From f303bc3e6ca29f0413376e38164dc5cdc0893d4b Mon Sep 17 00:00:00 2001 From: Yao Qi Date: Fri, 28 Nov 2014 15:19:12 +0800 Subject: [PATCH] Don't scan prologue past epilogue This patch is to stop prologue analysis past epilogue in for arm mode, while we've already had done the same to thumb mode (see thumb_instruction_restores_sp). This is useful to parse functions with empty body (epilogue follows prologue). gdb: 2014-12-12 Yao Qi * arm-tdep.c (arm_instruction_restores_sp): New function. (arm_analyze_prologue): Call arm_instruction_restores_sp. (arm_in_function_epilogue_p): Move code to arm_instruction_restores_sp. --- gdb/ChangeLog | 7 +++++++ gdb/arm-tdep.c | 53 +++++++++++++++++++++++++++++--------------------- 2 files changed, 38 insertions(+), 22 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index bdbe56b10ac..c444ce77c07 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,10 @@ +2014-12-12 Yao Qi + + * arm-tdep.c (arm_instruction_restores_sp): New function. + (arm_analyze_prologue): Call arm_instruction_restores_sp. + (arm_in_function_epilogue_p): Move code to + arm_instruction_restores_sp. + 2014-12-11 Doug Evans * cp-namespace.c (cp_lookup_nested_symbol): Fix comments. diff --git a/gdb/arm-tdep.c b/gdb/arm-tdep.c index 7ec3bff5007..34070452e17 100644 --- a/gdb/arm-tdep.c +++ b/gdb/arm-tdep.c @@ -1664,6 +1664,30 @@ arm_instruction_changes_pc (uint32_t this_instr) } } +/* Return 1 if the ARM instruction INSN restores SP in epilogue, 0 + otherwise. */ + +static int +arm_instruction_restores_sp (unsigned int insn) +{ + if (bits (insn, 28, 31) != INST_NV) + { + if ((insn & 0x0df0f000) == 0x0080d000 + /* ADD SP (register or immediate). */ + || (insn & 0x0df0f000) == 0x0040d000 + /* SUB SP (register or immediate). */ + || (insn & 0x0ffffff0) == 0x01a0d000 + /* MOV SP. */ + || (insn & 0x0fff0000) == 0x08bd0000 + /* POP (LDMIA). */ + || (insn & 0x0fff0000) == 0x049d0000) + /* POP of a single register. */ + return 1; + } + + return 0; +} + /* Analyze an ARM mode prologue starting at PROLOGUE_START and continuing no further than PROLOGUE_END. If CACHE is non-NULL, fill it in. Return the first address not recognized as a prologue @@ -1861,6 +1885,11 @@ arm_analyze_prologue (struct gdbarch *gdbarch, else if (arm_instruction_changes_pc (insn)) /* Don't scan past anything that might change control flow. */ break; + else if (arm_instruction_restores_sp (insn)) + { + /* Don't scan past the epilogue. */ + break; + } else if ((insn & 0xfe500000) == 0xe8100000 /* ldm */ && pv_is_register (regs[bits (insn, 16, 19)], ARM_SP_REGNUM)) /* Ignore block loads from the stack, potentially copying @@ -3351,7 +3380,7 @@ arm_in_function_epilogue_p (struct gdbarch *gdbarch, CORE_ADDR pc) { enum bfd_endian byte_order_for_code = gdbarch_byte_order_for_code (gdbarch); unsigned int insn; - int found_return, found_stack_adjust; + int found_return; CORE_ADDR func_start, func_end; if (arm_pc_is_thumb (gdbarch, pc)) @@ -3391,28 +3420,8 @@ arm_in_function_epilogue_p (struct gdbarch *gdbarch, CORE_ADDR pc) if (pc < func_start + 4) return 0; - found_stack_adjust = 0; insn = read_memory_unsigned_integer (pc - 4, 4, byte_order_for_code); - if (bits (insn, 28, 31) != INST_NV) - { - if ((insn & 0x0df0f000) == 0x0080d000) - /* ADD SP (register or immediate). */ - found_stack_adjust = 1; - else if ((insn & 0x0df0f000) == 0x0040d000) - /* SUB SP (register or immediate). */ - found_stack_adjust = 1; - else if ((insn & 0x0ffffff0) == 0x01a0d000) - /* MOV SP. */ - found_stack_adjust = 1; - else if ((insn & 0x0fff0000) == 0x08bd0000) - /* POP (LDMIA). */ - found_stack_adjust = 1; - else if ((insn & 0x0fff0000) == 0x049d0000) - /* POP of a single register. */ - found_stack_adjust = 1; - } - - if (found_stack_adjust) + if (arm_instruction_restores_sp (insn)) return 1; return 0; -- 2.30.2