:
        # instruction, and just return to the real caller.
 
        # Here CFA points just past the return address on the stack,
-       # e.g., on function entry it is %esp + 4.  Later we will
-       # change it to %ebp + 8, as set by .cfi_def_cfa_register and
-       # .cfi_def_cfa_offset above.  The stack looks like this:
+       # e.g., on function entry it is %esp + 4.  The stack looks
+       # like this:
        #       CFA + 12:       stack pointer after two returns
        #       CFA + 8:        return address of morestack caller's caller
        #       CFA + 4:        size of parameters
        #       CFA:            new stack frame size
        #       CFA - 4:        return address of this function
        #       CFA - 8:        previous value of %ebp; %ebp points here
-       # We want to set %esp to the stack pointer after the double
-       # return, which is CFA + 12.
-       .cfi_offset 8, 8                # New PC stored at CFA + 8
-       .cfi_escape 0x15, 4, 0x7d       # DW_CFA_val_offset_sf, %esp, 12/-4
-                                       # i.e., next %esp is CFA + 12
+       # Setting the new CFA to be the current CFA + 12 (i.e., %esp +
+       # 16) will make the unwinder pick up the right return address.
+
+       .cfi_def_cfa %esp,16
 
-       # Set up a normal backtrace.
        pushl   %ebp
-       .cfi_def_cfa_offset 8
-       .cfi_offset %ebp, -8
+       .cfi_adjust_cfa_offset 4
+       .cfi_offset %ebp, -20
        movl    %esp,%ebp
        .cfi_def_cfa_register %ebp
 
@@ -281,7 +269,7 @@ __morestack:
        # register, since we don't change it, we just have to save it
        # for the unwinder.
        movl    %ebx,-4(%ebp)
-       .cfi_offset %ebx, -12
+       .cfi_offset %ebx, -24
 
        # In 32-bit mode the registers %eax, %edx, and %ecx may be
        # used for parameters, depending on the regparm and fastcall
@@ -385,7 +373,7 @@ __morestack:
 
        popl    %ebp
        .cfi_restore %ebp
-       .cfi_def_cfa %esp, 4
+       .cfi_def_cfa %esp, 16
        ret     $8                      # Return to caller, which will
                                        # immediately return.  Pop
                                        # arguments as we go.
@@ -432,13 +420,12 @@ __morestack:
        # return to the caller of our caller.  Let the unwinder skip
        # that single return instruction, and just return to the real
        # caller.
-       .cfi_offset 16, 0
-       .cfi_escape 0x15, 7, 0x7f       # DW_CFA_val_offset_sf, %esp, 8/-8
+       .cfi_def_cfa %rsp,16
 
        # Set up a normal backtrace.
        pushq   %rbp
-       .cfi_def_cfa_offset 16
-       .cfi_offset %rbp, -16
+       .cfi_adjust_cfa_offset 8
+       .cfi_offset %rbp, -24
        movq    %rsp, %rbp
        .cfi_def_cfa_register %rbp
 
@@ -551,7 +538,7 @@ __morestack:
        .cfi_remember_state
        popq    %rbp
        .cfi_restore %rbp
-       .cfi_def_cfa %rsp, 8
+       .cfi_def_cfa %rsp, 16
        ret                             # Return to caller, which will
                                        # immediately return.