Msg/ClobberedSP: Difference between revisions
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< Msg
					
					< Msg
| Line 21: | Line 21: | ||
| .global _start | .global _start | ||
| _start: | _start: | ||
|     movi sp, 0x1000		# Initialize SP | |||
|     call Function | |||
|      nop |      nop | ||
|      nop |      nop | ||
| Function: | Function: | ||
|     subi sp, sp, 4		# Modify SP | |||
|      ret					# SP is different at return |      ret					# SP is different at return | ||
| </syntaxhighlight> | </syntaxhighlight> | ||
| {{DisableMsg|Function clobbered ra or sp}} | {{DisableMsg|Function clobbered ra or sp}} | ||
Revision as of 23:25, 9 March 2019
A function should always ensure that the stack pointer is the same at the entry and exit of the function. This message tells you that this didn't happen: the stack pointer was different at the function return than when the function was first called.
Examples
ARMv7
.global _start
_start:
    mov sp, #0x1000		// Initialize SP to something sane
    bl MyFunction
    nop
    nop
    # ...
    
MyFunction:
    push {r4}	// Change SP
    bx lr		// SP is different at return
Nios II
.global _start
_start:
    movi sp, 0x1000		# Initialize SP
    call Function
    nop
    nop
    
Function:
    subi sp, sp, 4		# Modify SP
    ret					# SP is different at return
Disabling this message
This debugging check can be disabled in the Debugging Checks section of the Settings box: Function clobbered ra or sp.