diff options
Diffstat (limited to 'gcc/tree-ssa-strlen.c')
| -rw-r--r-- | gcc/tree-ssa-strlen.c | 98 |
1 files changed, 65 insertions, 33 deletions
diff --git a/gcc/tree-ssa-strlen.c b/gcc/tree-ssa-strlen.c index 141115ed12b..9c72d122bbe 100644 --- a/gcc/tree-ssa-strlen.c +++ b/gcc/tree-ssa-strlen.c @@ -61,7 +61,13 @@ struct strinfo tree length; /* Any of the corresponding pointers for querying alias oracle. */ tree ptr; - /* Statement for delayed length computation. */ + /* This is used for two things: + + - To record the statement that should be used for delayed length + computations. We maintain the invariant that all related strinfos + have delayed lengths or none do. + + - To record the malloc or calloc call that produced this result. */ gimple *stmt; /* Pointer to '\0' if known, if NULL, it can be computed as ptr + length. */ @@ -156,6 +162,19 @@ get_strinfo (int idx) return (*stridx_to_strinfo)[idx]; } +/* Get the next strinfo in the chain after SI, or null if none. */ + +static inline strinfo * +get_next_strinfo (strinfo *si) +{ + if (si->next == 0) + return NULL; + strinfo *nextsi = get_strinfo (si->next); + if (nextsi == NULL || nextsi->first != si->first || nextsi->prev != si->idx) + return NULL; + return nextsi; +} + /* Helper function for get_stridx. */ static int @@ -438,6 +457,45 @@ set_strinfo (int idx, strinfo *si) (*stridx_to_strinfo)[idx] = si; } +/* Return the first strinfo in the related strinfo chain + if all strinfos in between belong to the chain, otherwise NULL. */ + +static strinfo * +verify_related_strinfos (strinfo *origsi) +{ + strinfo *si = origsi, *psi; + + if (origsi->first == 0) + return NULL; + for (; si->prev; si = psi) + { + if (si->first != origsi->first) + return NULL; + psi = get_strinfo (si->prev); + if (psi == NULL) + return NULL; + if (psi->next != si->idx) + return NULL; + } + if (si->idx != si->first) + return NULL; + return si; +} + +/* Set SI's endptr to ENDPTR and compute its length based on SI->ptr. + Use LOC for folding. */ + +static void +set_endptr_and_length (location_t loc, strinfo *si, tree endptr) +{ + si->endptr = endptr; + si->stmt = NULL; + tree start_as_size = fold_convert_loc (loc, size_type_node, si->ptr); + tree end_as_size = fold_convert_loc (loc, size_type_node, endptr); + si->length = fold_build2_loc (loc, MINUS_EXPR, size_type_node, + end_as_size, start_as_size); +} + /* Return string length, or NULL if it can't be computed. */ static tree @@ -533,12 +591,12 @@ get_string_length (strinfo *si) case BUILT_IN_STPCPY_CHK_CHKP: gcc_assert (lhs != NULL_TREE); loc = gimple_location (stmt); - si->endptr = lhs; - si->stmt = NULL; - lhs = fold_convert_loc (loc, size_type_node, lhs); - si->length = fold_convert_loc (loc, size_type_node, si->ptr); - si->length = fold_build2_loc (loc, MINUS_EXPR, size_type_node, - lhs, si->length); + set_endptr_and_length (loc, si, lhs); + for (strinfo *chainsi = verify_related_strinfos (si); + chainsi != NULL; + chainsi = get_next_strinfo (chainsi)) + if (chainsi->length == NULL) + set_endptr_and_length (loc, chainsi, lhs); break; case BUILT_IN_MALLOC: break; @@ -607,32 +665,6 @@ unshare_strinfo (strinfo *si) return nsi; } -/* Return first strinfo in the related strinfo chain - if all strinfos in between belong to the chain, otherwise - NULL. */ - -static strinfo * -verify_related_strinfos (strinfo *origsi) -{ - strinfo *si = origsi, *psi; - - if (origsi->first == 0) - return NULL; - for (; si->prev; si = psi) - { - if (si->first != origsi->first) - return NULL; - psi = get_strinfo (si->prev); - if (psi == NULL) - return NULL; - if (psi->next != si->idx) - return NULL; - } - if (si->idx != si->first) - return NULL; - return si; -} - /* Attempt to create a new strinfo for BASESI + OFF, or find existing strinfo if there is any. Return it's idx, or 0 if no strinfo has been created. */ |