diff options
Diffstat (limited to 'gdb/parse.c')
| -rw-r--r-- | gdb/parse.c | 74 |
1 files changed, 54 insertions, 20 deletions
diff --git a/gdb/parse.c b/gdb/parse.c index 4090302..2ce1ea7 100644 --- a/gdb/parse.c +++ b/gdb/parse.c @@ -200,27 +200,62 @@ write_exp_elt_intern (expelt) } /* Add a string constant to the end of the expression. - Follow it by its length in bytes, as a separate exp_element. */ + + String constants are stored by first writing an expression element + that contains the length of the string, then stuffing the string + constant itself into however many expression elements are needed + to hold it, and then writing another expression element that contains + the length of the string. I.E. an expression element at each end of + the string records the string length, so you can skip over the + expression elements containing the actual string bytes from either + end of the string. Note that this also allows gdb to handle + strings with embedded null bytes, as is required for some languages. + + Don't be fooled by the fact that the string is null byte terminated, + this is strictly for the convenience of debugging gdb itself. Gdb + Gdb does not depend up the string being null terminated, since the + actual length is recorded in expression elements at each end of the + string. The null byte is taken into consideration when computing how + many expression elements are required to hold the string constant, of + course. */ + void write_exp_string (str) struct stoken str; { register int len = str.length; - register int lenelt - = (len + sizeof (union exp_element)) / sizeof (union exp_element); + register int lenelt; + register char *strdata; - expout_ptr += lenelt; + /* Compute the number of expression elements required to hold the string + (including a null byte terminator), along with one expression element + at each end to record the actual string length (not including the + null byte terminator). */ - if (expout_ptr >= expout_size) + lenelt = 2 + (len + sizeof (union exp_element)) / sizeof (union exp_element); + + /* Ensure that we have enough available expression elements to store + everything. */ + + if ((expout_ptr + lenelt) >= expout_size) { - expout_size = max (expout_size * 2, expout_ptr + 10); + expout_size = max (expout_size * 2, expout_ptr + lenelt + 10); expout = (struct expression *) xrealloc ((char *) expout, (sizeof (struct expression) + (expout_size * sizeof (union exp_element)))); } - memcpy ((char *) &expout->elts[expout_ptr - lenelt], str.ptr, len); - ((char *) &expout->elts[expout_ptr - lenelt])[len] = 0; + + /* Write the leading length expression element (which advances the current + expression element index), then write the string constant followed by a + terminating null byte, and then write the trailing length expression + element. */ + + write_exp_elt_longcst ((LONGEST) len); + strdata = (char *) &expout->elts[expout_ptr]; + memcpy (strdata, str.ptr, len); + *(strdata + len) = '\0'; + expout_ptr += lenelt - 2; write_exp_elt_longcst ((LONGEST) len); } @@ -268,7 +303,7 @@ length_of_subexp (expr, endpos) register int args = 0; register int i; - if (endpos < 0) + if (endpos < 1) error ("?error in length_of_subexp"); i = (int) expr->elts[endpos - 1].opcode; @@ -277,7 +312,7 @@ length_of_subexp (expr, endpos) { /* C++ */ case OP_SCOPE: - oplen = 4 + ((expr->elts[endpos - 2].longconst + oplen = 5 + ((longest_to_int (expr->elts[endpos - 2].longconst) + sizeof (union exp_element)) / sizeof (union exp_element)); break; @@ -298,13 +333,12 @@ length_of_subexp (expr, endpos) case OP_FUNCALL: oplen = 3; - args = 1 + expr->elts[endpos - 2].longconst; + args = 1 + longest_to_int (expr->elts[endpos - 2].longconst); break; case UNOP_MAX: case UNOP_MIN: oplen = 3; - args = 0; break; case BINOP_VAL: @@ -329,9 +363,10 @@ length_of_subexp (expr, endpos) case STRUCTOP_STRUCT: case STRUCTOP_PTR: args = 1; + /* fall through */ case OP_M2_STRING: case OP_STRING: - oplen = 3 + ((expr->elts[endpos - 2].longconst + oplen = 4 + ((longest_to_int (expr->elts[endpos - 2].longconst) + sizeof (union exp_element)) / sizeof (union exp_element)); break; @@ -343,7 +378,7 @@ length_of_subexp (expr, endpos) /* Modula-2 */ case BINOP_MULTI_SUBSCRIPT: oplen=3; - args = 1 + expr->elts[endpos- 2].longconst; + args = 1 + longest_to_int (expr->elts[endpos- 2].longconst); break; case BINOP_ASSIGN_MODIFY: @@ -395,7 +430,7 @@ prefixify_subexp (inexpr, outexpr, inend, outbeg) { /* C++ */ case OP_SCOPE: - oplen = 4 + ((inexpr->elts[inend - 2].longconst + oplen = 5 + ((longest_to_int (inexpr->elts[inend - 2].longconst) + sizeof (union exp_element)) / sizeof (union exp_element)); break; @@ -416,13 +451,12 @@ prefixify_subexp (inexpr, outexpr, inend, outbeg) case OP_FUNCALL: oplen = 3; - args = 1 + inexpr->elts[inend - 2].longconst; + args = 1 + longest_to_int (inexpr->elts[inend - 2].longconst); break; case UNOP_MIN: case UNOP_MAX: oplen = 3; - args = 0; break; case UNOP_CAST: @@ -446,12 +480,12 @@ prefixify_subexp (inexpr, outexpr, inend, outbeg) case STRUCTOP_STRUCT: case STRUCTOP_PTR: args = 1; + /* fall through */ case OP_M2_STRING: case OP_STRING: - oplen = 3 + ((inexpr->elts[inend - 2].longconst + oplen = 4 + ((longest_to_int (inexpr->elts[inend - 2].longconst) + sizeof (union exp_element)) / sizeof (union exp_element)); - break; case TERNOP_COND: @@ -466,7 +500,7 @@ prefixify_subexp (inexpr, outexpr, inend, outbeg) /* Modula-2 */ case BINOP_MULTI_SUBSCRIPT: oplen=3; - args = 1 + inexpr->elts[inend - 2].longconst; + args = 1 + longest_to_int (inexpr->elts[inend - 2].longconst); break; /* C++ */ |