e178a5beb3
LLVM uses profiling data that's deliberately similar to GCC, but has a
very different way of exporting that data. LLVM calls llvm_gcov_init()
once per module, and provides a couple of callbacks that we can use to
ask for more data.
We care about the "writeout" callback, which in turn calls back into
compiler-rt/this module to dump all the gathered coverage data to disk:
llvm_gcda_start_file()
llvm_gcda_emit_function()
llvm_gcda_emit_arcs()
llvm_gcda_emit_function()
llvm_gcda_emit_arcs()
[... repeats for each function ...]
llvm_gcda_summary_info()
llvm_gcda_end_file()
This design is much more stateless and unstructured than gcc's, and is
intended to run at process exit. This forces us to keep some local
state about which module we're dealing with at the moment. On the other
hand, it also means we don't depend as much on how LLVM represents
profiling data internally.
See LLVM's lib/Transforms/Instrumentation/GCOVProfiling.cpp for more
details on how this works, particularly GCOVProfiler::emitProfileArcs(),
GCOVProfiler::insertCounterWriteout(), and GCOVProfiler::insertFlush().
[akpm@linux-foundation.org: coding-style fixes]
Link: http://lkml.kernel.org/r/20190417225328.208129-1-trong@android.com
Signed-off-by: Greg Hackmann <ghackmann@android.com>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Tri Vo <trong@android.com>
Co-developed-by: Nick Desaulniers <ndesaulniers@google.com>
Co-developed-by: Tri Vo <trong@android.com>
Tested-by: Trilok Soni <tsoni@quicinc.com>
Tested-by: Prasad Sodagudi <psodagud@quicinc.com>
Tested-by: Tri Vo <trong@android.com>
Tested-by: Daniel Mentz <danielmentz@google.com>
Tested-by: Petri Gynther <pgynther@google.com>
Reviewed-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
92 lines
2.8 KiB
C
92 lines
2.8 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Profiling infrastructure declarations.
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*
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* This file is based on gcc-internal definitions. Data structures are
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* defined to be compatible with gcc counterparts. For a better
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* understanding, refer to gcc source: gcc/gcov-io.h.
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*
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* Copyright IBM Corp. 2009
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* Author(s): Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
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*
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* Uses gcc-internal data definitions.
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*/
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#ifndef GCOV_H
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#define GCOV_H GCOV_H
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#include <linux/module.h>
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#include <linux/types.h>
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/*
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* Profiling data types used for gcc 3.4 and above - these are defined by
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* gcc and need to be kept as close to the original definition as possible to
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* remain compatible.
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*/
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#define GCOV_DATA_MAGIC ((unsigned int) 0x67636461)
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#define GCOV_TAG_FUNCTION ((unsigned int) 0x01000000)
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#define GCOV_TAG_COUNTER_BASE ((unsigned int) 0x01a10000)
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#define GCOV_TAG_FOR_COUNTER(count) \
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(GCOV_TAG_COUNTER_BASE + ((unsigned int) (count) << 17))
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#if BITS_PER_LONG >= 64
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typedef long gcov_type;
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#else
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typedef long long gcov_type;
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#endif
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/* Opaque gcov_info. The gcov structures can change as for example in gcc 4.7 so
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* we cannot use full definition here and they need to be placed in gcc specific
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* implementation of gcov. This also means no direct access to the members in
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* generic code and usage of the interface below.*/
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struct gcov_info;
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/* Interface to access gcov_info data */
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const char *gcov_info_filename(struct gcov_info *info);
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unsigned int gcov_info_version(struct gcov_info *info);
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struct gcov_info *gcov_info_next(struct gcov_info *info);
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void gcov_info_link(struct gcov_info *info);
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void gcov_info_unlink(struct gcov_info *prev, struct gcov_info *info);
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bool gcov_info_within_module(struct gcov_info *info, struct module *mod);
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/* Base interface. */
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enum gcov_action {
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GCOV_ADD,
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GCOV_REMOVE,
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};
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void gcov_event(enum gcov_action action, struct gcov_info *info);
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void gcov_enable_events(void);
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/* Iterator control. */
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struct seq_file;
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struct gcov_iterator;
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struct gcov_iterator *gcov_iter_new(struct gcov_info *info);
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void gcov_iter_free(struct gcov_iterator *iter);
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void gcov_iter_start(struct gcov_iterator *iter);
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int gcov_iter_next(struct gcov_iterator *iter);
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int gcov_iter_write(struct gcov_iterator *iter, struct seq_file *seq);
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struct gcov_info *gcov_iter_get_info(struct gcov_iterator *iter);
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/* gcov_info control. */
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void gcov_info_reset(struct gcov_info *info);
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int gcov_info_is_compatible(struct gcov_info *info1, struct gcov_info *info2);
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void gcov_info_add(struct gcov_info *dest, struct gcov_info *source);
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struct gcov_info *gcov_info_dup(struct gcov_info *info);
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void gcov_info_free(struct gcov_info *info);
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struct gcov_link {
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enum {
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OBJ_TREE,
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SRC_TREE,
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} dir;
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const char *ext;
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};
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extern const struct gcov_link gcov_link[];
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extern int gcov_events_enabled;
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extern struct mutex gcov_lock;
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#endif /* GCOV_H */
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