diff options
| -rw-r--r-- | include/sframe.h | 4 | ||||
| -rw-r--r-- | libsframe/doc/sframe-spec.texi | 6 | ||||
| -rw-r--r-- | libsframe/sframe.c | 78 |
3 files changed, 62 insertions, 26 deletions
diff --git a/include/sframe.h b/include/sframe.h index c3dbb3a..cdf275f 100644 --- a/include/sframe.h +++ b/include/sframe.h @@ -117,8 +117,8 @@ extern "C" /* Unwinders perform a (PC >= FRE_START_ADDR) to look up a matching FRE. */ #define SFRAME_FDE_TYPE_PCINC 0 -/* Unwinders perform a (PC & FRE_START_ADDR_AS_MASK >= FRE_START_ADDR_AS_MASK) - to look up a matching FRE. */ +/* Unwinders perform a (PC % REP_BLOCK_SIZE >= FRE_START_ADDR) to look up a + matching FRE. */ #define SFRAME_FDE_TYPE_PCMASK 1 typedef struct sframe_preamble diff --git a/libsframe/doc/sframe-spec.texi b/libsframe/doc/sframe-spec.texi index 5155410..a37a6f9 100644 --- a/libsframe/doc/sframe-spec.texi +++ b/libsframe/doc/sframe-spec.texi @@ -451,8 +451,10 @@ entries and trampolines. @item SFRAME_FDE_TYPE_PCMASK @tab 1 @tab Unwinders perform a @* -(PC & FRE_START_ADDR_AS_MASK >= FRE_START_ADDR_AS_MASK) -to look up a matching FRE. +(PC % REP_BLOCK_SIZE @* + >= FRE_START_ADDR) +to look up a matching FRE. REP_BLOCK_SIZE is the size in bytes of the +repeating block of program instructions. @end multitable diff --git a/libsframe/sframe.c b/libsframe/sframe.c index 2914243..fd966cf 100644 --- a/libsframe/sframe.c +++ b/libsframe/sframe.c @@ -362,6 +362,53 @@ sframe_decoder_get_funcdesc_at_index (sframe_decoder_ctx *ctx, return fdep; } +/* Check whether for the given FDEP, the SFrame Frame Row Entry identified via + the START_IP_OFFSET and the END_IP_OFFSET, provides the stack trace + information for the PC. */ + +static bool +sframe_fre_check_range_p (sframe_func_desc_entry *fdep, + int32_t start_ip_offset, int32_t end_ip_offset, + int32_t pc) +{ + int32_t start_ip, end_ip; + int32_t func_start_addr; + uint32_t rep_block_size; + uint32_t fde_type; + int32_t masked_pc; + bool mask_p; + bool ret; + + ret = false; + /* FIXME - the rep_block_size should be encoded in the format somehow. For + AMD64, each pltN entry stub in .plt is 16 bytes. */ + rep_block_size = 16; + + if (!fdep) + return ret; + + func_start_addr = fdep->sfde_func_start_address; + fde_type = sframe_get_fde_type (fdep); + mask_p = (fde_type == SFRAME_FDE_TYPE_PCMASK); + + if (!mask_p) + { + start_ip = start_ip_offset + func_start_addr; + end_ip = end_ip_offset + func_start_addr; + ret = ((start_ip <= pc) && (end_ip >= pc)); + } + else + { + /* For FDEs for repetitive pattern of insns, we need to return the FRE + where pc % rep_block_size is between start_ip_offset and + end_ip_offset. */ + masked_pc = pc % rep_block_size; + ret = ((start_ip_offset <= masked_pc) && (end_ip_offset >= masked_pc)); + } + + return ret; +} + static int flip_fre (char *fp, uint32_t fre_type, size_t *fre_size) { @@ -1056,19 +1103,14 @@ sframe_find_fre (sframe_decoder_ctx *ctx, int32_t pc, { sframe_frame_row_entry cur_fre; sframe_func_desc_entry *fdep; - uint32_t fre_type, fde_type; - uint32_t end_ip_offset, i; - int32_t start_ip, end_ip; + uint32_t fre_type, fde_type, i; + int32_t start_ip_offset; int32_t func_start_addr; + int32_t end_ip_offset; const char *fres; size_t size = 0; int err = 0; - /* For regular FDEs (i.e. fde_type SFRAME_FDE_TYPE_PCINC), - where the start address in the FRE is an offset from start pc, - use a bitmask with all bits set so that none of the address bits are - ignored. In this case, we need to return the FRE where - (PC >= FRE_START_ADDR) */ - uint64_t bitmask = 0xffffffff; + bool mask_p; if ((ctx == NULL) || (frep == NULL)) return sframe_set_errno (&err, SFRAME_ERR_INVAL); @@ -1080,14 +1122,7 @@ sframe_find_fre (sframe_decoder_ctx *ctx, int32_t pc, fre_type = sframe_get_fre_type (fdep); fde_type = sframe_get_fde_type (fdep); - - /* For FDEs for repetitive pattern of insns, we need to return the FRE - such that (PC & FRE_START_ADDR_AS_MASK >= FRE_START_ADDR_AS_MASK). - so, update the bitmask to the start address. */ - /* FIXME - the bitmask should be picked per ABI or encoded in the format - somehow. For AMD64, the pltN entry stub is 16 bytes. */ - if (fde_type == SFRAME_FDE_TYPE_PCMASK) - bitmask = 0xf; + mask_p = (fde_type == SFRAME_FDE_TYPE_PCMASK); fres = ctx->sfd_fres + fdep->sfde_func_start_fre_off; func_start_addr = fdep->sfde_func_start_address; @@ -1098,15 +1133,14 @@ sframe_find_fre (sframe_decoder_ctx *ctx, int32_t pc, if (err) return sframe_set_errno (&err, SFRAME_ERR_FRE_INVAL); - start_ip = func_start_addr + cur_fre.fre_start_addr; + start_ip_offset = cur_fre.fre_start_addr; end_ip_offset = sframe_fre_get_end_ip_offset (fdep, i, fres + size); - end_ip = func_start_addr + end_ip_offset; - if ((start_ip & bitmask) > (pc & bitmask)) + /* First FRE's start_ip must be more than pc for regular SFrame FDEs. */ + if (i == 0 && !mask_p && (start_ip_offset + func_start_addr) > pc) return sframe_set_errno (&err, SFRAME_ERR_FRE_INVAL); - if (((start_ip & bitmask) <= (pc & bitmask)) - && (end_ip & bitmask) >= (pc & bitmask)) + if (sframe_fre_check_range_p (fdep, start_ip_offset, end_ip_offset, pc)) { sframe_frame_row_entry_copy (frep, &cur_fre); return 0; |