indexed profiles. To combine profiling data from multiple runs of a program,
try e.g:
-.. code-block:: console
+ .. code-block:: console
- % llvm-profdata merge -sparse foo1.profraw foo2.profdata -o foo3.profdata
+ % llvm-profdata merge -sparse foo1.profraw foo2.profdata -o foo3.profdata
Format compatibility guarantees
===============================
* There is a third format in play: the format of the coverage mappings emitted
into instrumented binaries. Tools must retain **backwards** compatibility
with these formats. These formats are not forwards-compatible.
+
+Drawbacks and limitations
+=========================
+
+* Code coverage does not handle stack unwinding in the presence of uncaught
+ exceptions precisely. Consider the following function:
+
+ .. code-block:: cpp
+
+ int f() {
+ may_throw();
+ return 0;
+ }
+
+ If the function ``may_throw()`` propagates an exception into ``f``, the code
+ coverage tool may mark the ``return`` statement as executed even though it is
+ not.