* config/i386/morestack.S: Simplify CFI opcodes throughout.
From-SVN: r182609
This commit is contained in:
Ian Lance Taylor
parent
e2724fd212
commit
c9312a37c6
1 changed files with 29 additions and 42 deletions
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@ -100,14 +100,12 @@ __morestack_non_split:
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#ifndef __x86_64__
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# See below for an extended explanation of the CFI instructions.
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.cfi_offset 8, 8 # New PC stored at CFA + 8
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.cfi_escape 0x15, 4, 0x7d # DW_CFA_val_offset_sf, %esp, 12/-4
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# i.e., next %esp is CFA + 12
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# See below for an extended explanation of this.
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.cfi_def_cfa %esp,16
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pushl %eax # Save %eax in case it is a parameter.
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.cfi_def_cfa %esp,8 # Account for pushed register.
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.cfi_adjust_cfa_offset 4 # Account for pushed register.
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movl %esp,%eax # Current stack,
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subl 8(%esp),%eax # less required stack frame size,
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@ -144,16 +142,16 @@ __morestack_non_split:
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popl %eax # Restore %eax and stack.
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.cfi_def_cfa %esp,4 # Account for popped register.
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.cfi_adjust_cfa_offset -4 # Account for popped register.
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ret $8 # Return to caller, popping args.
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2:
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.cfi_def_cfa %esp,8 # Back to where we were.
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.cfi_adjust_cfa_offset 4 # Back to where we were.
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popl %eax # Restore %eax and stack.
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.cfi_def_cfa %esp,4 # Account for popped register.
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.cfi_adjust_cfa_offset -4 # Account for popped register.
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addl $0x5000+BACKOFF,4(%esp) # Increment space we request.
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@ -161,13 +159,12 @@ __morestack_non_split:
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#else
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# See below for an extended explanation of the CFI instructions.
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.cfi_offset 16, 0
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.cfi_escape 0x15, 7, 0x7f # DW_CFA_val_offset_sf, %esp, 8/-8
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# See below for an extended explanation of this.
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.cfi_def_cfa %rsp,16
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pushq %rax # Save %rax in case caller is using
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# it to preserve original %r10.
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.cfi_def_cfa %rsp,16 # Adjust for pushed register.
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.cfi_adjust_cfa_offset 8 # Adjust for pushed register.
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movq %rsp,%rax # Current stack,
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subq %r10,%rax # less required stack frame size,
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@ -178,27 +175,21 @@ __morestack_non_split:
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#else
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cmpl %fs:0x40,%eax
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#endif
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popq %rax # Restore register.
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.cfi_adjust_cfa_offset -8 # Adjust for popped register.
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jb 2f # Get more space if we need it.
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# This breaks call/return prediction, as described above.
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incq 8(%rsp) # Increment the return address.
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popq %rax # Restore register.
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.cfi_def_cfa %rsp,8 # Adjust for popped register.
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incq (%rsp) # Increment the return address.
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ret # Return to caller.
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2:
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.cfi_def_cfa %rsp,16 # Back to where we were.
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popq %rax # Restore register.
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.cfi_def_cfa %rsp,8 # Adjust for popped register.
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addq $0x5000+BACKOFF,%r10 # Increment space we request.
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# Fall throug into morestack.
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# Fall through into morestack.
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#endif
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@ -245,25 +236,22 @@ __morestack:
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# instruction, and just return to the real caller.
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# Here CFA points just past the return address on the stack,
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# e.g., on function entry it is %esp + 4. Later we will
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# change it to %ebp + 8, as set by .cfi_def_cfa_register and
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# .cfi_def_cfa_offset above. The stack looks like this:
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# e.g., on function entry it is %esp + 4. The stack looks
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# like this:
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# CFA + 12: stack pointer after two returns
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# CFA + 8: return address of morestack caller's caller
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# CFA + 4: size of parameters
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# CFA: new stack frame size
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# CFA - 4: return address of this function
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# CFA - 8: previous value of %ebp; %ebp points here
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# We want to set %esp to the stack pointer after the double
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# return, which is CFA + 12.
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.cfi_offset 8, 8 # New PC stored at CFA + 8
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.cfi_escape 0x15, 4, 0x7d # DW_CFA_val_offset_sf, %esp, 12/-4
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# i.e., next %esp is CFA + 12
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# Setting the new CFA to be the current CFA + 12 (i.e., %esp +
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# 16) will make the unwinder pick up the right return address.
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.cfi_def_cfa %esp,16
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# Set up a normal backtrace.
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pushl %ebp
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.cfi_def_cfa_offset 8
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.cfi_offset %ebp, -8
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.cfi_adjust_cfa_offset 4
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.cfi_offset %ebp, -20
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movl %esp,%ebp
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.cfi_def_cfa_register %ebp
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@ -281,7 +269,7 @@ __morestack:
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# register, since we don't change it, we just have to save it
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# for the unwinder.
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movl %ebx,-4(%ebp)
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.cfi_offset %ebx, -12
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.cfi_offset %ebx, -24
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# In 32-bit mode the registers %eax, %edx, and %ecx may be
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# used for parameters, depending on the regparm and fastcall
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@ -385,7 +373,7 @@ __morestack:
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popl %ebp
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.cfi_restore %ebp
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.cfi_def_cfa %esp, 4
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.cfi_def_cfa %esp, 16
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ret $8 # Return to caller, which will
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# immediately return. Pop
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# arguments as we go.
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@ -432,13 +420,12 @@ __morestack:
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# return to the caller of our caller. Let the unwinder skip
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# that single return instruction, and just return to the real
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# caller.
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.cfi_offset 16, 0
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.cfi_escape 0x15, 7, 0x7f # DW_CFA_val_offset_sf, %esp, 8/-8
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.cfi_def_cfa %rsp,16
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# Set up a normal backtrace.
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pushq %rbp
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.cfi_def_cfa_offset 16
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.cfi_offset %rbp, -16
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.cfi_adjust_cfa_offset 8
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.cfi_offset %rbp, -24
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movq %rsp, %rbp
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.cfi_def_cfa_register %rbp
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@ -551,7 +538,7 @@ __morestack:
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.cfi_remember_state
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popq %rbp
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.cfi_restore %rbp
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.cfi_def_cfa %rsp, 8
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.cfi_def_cfa %rsp, 16
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ret # Return to caller, which will
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# immediately return.
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