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	The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array
member[1][2], introduced in C99:
struct foo {
        int stuff;
        struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning in
case the flexible array does not occur last in the structure, which will
help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.
Also, notice that, dynamic memory allocations won't be affected by this
change:
"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]
sizeof(flexible-array-member) triggers a warning because flexible array
members have incomplete type[1]. There are some instances of code in
which the sizeof operator is being incorrectly/erroneously applied to
zero-length arrays and the result is zero. Such instances may be hiding
some bugs. So, this work (flexible-array member conversions) will also
help to get completely rid of those sorts of issues.
This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Gustavo A. R. Silva <gustavo@embeddedor.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20200515172926.GA31976@embeddedor
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
		
	
			
		
			
				
	
	
		
			420 lines
		
	
	
	
		
			11 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			420 lines
		
	
	
	
		
			11 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __PERF_ANNOTATE_H
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#define __PERF_ANNOTATE_H
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#include <stdbool.h>
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#include <stdint.h>
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#include <stdio.h>
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#include <linux/types.h>
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#include <linux/list.h>
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#include <linux/rbtree.h>
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#include <pthread.h>
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#include <asm/bug.h>
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#include "symbol_conf.h"
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#include "spark.h"
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struct hist_browser_timer;
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struct hist_entry;
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struct ins_ops;
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struct map;
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struct map_symbol;
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struct addr_map_symbol;
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struct option;
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struct perf_sample;
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struct evsel;
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struct symbol;
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struct ins {
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	const char     *name;
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	struct ins_ops *ops;
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};
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struct ins_operands {
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	char	*raw;
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	char	*raw_comment;
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	struct {
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		char	*raw;
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		char	*name;
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		struct symbol *sym;
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		u64	addr;
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		s64	offset;
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		bool	offset_avail;
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		bool	outside;
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	} target;
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	union {
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		struct {
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			char	*raw;
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			char	*name;
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			u64	addr;
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		} source;
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		struct {
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			struct ins	    ins;
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			struct ins_operands *ops;
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		} locked;
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	};
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};
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struct arch;
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struct ins_ops {
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	void (*free)(struct ins_operands *ops);
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	int (*parse)(struct arch *arch, struct ins_operands *ops, struct map_symbol *ms);
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	int (*scnprintf)(struct ins *ins, char *bf, size_t size,
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			 struct ins_operands *ops, int max_ins_name);
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};
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bool ins__is_jump(const struct ins *ins);
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bool ins__is_call(const struct ins *ins);
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bool ins__is_ret(const struct ins *ins);
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bool ins__is_lock(const struct ins *ins);
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int ins__scnprintf(struct ins *ins, char *bf, size_t size, struct ins_operands *ops, int max_ins_name);
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bool ins__is_fused(struct arch *arch, const char *ins1, const char *ins2);
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#define ANNOTATION__IPC_WIDTH 6
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#define ANNOTATION__CYCLES_WIDTH 6
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#define ANNOTATION__MINMAX_CYCLES_WIDTH 19
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#define ANNOTATION__AVG_IPC_WIDTH 36
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#define ANNOTATION_DUMMY_LEN	256
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struct annotation_options {
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	bool hide_src_code,
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	     use_offset,
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	     jump_arrows,
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	     print_lines,
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	     full_path,
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	     show_linenr,
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	     show_nr_jumps,
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	     show_minmax_cycle,
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	     show_asm_raw,
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	     annotate_src;
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	u8   offset_level;
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	int  min_pcnt;
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	int  max_lines;
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	int  context;
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	const char *objdump_path;
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	const char *disassembler_style;
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	const char *prefix;
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	const char *prefix_strip;
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	unsigned int percent_type;
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};
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enum {
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	ANNOTATION__OFFSET_JUMP_TARGETS = 1,
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	ANNOTATION__OFFSET_CALL,
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	ANNOTATION__MAX_OFFSET_LEVEL,
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};
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#define ANNOTATION__MIN_OFFSET_LEVEL ANNOTATION__OFFSET_JUMP_TARGETS
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extern struct annotation_options annotation__default_options;
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struct annotation;
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struct sym_hist_entry {
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	u64		nr_samples;
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	u64		period;
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};
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enum {
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	PERCENT_HITS_LOCAL,
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	PERCENT_HITS_GLOBAL,
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	PERCENT_PERIOD_LOCAL,
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	PERCENT_PERIOD_GLOBAL,
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	PERCENT_MAX,
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};
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struct annotation_data {
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	double			 percent[PERCENT_MAX];
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	double			 percent_sum;
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	struct sym_hist_entry	 he;
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};
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struct annotation_line {
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	struct list_head	 node;
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	struct rb_node		 rb_node;
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	s64			 offset;
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	char			*line;
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	int			 line_nr;
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	int			 jump_sources;
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	float			 ipc;
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	u64			 cycles;
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	u64			 cycles_max;
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	u64			 cycles_min;
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	char			*path;
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	u32			 idx;
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	int			 idx_asm;
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	int			 data_nr;
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	struct annotation_data	 data[];
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};
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struct disasm_line {
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	struct ins		 ins;
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	struct ins_operands	 ops;
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	/* This needs to be at the end. */
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	struct annotation_line	 al;
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};
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static inline double annotation_data__percent(struct annotation_data *data,
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					      unsigned int which)
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{
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	return which < PERCENT_MAX ? data->percent[which] : -1;
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}
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static inline const char *percent_type_str(unsigned int type)
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{
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	static const char *str[PERCENT_MAX] = {
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		"local hits",
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		"global hits",
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		"local period",
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		"global period",
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	};
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	if (WARN_ON(type >= PERCENT_MAX))
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		return "N/A";
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	return str[type];
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}
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static inline struct disasm_line *disasm_line(struct annotation_line *al)
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{
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	return al ? container_of(al, struct disasm_line, al) : NULL;
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}
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/*
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 * Is this offset in the same function as the line it is used?
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 * asm functions jump to other functions, for instance.
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 */
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static inline bool disasm_line__has_local_offset(const struct disasm_line *dl)
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{
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	return dl->ops.target.offset_avail && !dl->ops.target.outside;
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}
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/*
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 * Can we draw an arrow from the jump to its target, for instance? I.e.
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 * is the jump and its target in the same function?
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 */
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bool disasm_line__is_valid_local_jump(struct disasm_line *dl, struct symbol *sym);
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void disasm_line__free(struct disasm_line *dl);
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struct annotation_line *
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annotation_line__next(struct annotation_line *pos, struct list_head *head);
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struct annotation_write_ops {
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	bool first_line, current_entry, change_color;
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	int  width;
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	void *obj;
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	int  (*set_color)(void *obj, int color);
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	void (*set_percent_color)(void *obj, double percent, bool current);
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	int  (*set_jumps_percent_color)(void *obj, int nr, bool current);
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	void (*printf)(void *obj, const char *fmt, ...);
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	void (*write_graph)(void *obj, int graph);
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};
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void annotation_line__write(struct annotation_line *al, struct annotation *notes,
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			    struct annotation_write_ops *ops,
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			    struct annotation_options *opts);
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int __annotation__scnprintf_samples_period(struct annotation *notes,
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					   char *bf, size_t size,
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					   struct evsel *evsel,
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					   bool show_freq);
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int disasm_line__scnprintf(struct disasm_line *dl, char *bf, size_t size, bool raw, int max_ins_name);
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size_t disasm__fprintf(struct list_head *head, FILE *fp);
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void symbol__calc_percent(struct symbol *sym, struct evsel *evsel);
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struct sym_hist {
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	u64		      nr_samples;
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	u64		      period;
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	struct sym_hist_entry addr[];
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};
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struct cyc_hist {
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	u64	start;
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	u64	cycles;
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	u64	cycles_aggr;
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	u64	cycles_max;
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	u64	cycles_min;
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	s64	cycles_spark[NUM_SPARKS];
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	u32	num;
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	u32	num_aggr;
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	u8	have_start;
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	/* 1 byte padding */
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	u16	reset;
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};
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/** struct annotated_source - symbols with hits have this attached as in sannotation
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 *
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 * @histograms: Array of addr hit histograms per event being monitored
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 * nr_histograms: This may not be the same as evsel->evlist->core.nr_entries if
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 * 		  we have more than a group in a evlist, where we will want
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 * 		  to see each group separately, that is why symbol__annotate2()
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 * 		  sets src->nr_histograms to evsel->nr_members.
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 * @lines: If 'print_lines' is specified, per source code line percentages
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 * @source: source parsed from a disassembler like objdump -dS
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 * @cyc_hist: Average cycles per basic block
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 *
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 * lines is allocated, percentages calculated and all sorted by percentage
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 * when the annotation is about to be presented, so the percentages are for
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 * one of the entries in the histogram array, i.e. for the event/counter being
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 * presented. It is deallocated right after symbol__{tui,tty,etc}_annotate
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 * returns.
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 */
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struct annotated_source {
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	struct list_head   source;
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	int    		   nr_histograms;
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	size_t		   sizeof_sym_hist;
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	struct cyc_hist	   *cycles_hist;
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	struct sym_hist	   *histograms;
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};
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struct annotation {
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	pthread_mutex_t		lock;
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	u64			max_coverage;
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	u64			start;
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	u64			hit_cycles;
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	u64			hit_insn;
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	unsigned int		total_insn;
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	unsigned int		cover_insn;
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	struct annotation_options *options;
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	struct annotation_line	**offsets;
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	int			nr_events;
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	int			max_jump_sources;
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	int			nr_entries;
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	int			nr_asm_entries;
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	u16			max_line_len;
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	struct {
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		u8		addr;
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		u8		jumps;
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		u8		target;
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		u8		min_addr;
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		u8		max_addr;
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		u8		max_ins_name;
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	} widths;
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	bool			have_cycles;
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	struct annotated_source *src;
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};
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static inline int annotation__cycles_width(struct annotation *notes)
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{
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	if (notes->have_cycles && notes->options->show_minmax_cycle)
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		return ANNOTATION__IPC_WIDTH + ANNOTATION__MINMAX_CYCLES_WIDTH;
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	return notes->have_cycles ? ANNOTATION__IPC_WIDTH + ANNOTATION__CYCLES_WIDTH : 0;
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}
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static inline int annotation__pcnt_width(struct annotation *notes)
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{
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	return (symbol_conf.show_total_period ? 12 : 7) * notes->nr_events;
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}
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static inline bool annotation_line__filter(struct annotation_line *al, struct annotation *notes)
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{
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	return notes->options->hide_src_code && al->offset == -1;
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}
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void annotation__set_offsets(struct annotation *notes, s64 size);
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void annotation__compute_ipc(struct annotation *notes, size_t size);
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void annotation__mark_jump_targets(struct annotation *notes, struct symbol *sym);
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void annotation__update_column_widths(struct annotation *notes);
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void annotation__init_column_widths(struct annotation *notes, struct symbol *sym);
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static inline struct sym_hist *annotated_source__histogram(struct annotated_source *src, int idx)
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{
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	return ((void *)src->histograms) + (src->sizeof_sym_hist * idx);
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}
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static inline struct sym_hist *annotation__histogram(struct annotation *notes, int idx)
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{
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	return annotated_source__histogram(notes->src, idx);
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}
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static inline struct annotation *symbol__annotation(struct symbol *sym)
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{
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	return (void *)sym - symbol_conf.priv_size;
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}
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int addr_map_symbol__inc_samples(struct addr_map_symbol *ams, struct perf_sample *sample,
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				 struct evsel *evsel);
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int addr_map_symbol__account_cycles(struct addr_map_symbol *ams,
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				    struct addr_map_symbol *start,
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				    unsigned cycles);
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int hist_entry__inc_addr_samples(struct hist_entry *he, struct perf_sample *sample,
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				 struct evsel *evsel, u64 addr);
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struct annotated_source *symbol__hists(struct symbol *sym, int nr_hists);
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void symbol__annotate_zero_histograms(struct symbol *sym);
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int symbol__annotate(struct map_symbol *ms,
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		     struct evsel *evsel,
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		     struct annotation_options *options,
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		     struct arch **parch);
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int symbol__annotate2(struct map_symbol *ms,
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		      struct evsel *evsel,
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		      struct annotation_options *options,
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		      struct arch **parch);
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enum symbol_disassemble_errno {
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	SYMBOL_ANNOTATE_ERRNO__SUCCESS		= 0,
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	/*
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	 * Choose an arbitrary negative big number not to clash with standard
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	 * errno since SUS requires the errno has distinct positive values.
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	 * See 'Issue 6' in the link below.
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	 *
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	 * http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/errno.h.html
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	 */
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	__SYMBOL_ANNOTATE_ERRNO__START		= -10000,
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	SYMBOL_ANNOTATE_ERRNO__NO_VMLINUX	= __SYMBOL_ANNOTATE_ERRNO__START,
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	SYMBOL_ANNOTATE_ERRNO__NO_LIBOPCODES_FOR_BPF,
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	SYMBOL_ANNOTATE_ERRNO__ARCH_INIT_CPUID_PARSING,
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	SYMBOL_ANNOTATE_ERRNO__ARCH_INIT_REGEXP,
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	SYMBOL_ANNOTATE_ERRNO__BPF_INVALID_FILE,
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	SYMBOL_ANNOTATE_ERRNO__BPF_MISSING_BTF,
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	__SYMBOL_ANNOTATE_ERRNO__END,
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};
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int symbol__strerror_disassemble(struct map_symbol *ms, int errnum, char *buf, size_t buflen);
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int symbol__annotate_printf(struct map_symbol *ms, struct evsel *evsel,
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			    struct annotation_options *options);
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void symbol__annotate_zero_histogram(struct symbol *sym, int evidx);
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void symbol__annotate_decay_histogram(struct symbol *sym, int evidx);
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void annotated_source__purge(struct annotated_source *as);
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int map_symbol__annotation_dump(struct map_symbol *ms, struct evsel *evsel,
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				struct annotation_options *opts);
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bool ui__has_annotation(void);
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int symbol__tty_annotate(struct map_symbol *ms, struct evsel *evsel, struct annotation_options *opts);
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int symbol__tty_annotate2(struct map_symbol *ms, struct evsel *evsel, struct annotation_options *opts);
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#ifdef HAVE_SLANG_SUPPORT
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int symbol__tui_annotate(struct map_symbol *ms, struct evsel *evsel,
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			 struct hist_browser_timer *hbt,
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			 struct annotation_options *opts);
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#else
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static inline int symbol__tui_annotate(struct map_symbol *ms __maybe_unused,
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				struct evsel *evsel  __maybe_unused,
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						|
				struct hist_browser_timer *hbt __maybe_unused,
 | 
						|
				struct annotation_options *opts __maybe_unused)
 | 
						|
{
 | 
						|
	return 0;
 | 
						|
}
 | 
						|
#endif
 | 
						|
 | 
						|
void annotation_config__init(struct annotation_options *opt);
 | 
						|
 | 
						|
int annotate_parse_percent_type(const struct option *opt, const char *_str,
 | 
						|
				int unset);
 | 
						|
 | 
						|
int annotate_check_args(struct annotation_options *args);
 | 
						|
 | 
						|
#endif	/* __PERF_ANNOTATE_H */
 |