diff options
Diffstat (limited to 'gdb/amd64-tdep.c')
| -rw-r--r-- | gdb/amd64-tdep.c | 42 |
1 files changed, 37 insertions, 5 deletions
diff --git a/gdb/amd64-tdep.c b/gdb/amd64-tdep.c index 6289d21..41b9783 100644 --- a/gdb/amd64-tdep.c +++ b/gdb/amd64-tdep.c @@ -1764,15 +1764,47 @@ amd64_relocate_instruction (struct gdbarch *gdbarch, the user program would return to. */ if (insn[0] == 0xe8) { - gdb_byte push_buf[16]; - unsigned int ret_addr; + gdb_byte push_buf[32]; + CORE_ADDR ret_addr; + int i = 0; /* Where "ret" in the original code will return to. */ ret_addr = oldloc + insn_length; - push_buf[0] = 0x68; /* pushq $... */ - store_unsigned_integer (&push_buf[1], 4, byte_order, ret_addr); + + /* If pushing an address higher than or equal to 0x80000000, + avoid 'pushq', as that sign extends its 32-bit operand, which + would be incorrect. */ + if (ret_addr <= 0x7fffffff) + { + push_buf[0] = 0x68; /* pushq $... */ + store_unsigned_integer (&push_buf[1], 4, byte_order, ret_addr); + i = 5; + } + else + { + push_buf[i++] = 0x48; /* sub $0x8,%rsp */ + push_buf[i++] = 0x83; + push_buf[i++] = 0xec; + push_buf[i++] = 0x08; + + push_buf[i++] = 0xc7; /* movl $imm,(%rsp) */ + push_buf[i++] = 0x04; + push_buf[i++] = 0x24; + store_unsigned_integer (&push_buf[i], 4, byte_order, + ret_addr & 0xffffffff); + i += 4; + + push_buf[i++] = 0xc7; /* movl $imm,4(%rsp) */ + push_buf[i++] = 0x44; + push_buf[i++] = 0x24; + push_buf[i++] = 0x04; + store_unsigned_integer (&push_buf[i], 4, byte_order, + ret_addr >> 32); + i += 4; + } + gdb_assert (i <= sizeof (push_buf)); /* Push the push. */ - append_insns (to, 5, push_buf); + append_insns (to, i, push_buf); /* Convert the relative call to a relative jump. */ insn[0] = 0xe9; |