From 5266d753623782fb1397cdd258b5ea5373bd91ab Mon Sep 17 00:00:00 2001 From: Di Chen Date: Thu, 28 Jul 2022 16:31:05 +0800 Subject: [PATCH] libdwfl: Add new function dwfl_frame_reg Dwfl has most of the infrastructure to keep the full unwind state, including the state of unwound registers per frame using Dwfl_Thread_Callbacks. But there is no public API to access the state, except for the PC (dwfl_frame_pc). This commit adds a new function dwfl_frame_reg to get the value of the DWARF register number in the given frame. https://sourceware.org/bugzilla/show_bug.cgi?id=28579 Signed-off-by: Di Chen --- NEWS | 2 ++ libdw/libdw.map | 1 + libdwfl/dwfl_frame_regs.c | 12 +++++++++++ libdwfl/frame_unwind.c | 40 ++++++++++++++----------------------- libdwfl/libdwfl.h | 6 ++++++ libdwfl/libdwflP.h | 10 +++++++--- libdwfl/linux-core-attach.c | 2 +- 7 files changed, 44 insertions(+), 29 deletions(-) diff --git a/NEWS b/NEWS index 392f2edc..eb1a2c6b 100644 --- a/NEWS +++ b/NEWS @@ -4,6 +4,8 @@ debuginfod: Add --disable-source-scan option. libdwfl: Add new function dwfl_get_debuginfod_client. +libdwfl: Add new function dwfl_frame_reg. + Version 0.187 debuginfod: Support -C option for connection thread pooling. diff --git a/libdw/libdw.map b/libdw/libdw.map index 6da25561..8f393438 100644 --- a/libdw/libdw.map +++ b/libdw/libdw.map @@ -370,4 +370,5 @@ ELFUTILS_0.186 { ELFUTILS_0.188 { global: dwfl_get_debuginfod_client; + dwfl_frame_reg; } ELFUTILS_0.186; diff --git a/libdwfl/dwfl_frame_regs.c b/libdwfl/dwfl_frame_regs.c index 83b1abef..a4bd3884 100644 --- a/libdwfl/dwfl_frame_regs.c +++ b/libdwfl/dwfl_frame_regs.c @@ -59,3 +59,15 @@ dwfl_thread_state_register_pc (Dwfl_Thread *thread, Dwarf_Word pc) state->pc_state = DWFL_FRAME_STATE_PC_SET; } INTDEF(dwfl_thread_state_register_pc) + +int +dwfl_frame_reg (Dwfl_Frame *state, unsigned regno, Dwarf_Word *val) +{ + int res = __libdwfl_frame_reg_get (state, regno, val); + if (res == -1) + __libdwfl_seterrno (DWFL_E_INVALID_REGISTER); + else if (res == 1) + __libdwfl_seterrno (DWFL_E_REGISTER_VAL_UNKNOWN); + return res; +} +INTDEF(dwfl_frame_reg) diff --git a/libdwfl/frame_unwind.c b/libdwfl/frame_unwind.c index 9ac33833..8185d84b 100644 --- a/libdwfl/frame_unwind.c +++ b/libdwfl/frame_unwind.c @@ -43,21 +43,21 @@ error. */ #define DWARF_EXPR_STEPS_MAX 0x1000 -bool +int internal_function __libdwfl_frame_reg_get (Dwfl_Frame *state, unsigned regno, Dwarf_Addr *val) { Ebl *ebl = state->thread->process->ebl; if (! ebl_dwarf_to_regno (ebl, ®no)) - return false; + return -1; if (regno >= ebl_frame_nregs (ebl)) - return false; + return -1; if ((state->regs_set[regno / sizeof (*state->regs_set) / 8] & ((uint64_t) 1U << (regno % (sizeof (*state->regs_set) * 8)))) == 0) - return false; + return 1; if (val) *val = state->regs[regno]; - return true; + return 0; } bool @@ -78,17 +78,6 @@ __libdwfl_frame_reg_set (Dwfl_Frame *state, unsigned regno, Dwarf_Addr val) return true; } -static bool -state_get_reg (Dwfl_Frame *state, unsigned regno, Dwarf_Addr *val) -{ - if (! __libdwfl_frame_reg_get (state, regno, val)) - { - __libdwfl_seterrno (DWFL_E_INVALID_REGISTER); - return false; - } - return true; -} - static int bra_compar (const void *key_voidp, const void *elem_voidp) { @@ -211,7 +200,7 @@ expr_eval (Dwfl_Frame *state, Dwarf_Frame *frame, const Dwarf_Op *ops, } break; case DW_OP_reg0 ... DW_OP_reg31: - if (! state_get_reg (state, op->atom - DW_OP_reg0, &val1) + if (INTUSE (dwfl_frame_reg) (state, op->atom - DW_OP_reg0, &val1) != 0 || ! push (val1)) { free (stack.addrs); @@ -219,14 +208,14 @@ expr_eval (Dwfl_Frame *state, Dwarf_Frame *frame, const Dwarf_Op *ops, } break; case DW_OP_regx: - if (! state_get_reg (state, op->number, &val1) || ! push (val1)) + if (INTUSE (dwfl_frame_reg) (state, op->number, &val1) != 0 || ! push (val1)) { free (stack.addrs); return false; } break; case DW_OP_breg0 ... DW_OP_breg31: - if (! state_get_reg (state, op->atom - DW_OP_breg0, &val1)) + if (INTUSE (dwfl_frame_reg) (state, op->atom - DW_OP_breg0, &val1) != 0) { free (stack.addrs); return false; @@ -239,7 +228,7 @@ expr_eval (Dwfl_Frame *state, Dwarf_Frame *frame, const Dwarf_Op *ops, } break; case DW_OP_bregx: - if (! state_get_reg (state, op->number, &val1)) + if (INTUSE (dwfl_frame_reg) (state, op->number, &val1) != 0) { free (stack.addrs); return false; @@ -591,7 +580,7 @@ handle_cfi (Dwfl_Frame *state, Dwarf_Addr pc, Dwarf_CFI *cfi, Dwarf_Addr bias) else if (reg_ops == NULL) { /* REGNO is same-value. */ - if (! state_get_reg (state, regno, ®val)) + if (INTUSE (dwfl_frame_reg) (state, regno, ®val) != 0) continue; } else @@ -638,9 +627,10 @@ handle_cfi (Dwfl_Frame *state, Dwarf_Addr pc, Dwarf_CFI *cfi, Dwarf_Addr bias) } if (unwound->pc_state == DWFL_FRAME_STATE_ERROR) { - if (__libdwfl_frame_reg_get (unwound, - frame->fde->cie->return_address_register, - &unwound->pc)) + int res = INTUSE (dwfl_frame_reg) (unwound, + frame->fde->cie->return_address_register, + &unwound->pc); + if (res == 0) { /* PPC32 __libc_start_main properly CFI-unwinds PC as zero. Currently none of the archs supported for unwinding have @@ -698,7 +688,7 @@ getfunc (int firstreg, unsigned nregs, Dwarf_Word *regs, void *arg) Dwfl_Frame *state = arg; assert (firstreg >= 0); while (nregs--) - if (! __libdwfl_frame_reg_get (state, firstreg++, regs++)) + if (INTUSE (dwfl_frame_reg) (state, firstreg++, regs++) != 0) return false; return true; } diff --git a/libdwfl/libdwfl.h b/libdwfl/libdwfl.h index b323e8fb..1230972c 100644 --- a/libdwfl/libdwfl.h +++ b/libdwfl/libdwfl.h @@ -798,6 +798,12 @@ int dwfl_getthread_frames (Dwfl *dwfl, pid_t tid, bool dwfl_frame_pc (Dwfl_Frame *state, Dwarf_Addr *pc, bool *isactivation) __nonnull_attribute__ (1, 2); +/* Get the value of the DWARF register number in the given frame. + Returns zero on success, -1 on error (invalud DWARF register + number) or 1 if the value of the register in the frame is unknown. */ +int dwfl_frame_reg (Dwfl_Frame *state, unsigned regno, Dwarf_Word *val) + __nonnull_attribute__ (1); + /* Return the internal debuginfod-client connection handle for the DWFL session. When the client connection has not yet been initialized, it will be done on the first call to this function. If elfutils is compiled without support for debuginfod, diff --git a/libdwfl/libdwflP.h b/libdwfl/libdwflP.h index 9f598370..964daad5 100644 --- a/libdwfl/libdwflP.h +++ b/libdwfl/libdwflP.h @@ -81,6 +81,7 @@ typedef struct Dwfl_Process Dwfl_Process; DWFL_ERROR (LIBEBL_BAD, N_("Internal error due to ebl")) \ DWFL_ERROR (CORE_MISSING, N_("Missing data in core file")) \ DWFL_ERROR (INVALID_REGISTER, N_("Invalid register")) \ + DWFL_ERROR (REGISTER_VAL_UNKNOWN, N_("Unknown register value")) \ DWFL_ERROR (PROCESS_MEMORY_READ, N_("Error reading process memory")) \ DWFL_ERROR (PROCESS_NO_ARCH, N_("Couldn't find architecture of any ELF")) \ DWFL_ERROR (PARSE_PROC, N_("Error parsing /proc filesystem")) \ @@ -277,13 +278,15 @@ struct Dwfl_Frame }; /* Fetch value from Dwfl_Frame->regs indexed by DWARF REGNO. - No error code is set if the function returns FALSE. */ -bool __libdwfl_frame_reg_get (Dwfl_Frame *state, unsigned regno, + No error code is set if the function returns 0, + -1 on error (invalud DWARF register number), + 1 if the value of the register in the frame is unknown. */ +int __libdwfl_frame_reg_get (Dwfl_Frame *state, unsigned regno, Dwarf_Addr *val) internal_function; /* Store value to Dwfl_Frame->regs indexed by DWARF REGNO. - No error code is set if the function returns FALSE. */ + No error code is set if the function returns TRUE. */ bool __libdwfl_frame_reg_set (Dwfl_Frame *state, unsigned regno, Dwarf_Addr val) internal_function; @@ -786,6 +789,7 @@ INTDECL (dwfl_getthread_frames) INTDECL (dwfl_getthreads) INTDECL (dwfl_thread_getframes) INTDECL (dwfl_frame_pc) +INTDECL (dwfl_frame_reg) INTDECL (dwfl_get_debuginfod_client) /* Leading arguments standard to callbacks passed a Dwfl_Module. */ diff --git a/libdwfl/linux-core-attach.c b/libdwfl/linux-core-attach.c index f68062f0..ee7afa40 100644 --- a/libdwfl/linux-core-attach.c +++ b/libdwfl/linux-core-attach.c @@ -257,7 +257,7 @@ core_set_initial_registers (Dwfl_Thread *thread, void *thread_arg_voidp) FIXME: It depends now on their order in core notes. FIXME: It uses private function. */ if (regno < nregs - && __libdwfl_frame_reg_get (thread->unwound, regno, NULL)) + && __libdwfl_frame_reg_get (thread->unwound, regno, NULL) == 0) continue; Dwarf_Word val; switch (regloc->bits) -- 2.37.1