From: Jens Remus Date: Tue, 9 Apr 2024 13:59:12 +0000 (+0200) Subject: s390: SFrame track FP/RA saved in register X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4e3cdaa9746d323edc54f87f7b9f3a219735ff6b;p=thirdparty%2Fbinutils-gdb.git s390: SFrame track FP/RA saved in register GCC on s390x, when in a leaf function, can be observed to save the frame pointer (FP) and/or return address (RA) register in a floating- point registers (FPR) instead of on the stack. This is declared using the following CFI directive: .cfi_register , SFrame cannot represent the FP and/or RA being saved in another register. It does only track the CFA base register (SP/FP), CFA offset from CFA base register, and FP and RA save area offsets from CFA. On s390x the FP and/or RA are only saved in another FPR when in a leaf function. That is a function that does not call any other functions. Therefore it can ever only be the topmost function in a call chain. During function return, if the RA would be restored into a non-default RA register, the function would also only ever be the topmost function on the call stack. An unwinder by default has access to all registers of the function that if the topmost on the call stack. Therefore no further information would be required for those registers. Represent the FP/RA in another register on s390, by encoding the register number shifted by one to the left with the least-significant bit set in the offset as follows: offset = (regno << 1) | 1 Add s390-specific SFrame (error) test cases for FP/RA being saved in FPRs in leaf-function. gas/ * gen-sframe.c (s390_sframe_xlate_do_register): New s390- specific function to represent FP/RA in another register on s390. (sframe_xlate_do_register): Invoke s390_sframe_xlate_do_register on s390. libsframe/ * sframe-dump.c (is_sframe_abi_arch_s390): New helper to test whether ABI/arch is s390. (dump_sframe_func_with_fres): Dump FP/RA in another register on s390. gas/testsuite/ * gas/cfi-sframe/cfi-sframe.exp: Update s390-specific SFrame (error) test cases. * gas/cfi-sframe/cfi-sframe-s390-fpra-register-err-2.s: Rename to ... * gas/cfi-sframe/cfi-sframe-s390-fpra-register-err-2.d: Likewise. * gas/cfi-sframe/cfi-sframe-s390-fpra-register-1.s: This. Test case no longer triggers a warning, as SFrame can represent FP and RA saved in registers. * gas/cfi-sframe/cfi-sframe-s390-fpra-register-1.d: Likewise. * gas/cfi-sframe/cfi-sframe-s390-fpra-register-err-1.d: Test case now triggers a different warning, as SFrame can represent FP and RA saved in registers, but not FP without RA saved in register. Signed-off-by: Jens Remus --- diff --git a/gas/gen-sframe.c b/gas/gen-sframe.c index dd97d4f8839..0bb7afb7e72 100644 --- a/gas/gen-sframe.c +++ b/gas/gen-sframe.c @@ -1152,6 +1152,37 @@ sframe_xlate_do_val_offset (struct sframe_xlate_ctx *xlate_ctx ATTRIBUTE_UNUSED, return SFRAME_XLATE_OK; } +/* S390-specific translate DW_CFA_register into SFrame context. + Return SFRAME_XLATE_OK if success. */ + +static int +s390_sframe_xlate_do_register (struct sframe_xlate_ctx *xlate_ctx, + struct cfi_insn_data *cfi_insn) +{ + /* The scratchpad FRE currently being updated with each cfi_insn + being interpreted. This FRE eventually gets linked in into the + list of FREs for the specific function. */ + struct sframe_row_entry *cur_fre = xlate_ctx->cur_fre; + + gas_assert (cur_fre); + + /* Change the rule for the register indicated by the register number to + be the specified register. Encode the register number as offset by + shifting it to the left by one and setting the least-significant bit + (LSB). The LSB can be used to differentiate offsets from register + numbers, as offsets from CFA are always a multiple of -8 on s390x. */ + if (cfi_insn->u.rr.reg1 == SFRAME_CFA_FP_REG) + sframe_fre_set_bp_track (cur_fre, cfi_insn->u.rr.reg2 << 1 | 1); +#ifdef SFRAME_FRE_RA_TRACKING + else if (sframe_ra_tracking_p () + && cfi_insn->u.rr.reg1 == SFRAME_CFA_RA_REG) + sframe_fre_set_ra_track (cur_fre, cfi_insn->u.rr.reg2 << 1 | 1); +#endif + + /* Safe to skip. */ + return SFRAME_XLATE_OK; +} + /* Translate DW_CFA_register into SFrame context. Return SFRAME_XLATE_OK if success. */ @@ -1159,6 +1190,10 @@ static int sframe_xlate_do_register (struct sframe_xlate_ctx *xlate_ctx ATTRIBUTE_UNUSED, struct cfi_insn_data *cfi_insn) { + /* Conditionally invoke S390-specific implementation. */ + if (sframe_get_abi_arch () == SFRAME_ABI_S390_ENDIAN_BIG) + return s390_sframe_xlate_do_register (xlate_ctx, cfi_insn); + /* Previous value of register1 is register2. However, if the specified register1 is not interesting (FP or RA reg), the current DW_CFA_register instruction can be safely skipped without sacrificing the asynchronicity of diff --git a/gas/testsuite/gas/cfi-sframe/cfi-sframe-s390-fpra-register-1.d b/gas/testsuite/gas/cfi-sframe/cfi-sframe-s390-fpra-register-1.d new file mode 100644 index 00000000000..736869834d8 --- /dev/null +++ b/gas/testsuite/gas/cfi-sframe/cfi-sframe-s390-fpra-register-1.d @@ -0,0 +1,22 @@ +#objdump: --sframe=.sframe +#name: SFrame generation on s390 - FP and RA registers saved in FPR registers +#... +Contents of the SFrame section .sframe: + + Header : + + Version: SFRAME_VERSION_2 + Flags: NONE + Num FDEs: 1 + Num FREs: 5 + + Function Index : + + func idx \[0\]: pc = 0x0, size = 26 bytes + STARTPC +CFA +FP +RA + + 0+0000 +sp\+160 +u +u + + 0+0004 +sp\+160 +u +r16 + + 0+0008 +sp\+160 +r17 +r16 + + 0+0014 +sp\+160 +u +r16 + + 0+0018 +sp\+160 +u +u + +#pass diff --git a/gas/testsuite/gas/cfi-sframe/cfi-sframe-s390-fpra-register-err-2.s b/gas/testsuite/gas/cfi-sframe/cfi-sframe-s390-fpra-register-1.s similarity index 100% rename from gas/testsuite/gas/cfi-sframe/cfi-sframe-s390-fpra-register-err-2.s rename to gas/testsuite/gas/cfi-sframe/cfi-sframe-s390-fpra-register-1.s diff --git a/gas/testsuite/gas/cfi-sframe/cfi-sframe-s390-fpra-register-err-1.d b/gas/testsuite/gas/cfi-sframe/cfi-sframe-s390-fpra-register-err-1.d index 2b9456be731..49d4e4a45af 100644 --- a/gas/testsuite/gas/cfi-sframe/cfi-sframe-s390-fpra-register-err-1.d +++ b/gas/testsuite/gas/cfi-sframe/cfi-sframe-s390-fpra-register-err-1.d @@ -1,6 +1,6 @@ -#name: SFrame generation on s390 - FP and RA saved in register +#name: SFrame generation on s390 - FP without RA saved in register #as: --gsframe -#warning: skipping SFrame FDE due to .cfi_register specifying FP register +#warning: skipping SFrame FDE due to FP without RA on stack #objdump: --sframe=.sframe #... Contents of the SFrame section .sframe: diff --git a/gas/testsuite/gas/cfi-sframe/cfi-sframe-s390-fpra-register-err-2.d b/gas/testsuite/gas/cfi-sframe/cfi-sframe-s390-fpra-register-err-2.d deleted file mode 100644 index 4c15bd0ae85..00000000000 --- a/gas/testsuite/gas/cfi-sframe/cfi-sframe-s390-fpra-register-err-2.d +++ /dev/null @@ -1,15 +0,0 @@ -#name: SFrame generation on s390 - FP and RA saved in register -#as: --gsframe -#warning: skipping SFrame FDE due to .cfi_register specifying RA register -#objdump: --sframe=.sframe -#... -Contents of the SFrame section .sframe: - - Header : - - Version: SFRAME_VERSION_2 - Flags: NONE - Num FDEs: 0 - Num FREs: 0 - -#pass diff --git a/gas/testsuite/gas/cfi-sframe/cfi-sframe.exp b/gas/testsuite/gas/cfi-sframe/cfi-sframe.exp index 67735d437c2..77281a189f2 100644 --- a/gas/testsuite/gas/cfi-sframe/cfi-sframe.exp +++ b/gas/testsuite/gas/cfi-sframe/cfi-sframe.exp @@ -110,6 +110,6 @@ if { [istarget "s390x*-*-*"] && [gas_sframe_check] } then { run_dump_test "cfi-sframe-s390-err-3" run_dump_test "cfi-sframe-s390-fpra-offset-1" run_dump_test "cfi-sframe-s390-fpra-offset-err-1" + run_dump_test "cfi-sframe-s390-fpra-register-1" run_dump_test "cfi-sframe-s390-fpra-register-err-1" - run_dump_test "cfi-sframe-s390-fpra-register-err-2" } diff --git a/libsframe/sframe-dump.c b/libsframe/sframe-dump.c index 69633d53a33..40ea531314b 100644 --- a/libsframe/sframe-dump.c +++ b/libsframe/sframe-dump.c @@ -40,6 +40,14 @@ is_sframe_abi_arch_aarch64 (sframe_decoder_ctx *sfd_ctx) return aarch64_p; } +/* Return TRUE if the SFrame section is associated with the s390 ABIs. */ + +static bool +is_sframe_abi_arch_s390 (sframe_decoder_ctx *sfd_ctx) +{ + return sframe_decoder_get_abi_arch (sfd_ctx) == SFRAME_ABI_S390_ENDIAN_BIG; +} + static void dump_sframe_header (sframe_decoder_ctx *sfd_ctx) { @@ -175,7 +183,12 @@ dump_sframe_func_with_fres (sframe_decoder_ctx *sfd_ctx, /* Dump SP/FP info. */ if (err[1] == 0) - sprintf (temp, "c%+d", fp_offset); + { + if (is_sframe_abi_arch_s390 (sfd_ctx) && (fp_offset & 1)) + sprintf (temp, "r%d", fp_offset >> 1); + else + sprintf (temp, "c%+d", fp_offset); + } else strcpy (temp, "u"); printf ("%-10s", temp); @@ -187,7 +200,12 @@ dump_sframe_func_with_fres (sframe_decoder_ctx *sfd_ctx, != SFRAME_CFA_FIXED_RA_INVALID) strcpy (temp, "f"); else if (err[2] == 0) - sprintf (temp, "c%+d", ra_offset); + { + if (is_sframe_abi_arch_s390 (sfd_ctx) && (ra_offset & 1)) + sprintf (temp, "r%d", ra_offset >> 1); + else + sprintf (temp, "c%+d", ra_offset); + } else strcpy (temp, "u");