[Ltrace-devel] [PATCH 2/4] Fix insertion of breakpoints on Thumb code.

[Zachary T Welch]

When a program has been built in Thumb mode, global symbols will
have their low bit set.  Ensure that breakpoints are set at the
correct address and using Thumb instructions.

Signed-off-by: Zachary T Welch <zwelch at codesourcery.com>
---
 ChangeLog     |    4 ++++
 breakpoints.c |    7 ++++++-
 2 files changed, 10 insertions(+), 1 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 0501982..d93acc2 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2010-10-07  Zach Welch <zwelch at codesourcery.com>
+
+	* Improve breakpoint insertion to work with Thumb procedures.
+
 2010-09-30  Zach Welch <zwelch at codesourcery.com>
 
 	* Improve ARM syscall_p to handle Thumb-2 syscalls.
diff --git a/breakpoints.c b/breakpoints.c
index ba3b060..ad68f0d 100644
--- a/breakpoints.c
+++ b/breakpoints.c
@@ -22,6 +22,11 @@ void
 insert_breakpoint(Process *proc, void *addr,
 		  struct library_symbol *libsym) {
 	Breakpoint *sbp;
+#ifdef __arm__
+	int thumb_mode = (int)addr & 1;
+	if (thumb_mode)
+		addr = (void *)((int)addr & ~1);
+#endif
 
 	debug(DEBUG_FUNCTION, "insert_breakpoint(pid=%d, addr=%p, symbol=%s)", proc->pid, addr, libsym ? libsym->name : "NULL");
 	debug(1, "symbol=%s, addr=%p", libsym?libsym->name:"(nil)", addr);
@@ -43,7 +48,7 @@ insert_breakpoint(Process *proc, void *addr,
 		sbp->libsym = libsym;
 	}
 #ifdef __arm__
-	sbp->thumb_mode = proc->thumb_mode;
+	sbp->thumb_mode = thumb_mode | proc->thumb_mode;
 	proc->thumb_mode = 0;
 #endif
 	sbp->enabled++;
-- 
1.7.2.2