profile output path and to register a writer function. To collect profiles
without using static initializers, do this manually:
-* Export a ``int __llvm_profile_runtime`` symbol. The linker won't pull in the
- object file containing the profiling runtime's static initializer if this
- symbol is defined.
-
-* Call ``__llvm_profile_initialize_file`` once. This parses
- ``LLVM_PROFILE_FILE`` and sets the output path.
-
-* Call ``__llvm_profile_write_file`` to write out a profile.
+* Export a ``int __llvm_profile_runtime`` symbol from each instrumented shared
+ library and executable. When the linker finds a definition of this symbol, it
+ knows to skip loading the object which contains the profiling runtime's
+ static initializer.
+
+* Forward-declare ``void __llvm_profile_initialize_file(void)`` and call it
+ once from each instrumented executable. This function parses
+ ``LLVM_PROFILE_FILE``, sets the output path, and truncates any existing files
+ at that path. To get the same behavior without truncating existing files,
+ pass a filename pattern string to ``void __llvm_profile_set_filename(char
+ *)``. These calls can be placed anywhere so long as they precede all calls
+ to ``__llvm_profile_write_file``.
+
+* Forward-declare ``int __llvm_profile_write_file(void)`` and call it to write
+ out a profile. Calling this function multiple times appends profile data to
+ an existing on-disk raw profile.
Drawbacks and limitations
=========================