From b597c318b86b5ad2bca1f72ee8c0fbe33cbb7dad Mon Sep 17 00:00:00 2001 From: Yao Qi Date: Sun, 28 Dec 2014 16:12:53 +0800 Subject: always read synthetic pointers as signed integers I see the error message "access outside bounds of object referenced via synthetic pointer" in the two fails below of mips gdb testing print d[-2]^M access outside bounds of object referenced via synthetic pointer^M (gdb) FAIL: gdb.dwarf2/implptrconst.exp: print d[-2] (gdb) print/d p[-1]^M access outside bounds of object referenced via synthetic pointer^M (gdb) FAIL: gdb.dwarf2/implptrpiece.exp: print/d p[-1] in the first test, 'd[-2]' is processed by GDB as '* (&d[-2])'. 'd' is a synthetic pointer, so its value is zero, the address of 'd[-2]' is -2. In dwarf2loc.c:indirect_pieced_value, /* This is an offset requested by GDB, such as value subscripts. However, due to how synthetic pointers are implemented, this is always presented to us as a pointer type. This means we have to sign-extend it manually as appropriate. */ byte_offset = value_as_address (value); if (TYPE_LENGTH (value_type (value)) < sizeof (LONGEST)) byte_offset = gdb_sign_extend (byte_offset, 8 * TYPE_LENGTH (value_type (value))); byte_offset += piece->v.ptr.offset; We know that the value is really an offset instead of address, so the fix is to extract the value as an (signed) offset. gdb: 2015-01-08 Pedro Alves Yao Qi * dwarf2loc.c (indirect_pieced_value): Don't call gdb_sign_extend. Call extract_signed_integer instead. * utils.c (gdb_sign_extend): Remove. * utils.h (gdb_sign_extend): Remove declaration. --- gdb/utils.c | 17 ----------------- 1 file changed, 17 deletions(-) (limited to 'gdb/utils.c') diff --git a/gdb/utils.c b/gdb/utils.c index 084db87..72b1e2a 100644 --- a/gdb/utils.c +++ b/gdb/utils.c @@ -3021,23 +3021,6 @@ align_down (ULONGEST v, int n) return (v & -n); } -/* See utils.h. */ - -LONGEST -gdb_sign_extend (LONGEST value, int bit) -{ - gdb_assert (bit >= 1 && bit <= 8 * sizeof (LONGEST)); - - if (((value >> (bit - 1)) & 1) != 0) - { - LONGEST signbit = ((LONGEST) 1) << (bit - 1); - - value = (value ^ signbit) - signbit; - } - - return value; -} - /* Allocation function for the libiberty hash table which uses an obstack. The obstack is passed as DATA. */ -- cgit v1.1