On 18/06/14 15:16, Yufeng Zhang wrote:
> Hi,
>
> This improves the robustness of the aapcs64 test framework for testing
> function return ABI rules. It ensures the test facility functions now
> able to see the exact content of return registers right at the moment
> when a function returns.
>
> OK for trunk?
OK once the issues with the comment are clarified.
R.
>
> Thanks,
> Yufeng
>
> gcc/testsuite
>
> Make the AAPCS64 function return tests more robust.
>
> * gcc.target/aarch64/aapcs64/abitest-2.h (saved_return_address): New
> global variable.
> (FUNC_VAL_CHECK): Update to call myfunc via the 'ret' instruction,
> instead of calling sequentially in the C code.
> * gcc.target/aarch64/aapcs64/abitest.S (LABEL_TEST_FUNC_RETURN): Store
> saved_return_address to the stack frame where LR register was stored.
> (saved_return_address): Declare weak.
>
>
> patch
>
>
> diff --git a/gcc/testsuite/gcc.target/aarch64/aapcs64/abitest-2.h
> b/gcc/testsuite/gcc.target/aarch64/aapcs64/abitest-2.h
> index c56e7cc..c87fe9b 100644
> --- a/gcc/testsuite/gcc.target/aarch64/aapcs64/abitest-2.h
> +++ b/gcc/testsuite/gcc.target/aarch64/aapcs64/abitest-2.h
> @@ -5,6 +5,7 @@
> #include "validate_memory.h"
>
> void (*testfunc_ptr)(char* stack);
> +unsigned long long saved_return_address;
>
> /* Helper macros to generate function name. Example of the function name:
> func_return_val_1. */
> @@ -71,6 +72,17 @@ __attribute__ ((noinline)) type FUNC_NAME (id) (int i,
> double d, type t) \
> optimized away. Using i and d prevents \
> warnings about unused parameters. \
> */ \
> + /* We save and set up the LR register in a way that essentially \
> + inserts myfunc () between the returning of this function and the
> \
s/returning/return/
> + continueous execution of its caller. By doing this, myfunc ()
> \
Typo: continueous. Do you mean continuing?
> + can save and check the exact content of the registers that are
> \
> + used for the function return value.
> \
stray tab.
> + The previous approach of sequentially calling myfunc right after
> \
> + this function does not guarantee myfunc see the exact register
> \
> + content, as compiler may emit code in between the two calls,
> \
Similarly.
> + especially during the -O0 codegen. */
> \
> + asm volatile ("mov %0, x30" : "=r" (saved_return_address));
> \
> + asm volatile ("mov x30, %0" : : "r" ((unsigned long long) myfunc)); \
> return t;
> \
> }
> #include TESTFILE
> @@ -84,7 +96,8 @@ __attribute__ ((noinline)) type FUNC_NAME (id) (int i,
> double d, type t) \
> { \
> testfunc_ptr = TEST_FUNC_NAME(id);
> \
> FUNC_NAME(id) (0, 0.0, var); \
> - myfunc ();
> \
> + /* The above function implicitly calls myfunc () on its return, \
> + and the execution resumes from here after myfunc () finishes. */\
> }
>
> int main()
> diff --git a/gcc/testsuite/gcc.target/aarch64/aapcs64/abitest.S
> b/gcc/testsuite/gcc.target/aarch64/aapcs64/abitest.S
> index 86ce7be..68845fb 100644
> --- a/gcc/testsuite/gcc.target/aarch64/aapcs64/abitest.S
> +++ b/gcc/testsuite/gcc.target/aarch64/aapcs64/abitest.S
> @@ -50,6 +50,10 @@ LABEL_TEST_FUNC_RETURN:
> add x9, x9, :lo12:testfunc_ptr
> ldr x9, [x9, #0]
> blr x9 // function return value test
> + adrp x9, saved_return_address
> + add x9, x9, :lo12:saved_return_address
> + ldr x9, [x9, #0]
> + str x9, [sp, #8] // Update the copy of LR reg
> saved on stack
> LABEL_RET:
> ldp x0, x30, [sp]
> mov sp, x0
> @@ -57,3 +61,4 @@ LABEL_RET:
>
> .weak testfunc
> .weak testfunc_ptr
> +.weak saved_return_address
>
