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Re: [PATCH] Come up with json::integer_number and use it in GCOV.


On 7/31/19 3:13 PM, David Malcolm wrote:
> On Wed, 2019-07-31 at 10:42 +0200, Martin Liška wrote:
>> Hi.
>>
>> As seen here:
>> https://github.com/RPGillespie6/fastcov/pull/18/files/f184dd8b6fc14e0
>> 75dfc0ea93de7be5c96298ddb#r308735088
>>
>> GCOV uses json::number for branch count, line count and similar.
>> However, the json library
>> uses a double as an internal representation for numbers. That's no
>> desirable in case
>> of GCOV and so that I would like to come up with integer_number type.
>> David would you be fine with that?
> 
> Thanks for the patch; overall I'm broadly in favor of the idea, but I
> think the patch needs a little work.
> 
> The JSON standard has a definition for numbers that allows for both
> integers and floats, and says this about interoperability:
>  
> https://tools.ietf.org/html/rfc7159#section-6
> https://tools.ietf.org/html/rfc8259#section-6
> 
> "This specification allows implementations to set limits on the range
>    and precision of numbers accepted.  Since software that implements
>    IEEE 754 binary64 (double precision) numbers [IEEE754] is generally
>    available and widely used, good interoperability can be achieved by
>    implementations that expect no more precision or range than these
>    provide, in the sense that implementations will approximate JSON
>    numbers within the expected precision."
> 
> Hence I chose "double" as the representation.  But, yeah, it's a pain
> when dealing with large integers.
> 
> [see also "Parsing JSON is a Minefield"
>   http://seriot.ch/parsing_json.php#22 ]
> 
> Looking at your patch, you convert some places to integer_number, and
> some to float_number.
> 
> It looks to me like you converted the gcov places you were concerned
> about to integer, and kept the "status quo" as floats for the other
> ones.  But in all of the places I can see, I think integers make more
> sense than floats.

Yep, but you are right that all other places also needed integer_type :)

> 
> I think we want to preserve the capability to emit floating point json
> values, but I suspect we want to use integer values everywhere we're
> currently emitting json; it's probably worth going through them line by
> line...

I'm fine with preservation of the type.

> 
>> diff --git a/gcc/diagnostic-format-json.cc b/gcc/diagnostic-format-json.cc
>> index 53c3b630b1c..2802da8a0a6 100644
>> --- a/gcc/diagnostic-format-json.cc
>> +++ b/gcc/diagnostic-format-json.cc
>> @@ -48,8 +48,8 @@ json_from_expanded_location (location_t loc)
>>    json::object *result = new json::object ();
>>    if (exploc.file)
>>      result->set ("file", new json::string (exploc.file));
>> -  result->set ("line", new json::number (exploc.line));
>> -  result->set ("column", new json::number (exploc.column));
>> +  result->set ("line", new json::float_number (exploc.line));
>> +  result->set ("column", new json::float_number (exploc.column));
> 
> These should be integers.
> 
> 
> [...snip gcov hunks...]
> 
>> diff --git a/gcc/json.cc b/gcc/json.cc
>> index 512e2e513b9..bec6fc53cc8 100644
>> --- a/gcc/json.cc
>> +++ b/gcc/json.cc
>> @@ -154,18 +154,31 @@ array::append (value *v)
>>    m_elements.safe_push (v);
>>  }
>>  
>> -/* class json::number, a subclass of json::value, wrapping a double.  */
>> +/* class json::float_number, a subclass of json::value, wrapping a double.  */
> 
> Would it make more sense to call this "double_number"?  (am not sure)

I would prefer to stay with json::float_number.

> 
> 
>> -/* Implementation of json::value::print for json::number.  */
>> +/* Implementation of json::value::print for json::float_number.  */
>>  
>>  void
>> -number::print (pretty_printer *pp) const
>> +float_number::print (pretty_printer *pp) const
>>  {
>>    char tmp[1024];
>>    snprintf (tmp, sizeof (tmp), "%g", m_value);
>>    pp_string (pp, tmp);
>>  }
>>  
>> +/* class json::integer_number, a subclass of json::value, wrapping a long.  */
> 
> Likewise, would it make more sense to call this "long"?
> 
> An idea I had reading your patch: would a template be appropriate here,
> something like:
> 
> template <typename T>
> class number : public value
> {
>   enum kind get_kind () const FINAL OVERRIDE;
>   T get () const { return m_value; }
>   /* etc */
>   
>   T m_value;
> };
> 
> with specializations for "double" and "long"?
> (hence json::number<double> json::number<long>, and enum values in the
> json_kind discriminator>).
> 
> I think that a template might be overthinking things, though;
> the approach in your patch has the virtue of simplicity.
> 
> Is "long" always wide enough for all the integer values we might want
> to express on the host?

Well, I would not over engineer it :)

> 
> [...snip...]
>  
>> -/* Subclass of value for numbers.  */
>> +/* Subclass of value for floats.  */
> 
> I'd write "floating-point numbers" here (given that JSON standard
> talks about "numbers".

Changed.

> 
> [...]
> 
>> +/* Subclass of value for integers.  */
> 
> Likewise "integer-valued numbers" here, or somesuch.

Changed.

> 
> [...]
> 
>> diff --git a/gcc/optinfo-emit-json.cc b/gcc/optinfo-emit-json.cc
>> index 1cfcdfe8948..87cc940133a 100644
>> --- a/gcc/optinfo-emit-json.cc
>> +++ b/gcc/optinfo-emit-json.cc
>> @@ -181,7 +181,7 @@ optrecord_json_writer::impl_location_to_json (dump_impl_location_t loc)
>>  {
>>    json::object *obj = new json::object ();
>>    obj->set ("file", new json::string (loc.m_file));
>> -  obj->set ("line", new json::number (loc.m_line));
>> +  obj->set ("line", new json::float_number (loc.m_line));
> 
> integer here, not float.
> 
>>    if (loc.m_function)
>>      obj->set ("function", new json::string (loc.m_function));
>>    return obj;
>> @@ -196,8 +196,8 @@ optrecord_json_writer::location_to_json (location_t loc)
>>    expanded_location exploc = expand_location (loc);
>>    json::object *obj = new json::object ();
>>    obj->set ("file", new json::string (exploc.file));
>> -  obj->set ("line", new json::number (exploc.line));
>> -  obj->set ("column", new json::number (exploc.column));
>> +  obj->set ("line", new json::float_number (exploc.line));
>> +  obj->set ("column", new json::float_number (exploc.column));
> 
> Likewise, integers here.
> 
>>    return obj;
>>  }
>>  
>> @@ -207,7 +207,7 @@ json::object *
>>  optrecord_json_writer::profile_count_to_json (profile_count count)
>>  {
>>    json::object *obj = new json::object ();
>> -  obj->set ("value", new json::number (count.to_gcov_type ()));
>> +  obj->set ("value", new json::float_number (count.to_gcov_type ()));
> 
> Presumably this should be an integer also.
> 
>>    obj->set ("quality",
>>  	    new json::string (profile_quality_as_string (count.quality ())));
>>    return obj;
>> @@ -262,7 +262,7 @@ optrecord_json_writer::pass_to_json (opt_pass *pass)
>>  	  && (pass->optinfo_flags & optgroup->value))
>>  	optgroups->append (new json::string (optgroup->name));
>>    }
>> -  obj->set ("num", new json::number (pass->static_pass_number));
>> +  obj->set ("num", new json::float_number (pass->static_pass_number));
> 
> Likewise.
> 
>>

And I changed all occurrences of float_number with integer_number
as you suggested.

I'm currently testing the updated patch.
Martin
>From 0863b4e326838fdd16c423bd0b8f59f1dfd7b0f0 Mon Sep 17 00:00:00 2001
From: Martin Liska <mliska@suse.cz>
Date: Wed, 31 Jul 2019 09:51:28 +0200
Subject: [PATCH] Come up with json::integer_number and use it in GCOV.

gcc/ChangeLog:

2019-07-31  Martin Liska  <mliska@suse.cz>

	* diagnostic-format-json.cc (json_from_expanded_location):
	Use json::integer_number.
	* gcov.c (output_intermediate_json_line): Use new
	json::integer_number.
	(output_json_intermediate_file): Likewise.
	* json.cc (number::print): Move to ...
	(float_number::print): ... this.
	(integer_number::print): New.
	(test_writing_numbers): Move to ...
	(test_writing_float_numbers): ... this.
	(test_writing_integer_numbers): New.
	(json_cc_tests): Register test_writing_integer_numbers.
	* json.h (class value): Add forward declaration
	for float_number and integer_number.
	(enum kind): Add JSON_INTEGER and JSON_FLOAT.
	(class number): Move to ...
	(class float_number): ... this.
	(class integer_number): New.
	* optinfo-emit-json.cc (optrecord_json_writer::impl_location_to_json):
	Use json::integer_number.
	(optrecord_json_writer::location_to_json): Likewise.
	(optrecord_json_writer::profile_count_to_json): Likewise.
	(optrecord_json_writer::pass_to_json): Likewise.
---
 gcc/diagnostic-format-json.cc |  4 ++--
 gcc/gcov.c                    | 23 +++++++++++---------
 gcc/json.cc                   | 41 ++++++++++++++++++++++++++++-------
 gcc/json.h                    | 35 ++++++++++++++++++++++++------
 gcc/optinfo-emit-json.cc      | 10 ++++-----
 5 files changed, 81 insertions(+), 32 deletions(-)

diff --git a/gcc/diagnostic-format-json.cc b/gcc/diagnostic-format-json.cc
index 53c3b630b1c..ae812174ad7 100644
--- a/gcc/diagnostic-format-json.cc
+++ b/gcc/diagnostic-format-json.cc
@@ -48,8 +48,8 @@ json_from_expanded_location (location_t loc)
   json::object *result = new json::object ();
   if (exploc.file)
     result->set ("file", new json::string (exploc.file));
-  result->set ("line", new json::number (exploc.line));
-  result->set ("column", new json::number (exploc.column));
+  result->set ("line", new json::integer_number (exploc.line));
+  result->set ("column", new json::integer_number (exploc.column));
   return result;
 }
 
diff --git a/gcc/gcov.c b/gcc/gcov.c
index c65b7153765..ef006d125a2 100644
--- a/gcc/gcov.c
+++ b/gcc/gcov.c
@@ -1061,10 +1061,10 @@ output_intermediate_json_line (json::array *object,
     return;
 
   json::object *lineo = new json::object ();
-  lineo->set ("line_number", new json::number (line_num));
+  lineo->set ("line_number", new json::integer_number (line_num));
   if (function_name != NULL)
     lineo->set ("function_name", new json::string (function_name));
-  lineo->set ("count", new json::number (line->count));
+  lineo->set ("count", new json::integer_number (line->count));
   lineo->set ("unexecuted_block",
 	      new json::literal (line->has_unexecuted_block));
 
@@ -1079,7 +1079,7 @@ output_intermediate_json_line (json::array *object,
 	if (!(*it)->is_unconditional && !(*it)->is_call_non_return)
 	  {
 	    json::object *branch = new json::object ();
-	    branch->set ("count", new json::number ((*it)->count));
+	    branch->set ("count", new json::integer_number ((*it)->count));
 	    branch->set ("throw", new json::literal ((*it)->is_throw));
 	    branch->set ("fallthrough",
 			 new json::literal ((*it)->fall_through));
@@ -1138,16 +1138,19 @@ output_json_intermediate_file (json::array *json_files, source_info *src)
       function->set ("name", new json::string ((*it)->m_name));
       function->set ("demangled_name",
 		     new json::string ((*it)->get_demangled_name ()));
-      function->set ("start_line", new json::number ((*it)->start_line));
-      function->set ("start_column", new json::number ((*it)->start_column));
-      function->set ("end_line", new json::number ((*it)->end_line));
-      function->set ("end_column", new json::number ((*it)->end_column));
+      function->set ("start_line",
+		     new json::integer_number ((*it)->start_line));
+      function->set ("start_column",
+		     new json::integer_number ((*it)->start_column));
+      function->set ("end_line", new json::integer_number ((*it)->end_line));
+      function->set ("end_column",
+		     new json::integer_number ((*it)->end_column));
       function->set ("blocks",
-		     new json::number ((*it)->get_block_count ()));
+		     new json::integer_number ((*it)->get_block_count ()));
       function->set ("blocks_executed",
-		     new json::number ((*it)->blocks_executed));
+		     new json::integer_number ((*it)->blocks_executed));
       function->set ("execution_count",
-		     new json::number ((*it)->blocks[0].count));
+		     new json::integer_number ((*it)->blocks[0].count));
 
       functions->append (function);
     }
diff --git a/gcc/json.cc b/gcc/json.cc
index 512e2e513b9..bec6fc53cc8 100644
--- a/gcc/json.cc
+++ b/gcc/json.cc
@@ -154,18 +154,31 @@ array::append (value *v)
   m_elements.safe_push (v);
 }
 
-/* class json::number, a subclass of json::value, wrapping a double.  */
+/* class json::float_number, a subclass of json::value, wrapping a double.  */
 
-/* Implementation of json::value::print for json::number.  */
+/* Implementation of json::value::print for json::float_number.  */
 
 void
-number::print (pretty_printer *pp) const
+float_number::print (pretty_printer *pp) const
 {
   char tmp[1024];
   snprintf (tmp, sizeof (tmp), "%g", m_value);
   pp_string (pp, tmp);
 }
 
+/* class json::integer_number, a subclass of json::value, wrapping a long.  */
+
+/* Implementation of json::value::print for json::integer_number.  */
+
+void
+integer_number::print (pretty_printer *pp) const
+{
+  char tmp[1024];
+  snprintf (tmp, sizeof (tmp), "%ld", m_value);
+  pp_string (pp, tmp);
+}
+
+
 /* class json::string, a subclass of json::value.  */
 
 /* json::string's ctor.  */
@@ -297,11 +310,22 @@ test_writing_arrays ()
 /* Verify that JSON numbers are written correctly.  */
 
 static void
-test_writing_numbers ()
+test_writing_float_numbers ()
+{
+  assert_print_eq (float_number (0), "0");
+  assert_print_eq (float_number (42), "42");
+  assert_print_eq (float_number (-100), "-100");
+  assert_print_eq (float_number (123456789), "1.23457e+08");
+}
+
+static void
+test_writing_integer_numbers ()
 {
-  assert_print_eq (number (0), "0");
-  assert_print_eq (number (42), "42");
-  assert_print_eq (number (-100), "-100");
+  assert_print_eq (integer_number (0), "0");
+  assert_print_eq (integer_number (42), "42");
+  assert_print_eq (integer_number (-100), "-100");
+  assert_print_eq (integer_number (123456789), "123456789");
+  assert_print_eq (integer_number (-123456789), "-123456789");
 }
 
 /* Verify that JSON strings are written correctly.  */
@@ -337,7 +361,8 @@ json_cc_tests ()
   test_object_get ();
   test_writing_objects ();
   test_writing_arrays ();
-  test_writing_numbers ();
+  test_writing_float_numbers ();
+  test_writing_integer_numbers ();
   test_writing_strings ();
   test_writing_literals ();
 }
diff --git a/gcc/json.h b/gcc/json.h
index d8a690ede5c..316bc8b254c 100644
--- a/gcc/json.h
+++ b/gcc/json.h
@@ -39,7 +39,8 @@ namespace json
 class value;
   class object;
   class array;
-  class number;
+  class float_number;
+  class integer_number;
   class string;
   class literal;
 
@@ -53,8 +54,11 @@ enum kind
   /* class json::array.  */
   JSON_ARRAY,
 
-  /* class json::number.  */
-  JSON_NUMBER,
+  /* class json::integer_number.  */
+  JSON_INTEGER,
+
+  /* class json::float_number.  */
+  JSON_FLOAT,
 
   /* class json::string.  */
   JSON_STRING,
@@ -114,14 +118,14 @@ class array : public value
   auto_vec<value *> m_elements;
 };
 
-/* Subclass of value for numbers.  */
+/* Subclass of value for floating-point numbers.  */
 
-class number : public value
+class float_number : public value
 {
  public:
-  number (double value) : m_value (value) {}
+  float_number (double value) : m_value (value) {}
 
-  enum kind get_kind () const FINAL OVERRIDE { return JSON_NUMBER; }
+  enum kind get_kind () const FINAL OVERRIDE { return JSON_FLOAT; }
   void print (pretty_printer *pp) const FINAL OVERRIDE;
 
   double get () const { return m_value; }
@@ -130,6 +134,23 @@ class number : public value
   double m_value;
 };
 
+/* Subclass of value for integer-valued numbers.  */
+
+class integer_number : public value
+{
+ public:
+  integer_number (long value) : m_value (value) {}
+
+  enum kind get_kind () const FINAL OVERRIDE { return JSON_INTEGER; }
+  void print (pretty_printer *pp) const FINAL OVERRIDE;
+
+  long get () const { return m_value; }
+
+ private:
+  long m_value;
+};
+
+
 /* Subclass of value for strings.  */
 
 class string : public value
diff --git a/gcc/optinfo-emit-json.cc b/gcc/optinfo-emit-json.cc
index 1cfcdfe8948..1ca4f148d15 100644
--- a/gcc/optinfo-emit-json.cc
+++ b/gcc/optinfo-emit-json.cc
@@ -181,7 +181,7 @@ optrecord_json_writer::impl_location_to_json (dump_impl_location_t loc)
 {
   json::object *obj = new json::object ();
   obj->set ("file", new json::string (loc.m_file));
-  obj->set ("line", new json::number (loc.m_line));
+  obj->set ("line", new json::integer_number (loc.m_line));
   if (loc.m_function)
     obj->set ("function", new json::string (loc.m_function));
   return obj;
@@ -196,8 +196,8 @@ optrecord_json_writer::location_to_json (location_t loc)
   expanded_location exploc = expand_location (loc);
   json::object *obj = new json::object ();
   obj->set ("file", new json::string (exploc.file));
-  obj->set ("line", new json::number (exploc.line));
-  obj->set ("column", new json::number (exploc.column));
+  obj->set ("line", new json::integer_number (exploc.line));
+  obj->set ("column", new json::integer_number (exploc.column));
   return obj;
 }
 
@@ -207,7 +207,7 @@ json::object *
 optrecord_json_writer::profile_count_to_json (profile_count count)
 {
   json::object *obj = new json::object ();
-  obj->set ("value", new json::number (count.to_gcov_type ()));
+  obj->set ("value", new json::integer_number (count.to_gcov_type ()));
   obj->set ("quality",
 	    new json::string (profile_quality_as_string (count.quality ())));
   return obj;
@@ -262,7 +262,7 @@ optrecord_json_writer::pass_to_json (opt_pass *pass)
 	  && (pass->optinfo_flags & optgroup->value))
 	optgroups->append (new json::string (optgroup->name));
   }
-  obj->set ("num", new json::number (pass->static_pass_number));
+  obj->set ("num", new json::integer_number (pass->static_pass_number));
   return obj;
 }
 
-- 
2.22.0


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