Date: Sat Sep 17 00:03:05 2016
New Revision: 281809
[sanitizer-coverage] change trace-pc to use 8-byte guards
--- cfe/trunk/docs/SanitizerCoverage.rst (original)
+++ cfe/trunk/docs/SanitizerCoverage.rst Sat Sep 17 00:03:05 2016
@@ -331,24 +331,23 @@ on every edge:
.. code-block:: none
- if (guard_variable != 0xff)
+ if (guard_variable >= 0)
-Every edge will have its own 1-byte `guard_variable`.
-All such guard variables will reside in a dedicated section
-(i.e. they essentially form an array).
-Similarly to `trace-pc,indirect-calls`, with `trace-pc-guards,indirect-calls`
-``__sanitizer_cov_trace_pc_indirect(void *callee)`` will be inserted on every
+Every edge will have its own 8-byte `guard_variable`.
The compler will also insert a module constructor that will call
.. code-block:: c++
- // The guard section is the address range [start, stop).
- __sanitizer_cov_trace_pc_guard_init(void *start, void *stop);
+ // The guards are [start, stop).
+ // This function may be called multiple times with the same values of
+ __sanitizer_cov_trace_pc_guard_init(uint64_t *start, uint64_t *stop);
+Similarly to `trace-pc,indirect-calls`, with `trace-pc-guards,indirect-calls`
+``__sanitizer_cov_trace_pc_indirect(void *callee)`` will be inserted on every
-The functions `__sanitizer_cov_trace_pc_guard[_init]` should be defined by the
+The functions `__sanitizer_cov_trace_pc_*` should be defined by the user.
Tracing data flow
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