Please also explain the need for backpointer section.
David http://codereview.appspot.com/5416043/diff/1/gcc/config/i386/i386.c File gcc/config/i386/i386.c (right): http://codereview.appspot.com/5416043/diff/1/gcc/config/i386/i386.c#newcode10801 gcc/config/i386/i386.c:10801: +static bool Add an empty line between comment and function. http://codereview.appspot.com/5416043/diff/1/gcc/config/i386/i386.c#newcode10811 gcc/config/i386/i386.c:10811: + if (!patch_functions_ignore_loops) What exactly does this option try to do here? http://codereview.appspot.com/5416043/diff/1/gcc/config/i386/i386.c#newcode10822 gcc/config/i386/i386.c:10822: + return true; should it have a an else return false here? http://codereview.appspot.com/5416043/diff/1/gcc/config/i386/i386.c#newcode10841 gcc/config/i386/i386.c:10841: + ++num_insns; NON_DEBUG_INSN_P (insn) http://codereview.appspot.com/5416043/diff/1/gcc/config/i386/i386.c#newcode10859 gcc/config/i386/i386.c:10859: + patch_current_function_p = check_should_patch_current_function(); Why do you need a static variable for this? http://codereview.appspot.com/5416043/diff/1/gcc/config/i386/i386.c#newcode10874 gcc/config/i386/i386.c:10874: + '_function_patch_epilogue'. Explain why a backpointer section is needed. http://codereview.appspot.com/5416043/diff/1/gcc/config/i386/i386.c#newcode10888 gcc/config/i386/i386.c:10888: + unsigned int num_actual_nops = num_remaining_nops - 8; hard code of 8? http://codereview.appspot.com/5416043/diff/1/gcc/config/i386/i386.c#newcode10897 gcc/config/i386/i386.c:10897: + return false; Can this be guarded in the caller of this function? http://codereview.appspot.com/5416043/diff/1/gcc/config/i386/i386.c#newcode10927 gcc/config/i386/i386.c:10927: + is later renamed to '<section_name>' by ix86_elf_asm_named_section(). */ Explain more on the comdat handling. http://codereview.appspot.com/5416043/diff/1/gcc/config/i386/i386.opt File gcc/config/i386/i386.opt (right): http://codereview.appspot.com/5416043/diff/1/gcc/config/i386/i386.opt#newcode570 gcc/config/i386/i386.opt:570: Minimum number of instructions in the function without loop before the function is qualified for patching for instrumentation (for use with -mpatch-functions-for-instrumentation) It may be better to define PARAM for it. http://codereview.appspot.com/5416043/diff/1/gcc/config/i386/i386.opt#newcode574 gcc/config/i386/i386.opt:574: Ignore loops when deciding whether to patch a function for instrumentation (for use with -mpatch-functions-for-instrumentation). What is the motivation for this option? http://codereview.appspot.com/5416043/diff/1/gcc/config/i386/i386.opt#newcode578 gcc/config/i386/i386.opt:578: Treat 'main' as any other function and only patch it if it meets the criteria for loops and minimum number of instructions (for use with -mpatch-functions-for-instrumentation). What is the motivation for this option? http://codereview.appspot.com/5416043/
