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Re: [GOOGLE] Refactor AutoFDO


More to follow.

David

>>static void
>> read_profile (void)
>> {
>>   if (gcov_open (auto_profile_file, 1) == 0)
>>     {
>>       inform (0, "Cannot open profile file %s.", auto_profile_file);


 Should be at least warning instead -- I think error is probably more
appropriate -- this is different from regular FDO, where one missing
gcda might be ok.

>>       flag_auto_profile = 0;
>>       return;
>>     }
>>
>>   if (gcov_read_unsigned () != GCOV_DATA_MAGIC)
>>     {
>>       inform (0, "Magic number does not mathch.");

Should be an error.

>>       flag_auto_profile = 0;
>>       return;
>>     }
>>
>>
>>   /* function_name_map.  */
>>   afdo_function_name_map = function_name_map::create ();
>>   if (afdo_function_name_map == NULL)
>>     {
>>       inform (0, "Cannot read string table.");

Should be an error unless there is a way to recover. Falling back to
non-fdo is not the solution.

>>       flag_auto_profile = 0;
>>       return;
>>     }
>>
>>   /* autofdo_source_profile.  */
>>   afdo_source_profile = autofdo_source_profile::create ();
>>   if (afdo_source_profile == NULL)
>>     {
>>       inform (0, "Cannot read function profile.");

An error.

>>       flag_auto_profile = 0;
>>       return;
>>     }
>>
>>   /* autofdo_module_profile.  */
>>   afdo_module_profile = autofdo_module_profile::create ();
>>   if (afdo_module_profile == NULL)
>>     {
>>       inform (0, "Cannot read module profile.");

Should be an error.

>>       flag_auto_profile = 0;
>>       return;
>>     }
>>
>>   /* Read in the working set.  */
>>   if (gcov_read_unsigned () != GCOV_TAG_AFDO_WORKING_SET)
>>     {
>>       inform (0, "Not expected TAG.");

Error.

>>   unsigned curr_module = 1, max_group = PARAM_VALUE (PARAM_MAX_LIPO_GROUP);
>>   for (string_vector::const_iterator iter = aux_modules->begin();
>>        iter != aux_modules->end(); ++iter)
>>     {
>>       gcov_module_info *aux_module = afdo_module_profile->get_module (*iter);
>>       if (aux_module == module)
>> continue;
>>       if (aux_module == NULL)
>> {
>>  inform (0, "aux module %s cannot be found.", *iter);
>>  continue;
>> }
>>       if ((aux_module->lang & GCOV_MODULE_LANG_MASK) !=
>>  (module->lang & GCOV_MODULE_LANG_MASK))
>> {
>>  inform (0, "Not importing %s: source language"
>>  " different from primary module's source language", *iter);


Should be guarded with -fopt-info -- see similar code in coverage.c.

>>  continue;
>> }
>>       if ((aux_module->lang & GCOV_MODULE_ASM_STMTS)
>>   && flag_ripa_disallow_asm_modules)
>> {
>>  if (flag_opt_info)
>>    inform (0, "Not importing %s: contains "
>>    "assembler statements", *iter);

Use -fopt-info

>>  continue;
>> }
>>       if (max_group != 0 && curr_module == max_group)
>> {
>>  if (flag_opt_info)
>>    inform (0, "Not importing %s: maximum group size reached", *iter);
>> }
>>       if (incompatible_cl_args (module, aux_module))
>> {
>>  if (flag_opt_info)
>>    inform (0, "Not importing %s: command-line"
>>    " arguments not compatible with primary module", *iter);
>>  continue;

Use -fopt-info.


>> }
>>       module_infos[curr_module++] = aux_module;
>>       add_input_filename (*iter);
>>     }
>> }
>>
>> /* From AutoFDO profiles, find values inside STMT for that we want to measure
>>    histograms for indirect-call optimization.  */
>>
>>     {
>>       hist->hvalue.counters[3] = 0;
>>       hist->hvalue.counters[4] = 0;
>>     }

It might be better to create a commmon API to create/update histogram
entry instead of peeking into the details of the data structure -- to
avoid future breaks. Such a change can be done as a follow up and
needs to be in trunk.

>> }
>>
>> /* From AutoFDO profiles, find values inside STMT for that we want to measure
>>    histograms and adds them to list VALUES.  */
>>
>> static void
>> afdo_vpt (gimple stmt, const icall_target_map &map)
>> {
>>   afdo_indirect_call (stmt, map);
>> }
>>
>> /* For a given BB, return its execution count, and annotate value profile
>>    on statements.  */
>>
>> static gcov_type
>> afdo_get_bb_count (basic_block bb)
>> {
>>   gimple_stmt_iterator gsi;
>>   gcov_type max_count = 0;
>>   bool has_annotated = false;
>>
>>   for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
>>     {
>>       count_info info;
>>       gimple stmt = gsi_stmt (gsi);
>>       if (afdo_source_profile->get_count_info (stmt, &info))
>> {

indentation.

>>  if (info.first > max_count)
>>    max_count = info.first;
>>  has_annotated = true;
>>  if (info.second.size() > 0)
>>    afdo_vpt (stmt, info.second);
>> }
>>     }
>>   if (has_annotated)
>>     {
>>       bb->flags |= BB_ANNOTATED;
>>       return max_count;
>>     }
>>   else
>>     return 0;
>> }
>>
>>
>> static void
>> afdo_annotate_cfg (void)
>> {
>>   basic_block bb;
>>   const function_instance *s =
>>       afdo_source_profile->get_function_instance_by_decl (
>>       current_function_decl);

need a new line after decls.

On Thu, Aug 1, 2013 at 2:49 PM, Dehao Chen <dehao@google.com> wrote:
> On Wed, Jul 31, 2013 at 10:14 AM, Xinliang David Li <davidxl@google.com> wrote:
>> Another round of documentation  and naming (not for coding style, but
>> for clearer semantics) related comments:
>>
>> David
>>
>>>
>>> namespace autofdo {
>>>
>>> /* Represent a source location: (function_decl, lineno).  */
>>> typedef std::pair<tree, unsigned> decl_lineno;
>>> /* Represent an inline stack. vector[0] is the leaf node.  */
>>> typedef std::vector<decl_lineno> inline_stack;
>>
>> leaf or root?
>
> leaf
>
>>
>>> /* String array.  */
>>> typedef std::vector<const char *> string_vector;
>>
>> Module name, function name strings or a generic string table??
>
> done
>>
>>> /* Map from index in string_map to profile count.  */
>>> typedef std::map<unsigned, gcov_type> target_map;
>>
>> What index? function index?  Is profile count function profile count
>> or target call count?
>
> done
>>
>> Should it renamed to icall_target_map to be clearer?
>
> done
>>
>>> /* Represent profile count: (execution_count, value_profile_histogram.  */
>>> typedef std::pair<gcov_type, target_map> count_info;
>>>
>>
>> The executation count is for what entity?
>
> done
>>
>>> struct string_compare
>>> {
>>>   bool operator() (const char *a, const char *b) const
>>>     { return strcmp (a, b) < 0; }
>>> };
>>>
>>> /* Store a string array, indexed by string position in the array.  */
>>> class string_map {
>>
>> Is it better to rename it to function_name_map ? string_map is too general.
>
> done
>>
>>
>>>  public:
>>>   static string_map *create ();
>>>
>>>   /* For a given string, returns its index.  */
>>>   int get_index (const char *name) const;
>>>   /* For a given decl, returns the index of the decl name.  */
>>>   int get_index_by_decl (tree decl) const;
>>>   /* For a given index, returns the string.  */
>>>   const char *get_name (int index) const;
>>>
>>>  private:
>>>   string_map () {}
>>>   bool read ();
>>>
>>>   typedef std::map<const char *, unsigned, string_compare> string_index_map;
>>>   string_vector vector_;
>>>   string_index_map map_;
>>> };
>>>
>>> /* Profile of a function copy:
>>>      1. total_count of the copy.
>>>      2. head_count of the copy (only valid when the copy is a top-level
>>> symbol, i.e. it is the original copy instead of the inlined copy).
>>>      3. map from source location (decl_lineno) to profile (count_info).
>>
>> Source location of the inlined callsite?
>
> done
>>
>>>      4. map from callsite (64 bit integer, higher 32 bit is source location
>>> (decl_lineno), lower 32 bit is callee function name index in
>>> string_map) to callee symbol.  */
>>> class symbol {
>>
>>
>> May be rename it to " function_instance" ?
>
> done
>>
>>> public:
>>>   typedef std::vector<symbol *> symbol_stack;
>>>
>>>   /* Read the profile and create a symbol with head count as  HEAD_COUNT.
>>>      Recursively read callsites to create nested symbols too. STACK is used
>>>      to track the recursive creation process.  */
>>>   static const symbol *read_symbol (symbol_stack *stack, gcov_type head_count);
>>>
>>>   /* Recursively deallocate all callsites (nested symbols).  */
>>>   ~symbol ();
>>>
>>>   /* Accessors.  */
>>>   unsigned name () const { return name_; }
>>>   gcov_type total_count () const { return total_count_; }
>>>   gcov_type head_count () const { return head_count_; }
>>>
>>>   /* Recursively traverse STACK starting from LEVEL to find the corresponding
>>>      symbol.  */
>>>   const symbol *get_symbol (const inline_stack &stack, unsigned level) const;
>>>
>>>   /* Return the profile info for LOC.  */
>>>   bool get_count_info (location_t loc, count_info *info) const;
>>>
>>> private:
>>>   symbol (unsigned name, gcov_type head_count)
>>>       : name_(name), total_count_(0), head_count_(head_count) {}
>>>   const symbol *get_symbol_by_decl (unsigned lineno, tree decl) const;
>>>
>>>   /* Map from callsite (64 bit integer, higher 32 bit is source location
>>>      (decl_lineno), lower 32 bit is callee function name index in
>>>      string_map) to callee symbol.  */
>>>   typedef std::map<gcov_type, const symbol *> callsite_map;
>>
>> Why not making a pair and use it as the key?
>
> done
>>
>>>   /* Map from source location (decl_lineno) to profile (count_info).  */
>>>   typedef std::map<unsigned, count_info> position_count_map;
>>>
>>>   /* symbol name index in the string map.  */
>>
>>
>> Index in string_vector or string_map?
>
> done
>>
>>>   unsigned name_;
>>>   /* The total sampled count.  */
>>>   gcov_type total_count_;
>>>   /* The total sampled count in the head bb.  */
>>>   gcov_type head_count_;
>>>   /* Map from callsite location to callee symbol.  */
>>>   callsite_map callsites;
>>>   /* Map from source location to count and instruction number.  */
>>>   position_count_map pos_counts;
>>> };
>>>
>>> /* Profile for all functions.  */
>>> class symbol_map {
>>
>>
>> symbol_map --> program_profiles or afdo_profile ?
>
> done
>>
>>> public:
>>>   static symbol_map *create ()
>>>     {
>>>       symbol_map *map = new symbol_map ();
>>>       if (map->read ())
>>> return map;
>>>       delete map;
>>>       return NULL;
>>>     }
>>>   ~symbol_map ();
>>>   /* For a given DECL, returns the top-level symbol.  */
>>>   const symbol *get_symbol_by_decl (tree decl) const;
>>>   /* Find profile info for a given gimple STMT. If found, store the profile
>>>      info in INFO, and return true; otherwise return false.  */
>>>   bool get_count_info (gimple stmt, count_info *info) const;
>>>   /* Find total count of the callee of EDGE.  */
>>>   gcov_type get_callsite_total_count (struct cgraph_edge *edge) const;
>>>
>>> private:
>>>   /* Map from symbol name index (in string_map) to symbol.  */
>>>   typedef std::map<unsigned, const symbol *> Namesymbol_map;
>>>
>>>   symbol_map () {}
>>>   bool read ();
>>>   /* Return the symbol in the profile that correspond to the inline STACK.  */
>>>   const symbol *get_symbol_by_inline_stack (const inline_stack &stack) const;
>>>
>>>   Namesymbol_map map_;
>>> };
>>>
>>> /* Module profile.  */
>>> class module_map {
>>
>> afdo_module_profile ?
>
> done
>>
>>> public:
>>>   static module_map *create ()
>>>     {
>>>       module_map *map = new module_map ();
>>>       if (map->read ())
>>> return map;
>>>       delete map;
>>>       return NULL;
>>>     }
>>>
>>>   /* For a given module NAME, returns this module's gcov_m
>>
>> On Tue, Jul 30, 2013 at 4:48 PM, Dehao Chen <dehao@google.com> wrote:
>>> Patch updated to fix the code style and documentation.
>>>
>>> Thanks,
>>> Dehao
>>>
>>> On Tue, Jul 30, 2013 at 2:24 PM, Xinliang David Li <davidxl@google.com> wrote:
>>>> I have some preliminary comments. Mostly just related to code style
>>>> and missing documentation.
>>>>
>>>> David
>>>>
>>>>>
>>>>> #define DEFAULT_AUTO_PROFILE_FILE "fbdata.afdo"
>>>>>
>>>>> struct SourceLocation
>>>>
>>>> Is using Upper case in struct names allowed?
>>>>
>>>>> {
>>>>>   tree func_decl;
>>>>>   unsigned lineno;
>>>>> };
>>>>>
>>>>> typedef std::vector<const char *> StringVector;
>>>>> typedef std::vector<SourceLocation> InlineStack;
>>>>> typedef std::map<unsigned, gcov_type> TargetMap;
>>>>>
>>>>
>>>> Add short description of each new types.
>>>>
>>>>> struct ProfileInfo
>>>>> {
>>>>>   gcov_type count;
>>>>>   TargetMap target_map;
>>>>> };
>>>>>
>>>>> struct StringCompare
>>>>> {
>>>>>   bool operator() (const char* a, const char* b) const
>>>>
>>>> '*' should bind to name.
>>>>
>>>>>     { return strcmp (a, b) < 0; }
>>>>> };
>>>>>
>>>>
>>>>> class StringMap {
>>>>>  public:
>>>>>   static StringMap *Create();
>>>>>   int GetIndex (const char *name) const;
>>>>>   int GetIndexByDecl (tree decl) const;
>>>>>   const char *GetName (int index) const;
>>>>>
>>>>>  private:
>>>>>   StringMap () {}
>>>>>   bool Read ();
>>>>>
>>>>>   typedef std::map<const char *, unsigned, StringCompare> StringIndexMap;
>>>>>   StringVector vector_;
>>>>>   StringIndexMap map_;
>>>>> };
>>>>
>>>> Add some documentation on the new type, indicating what is 'index'.
>>>>
>>>>>
>>>>> class Symbol {
>>>>
>>>> The name 'Symbol' is too generic -- can cause conflicts in the future
>>>> unless namespace is used. ALso missing documentation.
>>>>
>>>>>  public:
>>>>>   typedef std::vector<Symbol *> SymbolStack;
>>>>
>>>> Fix indentation problems.
>>>>
>>>>
>>>>>
>>>>>   /* Read the profile and create a symbol with head count as  HEAD_COUNT.
>>>>>      Recursively read callsites to create nested symbols too. STACK is used
>>>>>      to track the recursive creation process.  */
>>>>>   static const Symbol *ReadSymbol (SymbolStack *stack, gcov_type head_count);
>>>>>
>>>>>   /* Recursively deallocate all callsites (nested symbols).  */
>>>>>   ~Symbol ();
>>>>>
>>>>>   /* Accessors.  */
>>>>>   unsigned name () const { return name_; }
>>>>>   gcov_type total_count () const { return total_count_; }
>>>>>   gcov_type head_count () const { return head_count_; }
>>>>>
>>>>>   /* Recursively traverse STACK starting from LEVEL to find the corresponding
>>>>>      symbol.  */
>>>>>   const Symbol *GetSymbol (const InlineStack &stack, unsigned level) const;
>>>>>
>>>>>   /* Return the profile info for LOC.  */
>>>>>   bool GetProfileInfo (location_t loc, ProfileInfo *info) const;
>>>>>
>>>>>  private:
>>>>>   Symbol (unsigned name, gcov_type head_count)
>>>>>       : name_(name), total_count_(0), head_count_(head_count) {}
>>>>>   const Symbol *GetSymbolByDecl (unsigned lineno, tree decl) const;
>>>>>
>>>>>   typedef std::map<gcov_type, const Symbol *> CallsiteMap;
>>>>
>>>> Need documentation for this map.
>>>>
>>>>>   typedef std::map<unsigned, ProfileInfo> PositionCountMap;
>>>>
>>>> Need documentation.
>>>>
>>>>>
>>>>>   /* Symbol name index in the string map.  */
>>>>>   unsigned name_;
>>>>>   /* The total sampled count.  */
>>>>>   gcov_type total_count_;
>>>>>   /* The total sampled count in the head bb.  */
>>>>>   gcov_type head_count_;
>>>>>   /* Map from callsite location to callee symbol.  */
>>>>>   CallsiteMap callsites;
>>>>>   /* Map from source location to count and instruction number.  */
>>>>>   PositionCountMap pos_counts;
>>>>> };
>>>>>
>>>>> class SymbolMap {
>>>>
>>>> Need documentation.
>>>>
>>>>>  public:
>>>>>   static SymbolMap *Create ()
>>>>>     {
>>>>>       SymbolMap *map = new SymbolMap ();
>>>>>       if (map->Read ())
>>>>> return map;
>>>>>       delete map;
>>>>>       return NULL;
>>>>>     }
>>>>>   ~SymbolMap ();
>>>>>   const Symbol *GetSymbolByDecl (tree decl) const;
>>>>>   bool GetProfileInfo (gimple stmt, ProfileInfo *info) const;
>>>>>   gcov_type GetCallsiteTotalCount (struct cgraph_edge *edge) const;
>>>>
>>>>  Missing documentation for the interfaces
>>>>>
>>>>>  private:
>>>>
>>>>>   typedef std::map<unsigned, const Symbol *> NameSymbolMap;
>>>>
>>>> map from what to symbol?
>>>>
>>>>>
>>>>>   SymbolMap () {}
>>>>>   bool Read ();
>>>>>   const Symbol *GetSymbolByInlineStack (const InlineStack &stack) const;
>>>>
>>>>  Missing documentation for the interfaces
>>>>
>>>>
>>>>>
>>>>>   NameSymbolMap map_;
>>>>> };
>>>>>
>>>>> class ModuleMap {
>>>>
>>>> Need documentation.
>>>>
>>>> On Tue, Jul 30, 2013 at 11:03 AM, Dehao Chen <dehao@google.com> wrote:
>>>>> I just rebased the CL to head and updated the patch.
>>>>>
>>>>> Thanks,
>>>>> Dehao
>>>>>
>>>>> On Tue, Jul 30, 2013 at 10:09 AM, Xinliang David Li <davidxl@google.com> wrote:
>>>>>> I can not apply the patch cleanly in my v17 gcc client -- there is
>>>>>> some problem in auto-profile.c.
>>>>>>
>>>>>> David
>>>>>>
>>>>>> On Mon, Jul 29, 2013 at 7:52 PM, Dehao Chen <dehao@google.com> wrote:
>>>>>>> This patch refactors AutoFDO to use:
>>>>>>>
>>>>>>> 1. C++ to rewrite the whole thing.
>>>>>>> 2. Use tree instead of hashtable to represent the profile.
>>>>>>> 3. Make AutoFDO standalone: keep changes to other modules minimum.
>>>>>>>
>>>>>>> Bootstrapped and passed regression test and benchmark test.
>>>>>>>
>>>>>>> OK for google-4_8 branch?
>>>>>>>
>>>>>>> Thanks,
>>>>>>> Dehao
>>>>>>>
>>>>>>> http://codereview.appspot.com/12079043


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