From b2a02961b4407ca76db5a66ca5ae855cbfba4e8e Mon Sep 17 00:00:00 2001 From: Kirill Smelkov Date: Thu, 15 Nov 2012 03:31:49 +0400 Subject: Add support for __builtin_frame_address(level) Continuing d6072d37 (Add __builtin_frame_address(0)) implement __builtin_frame_address for levels greater than zero, in order for tinycc to be able to compile its own lib/bcheck.c after cffb7af9 (lib/bcheck: Prevent __bound_local_new / __bound_local_delete from being miscompiled). I'm new to the internals, and used the most simple way to do it. Generated code is not very good for levels >= 2, compare gcc tcc level=0 mov %ebp,%eax lea 0x0(%ebp),%eax level=1 mov 0x0(%ebp),%eax mov 0x0(%ebp),%eax level=2 mov 0x0(%ebp),%eax mov 0x0(%ebp),%eax mov (%eax),%eax mov %eax,-0x10(%ebp) mov -0x10(%ebp),%eax mov (%eax),%eax level=3 mov 0x0(%ebp),%eax mov 0x0(%ebp),%eax mov (%eax),%eax mov (%eax),%ecx mov (%eax),%eax mov (%ecx),%eax But this is still an improvement and for bcheck we need level=1 for which the code is good. For the tests I had to force gcc use -O0 to not inline the functions. And -fno-omit-frame-pointer just in case. If someone knows how to improve the generated code - help is appreciated. Thanks, Kirill Cc: Michael Matz Cc: Shinichiro Hamaji --- tests/tcctest.c | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) (limited to 'tests/tcctest.c') diff --git a/tests/tcctest.c b/tests/tcctest.c index 82762ea..4f9f2a3 100644 --- a/tests/tcctest.c +++ b/tests/tcctest.c @@ -89,6 +89,7 @@ void global_data_test(void); void cmp_comparison_test(void); void math_cmp_test(void); void callsave_test(void); +void builtin_frame_address_test(void); int fib(int n); void num(int n); @@ -598,6 +599,7 @@ int main(int argc, char **argv) cmp_comparison_test(); math_cmp_test(); callsave_test(); + builtin_frame_address_test(); return 0; } @@ -2680,3 +2682,28 @@ void callsave_test(void) printf ("%d\n", i); #endif } + + +void bfa3(ptrdiff_t str_offset) +{ + printf("bfa3: %s\n", (char *)__builtin_frame_address(3) + str_offset); +} +void bfa2(ptrdiff_t str_offset) +{ + printf("bfa2: %s\n", (char *)__builtin_frame_address(2) + str_offset); + bfa3(str_offset); +} +void bfa1(ptrdiff_t str_offset) +{ + printf("bfa1: %s\n", (char *)__builtin_frame_address(1) + str_offset); + bfa2(str_offset); +} + +void builtin_frame_address_test(void) +{ + char str[] = "__builtin_frame_address"; + char *fp0 = __builtin_frame_address(0); + + printf("str: %s\n", str); + bfa1(str-fp0); +} -- cgit v1.3.1