diff options
| -rw-r--r-- | gcc/ChangeLog | 14 | ||||
| -rw-r--r-- | gcc/config/aarch64/aarch64-protos.h | 2 | ||||
| -rw-r--r-- | gcc/config/aarch64/aarch64.c | 77 | ||||
| -rw-r--r-- | gcc/config/aarch64/aarch64.h | 6 | ||||
| -rw-r--r-- | gcc/config/aarch64/aarch64.md | 19 | ||||
| -rw-r--r-- | gcc/testsuite/ChangeLog | 4 | ||||
| -rw-r--r-- | gcc/testsuite/gcc.target/aarch64/eh_return.c | 82 |
7 files changed, 139 insertions, 65 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 049fdb0..a8ba01c 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,17 @@ +2017-01-17 Wilco Dijkstra <wdijkstr@arm.com> + + * config/aarch64/aarch64.md (eh_return): Remove pattern and splitter. + * config/aarch64/aarch64.h (AARCH64_EH_STACKADJ_REGNUM): Remove. + (EH_RETURN_HANDLER_RTX): New define. + * config/aarch64/aarch64.c (aarch64_frame_pointer_required): + Force frame pointer in EH return functions. + (aarch64_expand_epilogue): Add barrier for eh_return. + (aarch64_final_eh_return_addr): Remove. + (aarch64_eh_return_handler_rtx): New function. + * config/aarch64/aarch64-protos.h (aarch64_final_eh_return_addr): + Remove. + (aarch64_eh_return_handler_rtx): New prototype. + 2017-01-17 Bill Schmidt <wschmidt@linux.vnet.ibm.com> * config/rs6000/altivec.h (vec_rlmi): New #define. diff --git a/gcc/config/aarch64/aarch64-protos.h b/gcc/config/aarch64/aarch64-protos.h index 29a3bd7..602f54f 100644 --- a/gcc/config/aarch64/aarch64-protos.h +++ b/gcc/config/aarch64/aarch64-protos.h @@ -358,7 +358,7 @@ int aarch64_hard_regno_mode_ok (unsigned, machine_mode); int aarch64_hard_regno_nregs (unsigned, machine_mode); int aarch64_uxt_size (int, HOST_WIDE_INT); int aarch64_vec_fpconst_pow_of_2 (rtx); -rtx aarch64_final_eh_return_addr (void); +rtx aarch64_eh_return_handler_rtx (void); rtx aarch64_mask_from_zextract_ops (rtx, rtx); const char *aarch64_output_move_struct (rtx *operands); rtx aarch64_return_addr (int, rtx); diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c index 67500c8..27f2dc9 100644 --- a/gcc/config/aarch64/aarch64.c +++ b/gcc/config/aarch64/aarch64.c @@ -2762,6 +2762,10 @@ aarch64_frame_pointer_required (void) && (!crtl->is_leaf || df_regs_ever_live_p (LR_REGNUM))) return true; + /* Force a frame pointer for EH returns so the return address is at FP+8. */ + if (crtl->calls_eh_return) + return true; + return false; } @@ -3620,7 +3624,8 @@ aarch64_expand_epilogue (bool for_sibcall) + cfun->machine->frame.saved_varargs_size) != 0; /* Emit a barrier to prevent loads from a deallocated stack. */ - if (final_adjust > crtl->outgoing_args_size || cfun->calls_alloca) + if (final_adjust > crtl->outgoing_args_size || cfun->calls_alloca + || crtl->calls_eh_return) { emit_insn (gen_stack_tie (stack_pointer_rtx, stack_pointer_rtx)); need_barrier_p = false; @@ -3688,52 +3693,40 @@ aarch64_expand_epilogue (bool for_sibcall) emit_jump_insn (ret_rtx); } -/* Return the place to copy the exception unwinding return address to. - This will probably be a stack slot, but could (in theory be the - return register). */ -rtx -aarch64_final_eh_return_addr (void) -{ - HOST_WIDE_INT fp_offset; - - aarch64_layout_frame (); +/* Implement EH_RETURN_HANDLER_RTX. EH returns need to either return + normally or return to a previous frame after unwinding. - fp_offset = cfun->machine->frame.frame_size - - cfun->machine->frame.hard_fp_offset; + An EH return uses a single shared return sequence. The epilogue is + exactly like a normal epilogue except that it has an extra input + register (EH_RETURN_STACKADJ_RTX) which contains the stack adjustment + that must be applied after the frame has been destroyed. An extra label + is inserted before the epilogue which initializes this register to zero, + and this is the entry point for a normal return. - if (cfun->machine->frame.reg_offset[LR_REGNUM] < 0) - return gen_rtx_REG (DImode, LR_REGNUM); + An actual EH return updates the return address, initializes the stack + adjustment and jumps directly into the epilogue (bypassing the zeroing + of the adjustment). Since the return address is typically saved on the + stack when a function makes a call, the saved LR must be updated outside + the epilogue. - /* DSE and CSELIB do not detect an alias between sp+k1 and fp+k2. This can - result in a store to save LR introduced by builtin_eh_return () being - incorrectly deleted because the alias is not detected. - So in the calculation of the address to copy the exception unwinding - return address to, we note 2 cases. - If FP is needed and the fp_offset is 0, it means that SP = FP and hence - we return a SP-relative location since all the addresses are SP-relative - in this case. This prevents the store from being optimized away. - If the fp_offset is not 0, then the addresses will be FP-relative and - therefore we return a FP-relative location. */ + This poses problems as the store is generated well before the epilogue, + so the offset of LR is not known yet. Also optimizations will remove the + store as it appears dead, even after the epilogue is generated (as the + base or offset for loading LR is different in many cases). - if (frame_pointer_needed) - { - if (fp_offset) - return gen_frame_mem (DImode, - plus_constant (Pmode, hard_frame_pointer_rtx, UNITS_PER_WORD)); - else - return gen_frame_mem (DImode, - plus_constant (Pmode, stack_pointer_rtx, UNITS_PER_WORD)); - } - - /* If FP is not needed, we calculate the location of LR, which would be - at the top of the saved registers block. */ + To avoid these problems this implementation forces the frame pointer + in eh_return functions so that the location of LR is fixed and known early. + It also marks the store volatile, so no optimization is permitted to + remove the store. */ +rtx +aarch64_eh_return_handler_rtx (void) +{ + rtx tmp = gen_frame_mem (Pmode, + plus_constant (Pmode, hard_frame_pointer_rtx, UNITS_PER_WORD)); - return gen_frame_mem (DImode, - plus_constant (Pmode, - stack_pointer_rtx, - fp_offset - + cfun->machine->frame.saved_regs_size - - 2 * UNITS_PER_WORD)); + /* Mark the store volatile, so no optimization is permitted to remove it. */ + MEM_VOLATILE_P (tmp) = true; + return tmp; } /* Output code to add DELTA to the first argument, and then jump diff --git a/gcc/config/aarch64/aarch64.h b/gcc/config/aarch64/aarch64.h index 7b0df99..f6c18e8 100644 --- a/gcc/config/aarch64/aarch64.h +++ b/gcc/config/aarch64/aarch64.h @@ -400,9 +400,9 @@ extern unsigned aarch64_architecture_version; #define ASM_DECLARE_FUNCTION_NAME(STR, NAME, DECL) \ aarch64_declare_function_name (STR, NAME, DECL) -/* The register that holds the return address in exception handlers. */ -#define AARCH64_EH_STACKADJ_REGNUM (R0_REGNUM + 4) -#define EH_RETURN_STACKADJ_RTX gen_rtx_REG (Pmode, AARCH64_EH_STACKADJ_REGNUM) +/* For EH returns X4 contains the stack adjustment. */ +#define EH_RETURN_STACKADJ_RTX gen_rtx_REG (Pmode, R4_REGNUM) +#define EH_RETURN_HANDLER_RTX aarch64_eh_return_handler_rtx () /* Don't use __builtin_setjmp until we've defined it. */ #undef DONT_USE_BUILTIN_SETJMP diff --git a/gcc/config/aarch64/aarch64.md b/gcc/config/aarch64/aarch64.md index bde4231..b3be106 100644 --- a/gcc/config/aarch64/aarch64.md +++ b/gcc/config/aarch64/aarch64.md @@ -592,25 +592,6 @@ [(set_attr "type" "branch")] ) -(define_insn "eh_return" - [(unspec_volatile [(match_operand:DI 0 "register_operand" "r")] - UNSPECV_EH_RETURN)] - "" - "#" - [(set_attr "type" "branch")] - -) - -(define_split - [(unspec_volatile [(match_operand:DI 0 "register_operand" "")] - UNSPECV_EH_RETURN)] - "reload_completed" - [(set (match_dup 1) (match_dup 0))] - { - operands[1] = aarch64_final_eh_return_addr (); - } -) - (define_insn "*cb<optab><mode>1" [(set (pc) (if_then_else (EQL (match_operand:GPI 0 "register_operand" "r") (const_int 0)) diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 7cdf31c..eb1e3cc 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,7 @@ +2017-01-17 Wilco Dijkstra <wdijkstr@arm.com> + + * gcc.target/aarch64/eh_return.c: New test. + 2017-01-17 Bill Schmidt <wschmidt@linux.vnet.ibm.com> * vec-rlmi-rlnm.c: New file. diff --git a/gcc/testsuite/gcc.target/aarch64/eh_return.c b/gcc/testsuite/gcc.target/aarch64/eh_return.c new file mode 100644 index 0000000..3217948 --- /dev/null +++ b/gcc/testsuite/gcc.target/aarch64/eh_return.c @@ -0,0 +1,82 @@ +/* { dg-do run } */ +/* { dg-options "-O2 -fno-inline" } */ + +#include <stdlib.h> +#include <stdio.h> + +int val, test, failed; + +int main (void); + +void +eh0 (void *p) +{ + val = (int)(long)p & 7; + if (val) + abort (); +} + +void +eh1 (void *p, int x) +{ + void *q = __builtin_alloca (x); + eh0 (q); + __builtin_eh_return (0, p); +} + +void +eh2a (int a,int b,int c,int d,int e,int f,int g,int h, void *p) +{ + val = a + b + c + d + e + f + g + h + (int)(long)p & 7; +} + +void +eh2 (void *p) +{ + eh2a (val, val, val, val, val, val, val, val, p); + __builtin_eh_return (0, p); +} + + +void +continuation (void) +{ + test++; + main (); +} + +void +fail (void) +{ + failed = 1; + printf ("failed\n"); + continuation (); +} + +void +do_test1 (void) +{ + if (!val) + eh1 (continuation, 100); + fail (); +} + +void +do_test2 (void) +{ + if (!val) + eh2 (continuation); + fail (); +} + +int +main (void) +{ + if (test == 0) + do_test1 (); + if (test == 1) + do_test2 (); + if (failed || test != 2) + exit (1); + exit (0); +} |