| GNU Compiler Collection (GCC) Internals: Profiling |
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These macros will help you generate code for profiling.
A C statement or compound statement to output to file some
assembler code to call the profiling subroutine mcount.
The details of how mcount expects to be called are determined by
your operating system environment, not by GCC. To figure them out,
compile a small program for profiling using the system’s installed C
compiler and look at the assembler code that results.
Older implementations of mcount expect the address of a counter
variable to be loaded into some register. The name of this variable is
‘LP’ followed by the number labelno, so you would generate
the name using ‘LP%d’ in a fprintf.
A C statement or compound statement to output to file some assembly
code to call the profiling subroutine mcount even the target does
not support profiling.
Define this macro to be an expression with a nonzero value if the
mcount subroutine on your system does not need a counter variable
allocated for each function. This is true for almost all modern
implementations. If you define this macro, you must not use the
labelno argument to FUNCTION_PROFILER.
Define this macro if the code for function profiling should come before the function prologue. Normally, the profiling code comes after.
This target hook returns true if the target wants the leaf flag for the current function to stay true even if it calls mcount. This might make sense for targets using the leaf flag only to determine whether a stack frame needs to be generated or not and for which the call to mcount is generated before the function prologue.
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