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From: Victor Collod <vcollod@nvidia.com>
To: <gdb-patches@sourceware.org>
Subject: [PATCH v3 2/7] amd64_analyze_prologue: swap upper bound check condition operands
Date: Tue, 23 Jun 2020 18:28:52 -0700	[thread overview]
Message-ID: <20200624012857.31849-3-vcollod@nvidia.com> (raw)
In-Reply-To: <20200624012857.31849-1-vcollod@nvidia.com>

`if (current_pc <= pc)' felt backwards, as current_pc doesn't change,
and the test could be described as "stop if pc went past current_pc".

2020-06-23  Victor Collod  <vcollod@nvidia.com>

	* amd64-tdep.c (amd64_analyze_prologue): Swap upper bound check
	condition operands.
---
 gdb/amd64-tdep.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/gdb/amd64-tdep.c b/gdb/amd64-tdep.c
index 0ce9fbc2997..ff12cb874b8 100644
--- a/gdb/amd64-tdep.c
+++ b/gdb/amd64-tdep.c
@@ -2387,7 +2387,8 @@ amd64_analyze_prologue (struct gdbarch *gdbarch,
   gdb_byte buf[3];
   gdb_byte op;
 
-  if (current_pc <= pc)
+  /* Analysis must not go past current_pc.  */
+  if (pc >= current_pc)
     return current_pc;
 
   if (gdbarch_ptr_bit (gdbarch) == 32)
@@ -2408,7 +2409,8 @@ amd64_analyze_prologue (struct gdbarch *gdbarch,
       op = read_code_unsigned_integer (pc, 1, byte_order);
     }
 
-  if (current_pc <= pc)
+  /* If we went past the allowed bound, stop.  */
+  if (pc >= current_pc)
     return current_pc;
 
   if (op == 0x55)		/* pushq %rbp */
@@ -2418,8 +2420,8 @@ amd64_analyze_prologue (struct gdbarch *gdbarch,
       cache->saved_regs[AMD64_RBP_REGNUM] = 0;
       cache->sp_offset += 8;
 
-      /* If that's all, return now.  */
-      if (current_pc <= pc + 1)
+      /* If we went past the allowed bound, stop.  */
+      if (pc + 1 >= current_pc)
         return current_pc;
 
       read_code (pc + 1, buf, 3);
-- 
2.20.1



  parent reply	other threads:[~2020-06-24  1:29 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-05 23:23 [PATCH] Improve intel IBT support Victor Collod
2020-06-05 23:55 ` Victor Collod
2020-06-11  3:18 ` Simon Marchi
2020-06-11 22:54   ` [PATCH v2 0/2] " Victor Collod
2020-06-11 22:54     ` [PATCH v2 1/2] Add i386 support for endbr skipping Victor Collod
2020-06-21 11:27       ` Simon Marchi
2020-06-11 22:54     ` [PATCH v2 2/2] Refactor amd64_analyze_prologue Victor Collod
2020-06-21 11:38       ` Simon Marchi
2020-06-24  1:28         ` [PATCH v3 0/7] Improve intel IBT support Victor Collod
2020-06-24  1:28           ` [PATCH v3 1/7] Add i386 support for endbr skipping Victor Collod
2020-08-06 13:57             ` Simon Marchi
2020-09-19  0:29               ` [PATCH] gdb: Update i386_analyze_prologue to skip endbr32 H.J. Lu
2020-09-19  0:38                 ` Simon Marchi
2020-06-24  1:28           ` Victor Collod [this message]
2020-08-06 14:41             ` [PATCH v3 2/7] amd64_analyze_prologue: swap upper bound check condition operands Simon Marchi
2020-06-24  1:28           ` [PATCH v3 3/7] amd64_analyze_prologue: merge op and buf Victor Collod
2020-08-06 14:55             ` Simon Marchi
2020-06-24  1:28           ` [PATCH v3 4/7] amd64_analyze_prologue: invert a condition for readability Victor Collod
2020-08-06 14:57             ` Simon Marchi
2020-06-24  1:28           ` [PATCH v3 5/7] amd64_analyze_prologue: gradually update pc Victor Collod
2020-08-06 14:59             ` Simon Marchi
2020-06-24  1:28           ` [PATCH v3 6/7] amd64_analyze_prologue: fix incorrect comment Victor Collod
2020-08-06 15:05             ` Simon Marchi
2020-06-24  1:28           ` [PATCH v3 7/7] amd64_analyze_prologue: use target_read_code instead of read_code Victor Collod
2020-08-06 15:01             ` Simon Marchi
2020-08-05 21:44           ` [PATCH v3 0/7] Improve intel IBT support Victor Collod

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