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@elikaski elikaski commented Dec 3, 2020

Compiling a simple Hello World program generates assembly code that contains:

	# (external call)
	movl (sp), %esp  # <REQ>
	movl $printf, (external)

When using post/xor.py (and other post scripts), the corresponding instructions generated are:

	# (external call)
	#xor> movl (sp), %esp  # <REQ>
	xorl %ebx, %ebx
	xorl (sp), %ebx
	xorl %esp  # <REQ>, %ebx
	xorl %ebx, %esp  # <REQ>

The third instruction is the problematic:
xorl %esp # <REQ>, %ebx

The root cause is that the comment (# <REQ>) is also being identified as the "destination" register
My change makes it discard the comment

Compiling a simple Hello World program generates assembly code that contains:

	# (external call)
	movl (sp), %esp  # <REQ>
	movl $printf, (external)

When using post/xor.py (and other post scripts), the corresponding instructions generated are:

	# (external call)
	#xor> movl (sp), %esp  # <REQ>
	xorl %ebx, %ebx
	xorl (sp), %ebx
	xorl %esp  # <REQ>, %ebx
	xorl %ebx, %esp  # <REQ>

The third instruction is the problematic:
	xorl %esp  # <REQ>, %ebx

The root cause is that the comment (# <REQ>) is also being identified as the "destination" register
My change makes it discard the comment
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