Memento: Add Memento_tick()

Sometimes it can be useful to be able to run a program
repeatedly and stop it at a given place, just before a
problem occurs.

Suppose you know that the problem occurs in the 'foo'
function, but only after a number of runs.

Insert a call to Memento_tick() at the top of foo, rebuild
and run in the debugger. When the problem occurs, consult
memento.sequence to see what event number we are on;
suppose it's 1000.

Then you can rerun the debugger with breakpoints on Memento_inited
and Memento_breakpoint. When the program stops at Memento_inited,
call Memento_breakAt(1000) and continue execution. The program
will then stop in Memento_breakpoint within the Memento_tick
call just before the problem occurs, enabling you to step forward
and see what goes wrong.

1 files changed, 2 insertions, 0 deletions

diff --git a/base/memento.h b/base/memento.h
index 722c000ea..ec830b41f 100644
--- a/base/memento.h
+++ b/base/memento.h
@@ -214,6 +214,7 @@ void Memento_listNewBlocks(void);
 size_t Memento_setMax(size_t);
 void Memento_stats(void);
 void *Memento_label(void *, const char *);
+void Memento_tick(void);
 
 void *Memento_malloc(size_t s);
 void *Memento_realloc(void *, size_t s);
@@ -265,6 +266,7 @@ void *Memento_reference(void *blk);
 #define Memento_takeRef(A)        (A)
 #define Memento_dropRef(A)        (A)
 #define Memento_reference(A)      (A)
+#define Memento_tick()            do {} while (0)
 
 #endif /* MEMENTO */