/* Saved registers. */
CORE_ADDR saved_regs[AMD64_NUM_SAVED_REGS];
CORE_ADDR saved_sp;
+ int saved_sp_reg;
/* Do we have a frame? */
int frameless_p;
for (i = 0; i < AMD64_NUM_SAVED_REGS; i++)
cache->saved_regs[i] = -1;
cache->saved_sp = 0;
+ cache->saved_sp_reg = -1;
/* Frameless until proven otherwise. */
cache->frameless_p = 1;
return cache;
}
+/* GCC 4.4 and later, can put code in the prologue to realign the
+ stack pointer. Check whether PC points to such code, and update
+ CACHE accordingly. Return the first instruction after the code
+ sequence or CURRENT_PC, whichever is smaller. If we don't
+ recognize the code, return PC. */
+
+static CORE_ADDR
+amd64_analyze_stack_align (CORE_ADDR pc, CORE_ADDR current_pc,
+ struct amd64_frame_cache *cache)
+{
+ /* There are 2 code sequences to re-align stack before the frame
+ gets set up:
+
+ 1. Use a caller-saved saved register:
+
+ leaq 8(%rsp), %reg
+ andq $-XXX, %rsp
+ pushq -8(%reg)
+
+ 2. Use a callee-saved saved register:
+
+ pushq %reg
+ leaq 16(%rsp), %reg
+ andq $-XXX, %rsp
+ pushq -8(%reg)
+
+ "andq $-XXX, %rsp" can be either 4 bytes or 7 bytes:
+
+ 0x48 0x83 0xe4 0xf0 andq $-16, %rsp
+ 0x48 0x81 0xe4 0x00 0xff 0xff 0xff andq $-256, %rsp
+ */
+
+ gdb_byte buf[18];
+ int reg, r;
+ int offset, offset_and;
+ static int regnums[16] = {
+ AMD64_RAX_REGNUM, /* %rax */
+ AMD64_RCX_REGNUM, /* %rcx */
+ AMD64_RDX_REGNUM, /* %rdx */
+ AMD64_RBX_REGNUM, /* %rbx */
+ AMD64_RSP_REGNUM, /* %rsp */
+ AMD64_RBP_REGNUM, /* %rbp */
+ AMD64_RSI_REGNUM, /* %rsi */
+ AMD64_RDI_REGNUM, /* %rdi */
+ AMD64_R8_REGNUM, /* %r8 */
+ AMD64_R9_REGNUM, /* %r9 */
+ AMD64_R10_REGNUM, /* %r10 */
+ AMD64_R11_REGNUM, /* %r11 */
+ AMD64_R12_REGNUM, /* %r12 */
+ AMD64_R13_REGNUM, /* %r13 */
+ AMD64_R14_REGNUM, /* %r14 */
+ AMD64_R15_REGNUM, /* %r15 */
+ };
+
+ if (target_read_memory (pc, buf, sizeof buf))
+ return pc;
+
+ /* Check caller-saved saved register. The first instruction has
+ to be "leaq 8(%rsp), %reg". */
+ if ((buf[0] & 0xfb) == 0x48
+ && buf[1] == 0x8d
+ && buf[3] == 0x24
+ && buf[4] == 0x8)
+ {
+ /* MOD must be binary 10 and R/M must be binary 100. */
+ if ((buf[2] & 0xc7) != 0x44)
+ return pc;
+
+ /* REG has register number. */
+ reg = (buf[2] >> 3) & 7;
+
+ /* Check the REX.R bit. */
+ if (buf[0] == 0x4c)
+ reg += 8;
+
+ offset = 5;
+ }
+ else
+ {
+ /* Check callee-saved saved register. The first instruction
+ has to be "pushq %reg". */
+ reg = 0;
+ if ((buf[0] & 0xf8) == 0x50)
+ offset = 0;
+ else if ((buf[0] & 0xf6) == 0x40
+ && (buf[1] & 0xf8) == 0x50)
+ {
+ /* Check the REX.B bit. */
+ if ((buf[0] & 1) != 0)
+ reg = 8;
+
+ offset = 1;
+ }
+ else
+ return pc;
+
+ /* Get register. */
+ reg += buf[offset] & 0x7;
+
+ offset++;
+
+ /* The next instruction has to be "leaq 16(%rsp), %reg". */
+ if ((buf[offset] & 0xfb) != 0x48
+ || buf[offset + 1] != 0x8d
+ || buf[offset + 3] != 0x24
+ || buf[offset + 4] != 0x10)
+ return pc;
+
+ /* MOD must be binary 10 and R/M must be binary 100. */
+ if ((buf[offset + 2] & 0xc7) != 0x44)
+ return pc;
+
+ /* REG has register number. */
+ r = (buf[offset + 2] >> 3) & 7;
+
+ /* Check the REX.R bit. */
+ if (buf[offset] == 0x4c)
+ r += 8;
+
+ /* Registers in pushq and leaq have to be the same. */
+ if (reg != r)
+ return pc;
+
+ offset += 5;
+ }
+
+ /* Rigister can't be %rsp nor %rbp. */
+ if (reg == 4 || reg == 5)
+ return pc;
+
+ /* The next instruction has to be "andq $-XXX, %rsp". */
+ if (buf[offset] != 0x48
+ || buf[offset + 2] != 0xe4
+ || (buf[offset + 1] != 0x81 && buf[offset + 1] != 0x83))
+ return pc;
+
+ offset_and = offset;
+ offset += buf[offset + 1] == 0x81 ? 7 : 4;
+
+ /* The next instruction has to be "pushq -8(%reg)". */
+ r = 0;
+ if (buf[offset] == 0xff)
+ offset++;
+ else if ((buf[offset] & 0xf6) == 0x40
+ && buf[offset + 1] == 0xff)
+ {
+ /* Check the REX.B bit. */
+ if ((buf[offset] & 0x1) != 0)
+ r = 8;
+ offset += 2;
+ }
+ else
+ return pc;
+
+ /* 8bit -8 is 0xf8. REG must be binary 110 and MOD must be binary
+ 01. */
+ if (buf[offset + 1] != 0xf8
+ || (buf[offset] & 0xf8) != 0x70)
+ return pc;
+
+ /* R/M has register. */
+ r += buf[offset] & 7;
+
+ /* Registers in leaq and pushq have to be the same. */
+ if (reg != r)
+ return pc;
+
+ if (current_pc > pc + offset_and)
+ cache->saved_sp_reg = regnums[reg];
+
+ return min (pc + offset + 2, current_pc);
+}
+
/* Do a limited analysis of the prologue at PC and update CACHE
accordingly. Bail out early if CURRENT_PC is reached. Return the
address where the analysis stopped.
if (current_pc <= pc)
return current_pc;
+ pc = amd64_analyze_stack_align (pc, current_pc, cache);
+
op = read_memory_unsigned_integer (pc, 1);
if (op == 0x55) /* pushq %rbp */
if (cache->pc != 0)
amd64_analyze_prologue (cache->pc, get_frame_pc (this_frame), cache);
+ if (cache->saved_sp_reg != -1)
+ {
+ /* Stack pointer has been saved. */
+ get_frame_register (this_frame, cache->saved_sp_reg, buf);
+ cache->saved_sp = extract_unsigned_integer(buf, 8);
+ }
+
if (cache->frameless_p)
{
/* We didn't find a valid frame. If we're at the start of a
at the stack pointer. For truly "frameless" functions this
might work too. */
- get_frame_register (this_frame, AMD64_RSP_REGNUM, buf);
- cache->base = extract_unsigned_integer (buf, 8) + cache->sp_offset;
+ if (cache->saved_sp_reg != -1)
+ {
+ /* We're halfway aligning the stack. */
+ cache->base = ((cache->saved_sp - 8) & 0xfffffffffffffff0LL) - 8;
+ cache->saved_regs[AMD64_RIP_REGNUM] = cache->saved_sp - 8;
+
+ /* This will be added back below. */
+ cache->saved_regs[AMD64_RIP_REGNUM] -= cache->base;
+ }
+ else
+ {
+ get_frame_register (this_frame, AMD64_RSP_REGNUM, buf);
+ cache->base = extract_unsigned_integer (buf, 8) + cache->sp_offset;
+ }
}
else
{
/* For normal frames, %rip is stored at 8(%rbp). If we don't have a
frame we find it at the same offset from the reconstructed base
- address. */
- cache->saved_regs[AMD64_RIP_REGNUM] = 8;
+ address. If we're halfway aligning the stack, %rip is handled
+ differently (see above). */
+ if (!cache->frameless_p || cache->saved_sp_reg == -1)
+ cache->saved_regs[AMD64_RIP_REGNUM] = 8;
/* Adjust all the saved registers such that they contain addresses
instead of offsets. */
projects / deliverable / binutils-gdb.git / blobdiff