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[PATCH 3/8] [AArch64] Only access inferior registers when creating a frame cache
- From: Pierre Langlois <pierre dot langlois at arm dot com>
- To: gdb-patches at sourceware dot org
- Cc: Pierre Langlois <pierre dot langlois at arm dot com>
- Date: Tue, 7 Jul 2015 13:51:53 +0100
- Subject: [PATCH 3/8] [AArch64] Only access inferior registers when creating a frame cache
- Authentication-results: sourceware.org; auth=none
- References: <1436273518-5959-1-git-send-email-pierre dot langlois at arm dot com>
This patch moves the address of the start of a function (func) and the
address from which it was called (prev_pc) into aarch64_prologue_cache.
The idea is to keep accesses to the inferior's registers into
aarch64_make_prologue_cache and aarch64_make_stub_cache.
gdb/ChangeLog:
* aarch64-tdep.c (aarch64_prologue_cache) <func, prev_pc>: New
fields.
(aarch64_scan_prologue): Set prev_pc.
(aarch64_make_prologue_cache): Set func.
(aarch64_make_stub_cache): Set prev_pc.
(aarch64_prologue_this_id): Remove local variables id, pc and
func. Read prev_pc and func from cache.
(aarch64_stub_this_id): Read prev_pc from cache.
---
gdb/aarch64-tdep.c | 25 +++++++++++++++++--------
1 file changed, 17 insertions(+), 8 deletions(-)
diff --git a/gdb/aarch64-tdep.c b/gdb/aarch64-tdep.c
index 90a63e9..6a38f18 100644
--- a/gdb/aarch64-tdep.c
+++ b/gdb/aarch64-tdep.c
@@ -148,6 +148,15 @@ static const char *const aarch64_v_register_names[] =
/* AArch64 prologue cache structure. */
struct aarch64_prologue_cache
{
+ /* The program counter at the start of the function. It is used to
+ identify this frame as a prologue frame. */
+ CORE_ADDR func;
+
+ /* The program counter at the time this frame was created; i.e. where
+ this function was called from. It is used to identify this frame as a
+ stub frame. */
+ CORE_ADDR prev_pc;
+
/* The stack pointer at the time this frame was created; i.e. the
caller's stack pointer when this function was called. It is used
to identify this frame. */
@@ -889,6 +898,8 @@ aarch64_scan_prologue (struct frame_info *this_frame,
CORE_ADDR prev_pc = get_frame_pc (this_frame);
struct gdbarch *gdbarch = get_frame_arch (this_frame);
+ cache->prev_pc = prev_pc;
+
/* Assume we do not find a frame. */
cache->framereg = -1;
cache->framesize = 0;
@@ -964,6 +975,8 @@ aarch64_make_prologue_cache (struct frame_info *this_frame, void **this_cache)
if (trad_frame_addr_p (cache->saved_regs, reg))
cache->saved_regs[reg].addr += cache->prev_sp;
+ cache->func = get_frame_func (this_frame);
+
return cache;
}
@@ -976,21 +989,16 @@ aarch64_prologue_this_id (struct frame_info *this_frame,
{
struct aarch64_prologue_cache *cache
= aarch64_make_prologue_cache (this_frame, this_cache);
- struct frame_id id;
- CORE_ADDR pc, func;
/* This is meant to halt the backtrace at "_start". */
- pc = get_frame_pc (this_frame);
- if (pc <= gdbarch_tdep (get_frame_arch (this_frame))->lowest_pc)
+ if (cache->prev_pc <= gdbarch_tdep (get_frame_arch (this_frame))->lowest_pc)
return;
/* If we've hit a wall, stop. */
if (cache->prev_sp == 0)
return;
- func = get_frame_func (this_frame);
- id = frame_id_build (cache->prev_sp, func);
- *this_id = id;
+ *this_id = frame_id_build (cache->prev_sp, cache->func);
}
/* Implement the "prev_register" frame_unwind method. */
@@ -1065,6 +1073,7 @@ aarch64_make_stub_cache (struct frame_info *this_frame, void **this_cache)
cache->prev_sp
= get_frame_register_unsigned (this_frame, AARCH64_SP_REGNUM);
+ cache->prev_pc = get_frame_pc (this_frame);
return cache;
}
@@ -1078,7 +1087,7 @@ aarch64_stub_this_id (struct frame_info *this_frame,
struct aarch64_prologue_cache *cache
= aarch64_make_stub_cache (this_frame, this_cache);
- *this_id = frame_id_build (cache->prev_sp, get_frame_pc (this_frame));
+ *this_id = frame_id_build (cache->prev_sp, cache->prev_pc);
}
/* Implement the "sniffer" frame_unwind method. */
--
2.1.0