diff options
Diffstat (limited to 'gcc/tree-ssa-strlen.cc')
| -rw-r--r-- | gcc/tree-ssa-strlen.cc | 53 |
1 files changed, 31 insertions, 22 deletions
diff --git a/gcc/tree-ssa-strlen.cc b/gcc/tree-ssa-strlen.cc index 8b7ef91..083a10d 100644 --- a/gcc/tree-ssa-strlen.cc +++ b/gcc/tree-ssa-strlen.cc @@ -281,14 +281,14 @@ public: gimple *stmt, unsigned lenrange[3], bool *nulterm, bool *allnul, bool *allnonnul); - bool count_nonzero_bytes (tree exp, + bool count_nonzero_bytes (tree exp, tree vuse, gimple *stmt, unsigned HOST_WIDE_INT offset, unsigned HOST_WIDE_INT nbytes, unsigned lenrange[3], bool *nulterm, bool *allnul, bool *allnonnul, ssa_name_limit_t &snlim); - bool count_nonzero_bytes_addr (tree exp, + bool count_nonzero_bytes_addr (tree exp, tree vuse, gimple *stmt, unsigned HOST_WIDE_INT offset, unsigned HOST_WIDE_INT nbytes, @@ -4531,8 +4531,8 @@ nonzero_bytes_for_type (tree type, unsigned lenrange[3], } /* Recursively determine the minimum and maximum number of leading nonzero - bytes in the representation of EXP and set LENRANGE[0] and LENRANGE[1] - to each. + bytes in the representation of EXP at memory state VUSE and set + LENRANGE[0] and LENRANGE[1] to each. Sets LENRANGE[2] to the total size of the access (which may be less than LENRANGE[1] when what's being referenced by EXP is a pointer rather than an array). @@ -4546,7 +4546,7 @@ nonzero_bytes_for_type (tree type, unsigned lenrange[3], Returns true on success and false otherwise. */ bool -strlen_pass::count_nonzero_bytes (tree exp, gimple *stmt, +strlen_pass::count_nonzero_bytes (tree exp, tree vuse, gimple *stmt, unsigned HOST_WIDE_INT offset, unsigned HOST_WIDE_INT nbytes, unsigned lenrange[3], bool *nulterm, @@ -4566,22 +4566,23 @@ strlen_pass::count_nonzero_bytes (tree exp, gimple *stmt, exact value is not known) recurse once to set the range for an arbitrary constant. */ exp = build_int_cst (type, 1); - return count_nonzero_bytes (exp, stmt, + return count_nonzero_bytes (exp, vuse, stmt, offset, 1, lenrange, nulterm, allnul, allnonnul, snlim); } - gimple *stmt = SSA_NAME_DEF_STMT (exp); - if (gimple_assign_single_p (stmt)) + gimple *g = SSA_NAME_DEF_STMT (exp); + if (gimple_assign_single_p (g)) { - exp = gimple_assign_rhs1 (stmt); + exp = gimple_assign_rhs1 (g); if (!DECL_P (exp) && TREE_CODE (exp) != CONSTRUCTOR && TREE_CODE (exp) != MEM_REF) return false; /* Handle DECLs, CONSTRUCTOR and MEM_REF below. */ + stmt = g; } - else if (gimple_code (stmt) == GIMPLE_PHI) + else if (gimple_code (g) == GIMPLE_PHI) { /* Avoid processing an SSA_NAME that has already been visited or if an SSA_NAME limit has been reached. Indicate success @@ -4590,11 +4591,11 @@ strlen_pass::count_nonzero_bytes (tree exp, gimple *stmt, return res > 0; /* Determine the minimum and maximum from the PHI arguments. */ - unsigned int n = gimple_phi_num_args (stmt); + unsigned int n = gimple_phi_num_args (g); for (unsigned i = 0; i != n; i++) { - tree def = gimple_phi_arg_def (stmt, i); - if (!count_nonzero_bytes (def, stmt, + tree def = gimple_phi_arg_def (g, i); + if (!count_nonzero_bytes (def, vuse, g, offset, nbytes, lenrange, nulterm, allnul, allnonnul, snlim)) return false; @@ -4652,7 +4653,7 @@ strlen_pass::count_nonzero_bytes (tree exp, gimple *stmt, return false; /* Handle MEM_REF = SSA_NAME types of assignments. */ - return count_nonzero_bytes_addr (arg, stmt, + return count_nonzero_bytes_addr (arg, vuse, stmt, offset, nbytes, lenrange, nulterm, allnul, allnonnul, snlim); } @@ -4765,7 +4766,7 @@ strlen_pass::count_nonzero_bytes (tree exp, gimple *stmt, bytes that are pointed to by EXP, which should be a pointer. */ bool -strlen_pass::count_nonzero_bytes_addr (tree exp, gimple *stmt, +strlen_pass::count_nonzero_bytes_addr (tree exp, tree vuse, gimple *stmt, unsigned HOST_WIDE_INT offset, unsigned HOST_WIDE_INT nbytes, unsigned lenrange[3], bool *nulterm, @@ -4775,6 +4776,14 @@ strlen_pass::count_nonzero_bytes_addr (tree exp, gimple *stmt, int idx = get_stridx (exp, stmt); if (idx > 0) { + /* get_strinfo reflects string lengths before the current statement, + where the current statement is the outermost count_nonzero_bytes + stmt. If there are any stores in between stmt and that + current statement, the string length information might describe + something significantly different. */ + if (gimple_vuse (stmt) != vuse) + return false; + strinfo *si = get_strinfo (idx); if (!si) return false; @@ -4835,14 +4844,14 @@ strlen_pass::count_nonzero_bytes_addr (tree exp, gimple *stmt, } if (TREE_CODE (exp) == ADDR_EXPR) - return count_nonzero_bytes (TREE_OPERAND (exp, 0), stmt, + return count_nonzero_bytes (TREE_OPERAND (exp, 0), vuse, stmt, offset, nbytes, lenrange, nulterm, allnul, allnonnul, snlim); if (TREE_CODE (exp) == SSA_NAME) { - gimple *stmt = SSA_NAME_DEF_STMT (exp); - if (gimple_code (stmt) == GIMPLE_PHI) + gimple *g = SSA_NAME_DEF_STMT (exp); + if (gimple_code (g) == GIMPLE_PHI) { /* Avoid processing an SSA_NAME that has already been visited or if an SSA_NAME limit has been reached. Indicate success @@ -4851,11 +4860,11 @@ strlen_pass::count_nonzero_bytes_addr (tree exp, gimple *stmt, return res > 0; /* Determine the minimum and maximum from the PHI arguments. */ - unsigned int n = gimple_phi_num_args (stmt); + unsigned int n = gimple_phi_num_args (g); for (unsigned i = 0; i != n; i++) { - tree def = gimple_phi_arg_def (stmt, i); - if (!count_nonzero_bytes_addr (def, stmt, + tree def = gimple_phi_arg_def (g, i); + if (!count_nonzero_bytes_addr (def, vuse, g, offset, nbytes, lenrange, nulterm, allnul, allnonnul, snlim)) @@ -4903,7 +4912,7 @@ strlen_pass::count_nonzero_bytes (tree expr_or_type, gimple *stmt, ssa_name_limit_t snlim; tree expr = expr_or_type; - return count_nonzero_bytes (expr, stmt, + return count_nonzero_bytes (expr, gimple_vuse (stmt), stmt, 0, 0, lenrange, nulterm, allnul, allnonnul, snlim); } |