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From: Matthias Maennich <maennich@google.com>
To: Giuliano Procida <gprocida@google.com>
Cc: libabigail@sourceware.org, dodji@seketeli.org, kernel-team@android.com
Subject: Re: [PATCH v3] Fix size calculations for multidimensional arrays.
Date: Sat, 28 Mar 2020 14:38:07 +0100	[thread overview]
Message-ID: <20200328133807.GA101337@google.com> (raw)
In-Reply-To: <20200326165927.110863-1-gprocida@google.com>

On Thu, Mar 26, 2020 at 04:59:27PM +0000, Giuliano Procida wrote:
>The code in abg-ir.cc that calculated the memory size of an array
>summed, rather than multiplied, the dimensions. It also did duplicate
>work for each dimension after the first.
>
>Existing code in abg-reader.cc asserted that array size information
>read from XML match freshly calculated values.
>
>This patch corrects the calculation, eliminates the duplicate work and
>updates the XML reader validation to just emit a warning if old bad
>array size information is found.
>
>	* include/abg-ir.h (array_type_def::append_subrange): Remove
>	this function.
>	* src/abg-ir.cc (array_type_def::set_element_type): Add a note
>	about safe usage.
>	(array_type_def::append_subrange): Inline this function into
>	its only caller append_subranges and remove it.
>	(array_type_def::append_subranges): Do correct multiplicative
>	calculation of multidimensional array sizes.
>	* src/abg-reader.cc: (build_elf_symbol_db): Fix code
>	indentation.
>	(build_array_type_def): Tabify. When checking calculated
>	against read array sizes, warn once if value matches old
>	behaviour rather than raising an assertion.
>	* tests/data/test-annotate/test14-pr18893.so.abi: Correct
>	array sizes.
>	* tests/data/test-annotate/test17-pr19027.so.abi: Ditto.
>	* tests/data/test-annotate/test19-pr19023-libtcmalloc_and_profiler.so.abi:
>	Ditto.
>	* tests/data/test-annotate/test7.so.abi: Ditto.
>	* tests/data/test-diff-dwarf/test10-report.txt: Ditto.
>	* tests/data/test-diff-dwarf/test11-report.txt: Ditto.
>	* tests/data/test-read-write/test25.xml: Ditto.
>
>Signed-off-by: Giuliano Procida <gprocida@google.com>
>---
> include/abg-ir.h                              |  3 -
> src/abg-ir.cc                                 | 31 +++----
> src/abg-reader.cc                             | 80 ++++++++++++-------
> .../data/test-annotate/test14-pr18893.so.abi  |  8 +-
> .../data/test-annotate/test17-pr19027.so.abi  |  2 +-
> ...19-pr19023-libtcmalloc_and_profiler.so.abi |  2 +-
> tests/data/test-annotate/test7.so.abi         |  2 +-
> tests/data/test-diff-dwarf/test10-report.txt  |  2 +-
> tests/data/test-diff-dwarf/test11-report.txt  |  4 +-
> tests/data/test-read-write/test25.xml         |  2 +-
> 10 files changed, 78 insertions(+), 58 deletions(-)
>
>diff --git a/include/abg-ir.h b/include/abg-ir.h
>index 1278da94..fda10de5 100644
>--- a/include/abg-ir.h
>+++ b/include/abg-ir.h
>@@ -2380,9 +2380,6 @@ public:
>   void
>   set_element_type(const type_base_sptr& element_type);
>
>-  virtual void
>-  append_subrange(subrange_sptr sub);
>-
>   virtual void
>   append_subranges(const std::vector<subrange_sptr>& subs);
>
>diff --git a/src/abg-ir.cc b/src/abg-ir.cc
>index a10b0bb7..5576c137 100644
>--- a/src/abg-ir.cc
>+++ b/src/abg-ir.cc
>@@ -14558,6 +14558,10 @@ array_type_def::get_element_type() const
> /// re-compute the canonical type of the array, if one has already
> /// been computed.
> ///
>+/// The intended use of this method is to permit in-place adjustment
>+/// of the element type's qualifiers. In particular, the size of the
>+/// element type should not be changed.
>+///
> /// @param element_type the new element type to set.
> void
> array_type_def::set_element_type(const type_base_sptr& element_type)
>@@ -14565,29 +14569,26 @@ array_type_def::set_element_type(const type_base_sptr& element_type)
>   priv_->element_type_ = element_type;
> }
>
>-// Append a single subrange @param sub.
>-void
>-array_type_def::append_subrange(subrange_sptr sub)
>-{
>-  priv_->subranges_.push_back(sub);
>-  size_t s = get_size_in_bits();
>-  s += sub->get_length() * get_element_type()->get_size_in_bits();
>-  set_size_in_bits(s);
>-  string r = get_pretty_representation();
>-  const environment* env = get_environment();
>-  ABG_ASSERT(env);
>-  set_name(env->intern(r));
>-}
>-
> /// Append subranges from the vector @param subs to the current
> /// vector of subranges.
> void
> array_type_def::append_subranges(const std::vector<subrange_sptr>& subs)
> {
>+  size_t s = get_element_type()->get_size_in_bits();
>+
>   for (std::vector<shared_ptr<subrange_type> >::const_iterator i = subs.begin();
>        i != subs.end();
>        ++i)
>-    append_subrange(*i);
>+    {
>+      priv_->subranges_.push_back(*i);
>+      s *= (*i)->get_length();
>+    }
>+
>+  const environment* env = get_environment();
>+  ABG_ASSERT(env);
>+  string r = get_pretty_representation();
>+  set_name(env->intern(r));

set_name(env->intern(get_pretty_representation()));


>+  set_size_in_bits(s);
> }
>
> /// @return true if one of the sub-ranges of the array is infinite, or
>diff --git a/src/abg-reader.cc b/src/abg-reader.cc
>index 0dcb2e92..31f83ca2 100644
>--- a/src/abg-reader.cc
>+++ b/src/abg-reader.cc
>@@ -39,6 +39,8 @@
> #include "abg-suppression-priv.h"
>
> #include "abg-internal.h"
>+#include "abg-tools-utils.h"
>+
> // <headers defining libabigail's API go under here>
> ABG_BEGIN_EXPORT_DECLARATIONS
>
>@@ -3003,24 +3005,24 @@ build_elf_symbol_db(read_context& ctxt,
>     {
>       if (xml_char_sptr s = XML_NODE_GET_ATTRIBUTE(x->first, "alias"))
> 	{
>-      string alias_id = CHAR_STR(s);
>-
>-      // Symbol aliases can be multiple separated by comma(,), split them
>-      std::vector<std::string> elems;
>-      std::stringstream aliases(alias_id);
>-      std::string item;
>-      while (std::getline(aliases, item, ','))
>-        elems.push_back(item);
>-      for (std::vector<string>::iterator alias = elems.begin();
>-           alias != elems.end(); ++alias)
>-        {
>-          string_elf_symbol_sptr_map_type::const_iterator i =
>-          id_sym_map.find(*alias);
>-          ABG_ASSERT(i != id_sym_map.end());
>-          ABG_ASSERT(i->second->is_main_symbol());
>-
>-          x->second->get_main_symbol()->add_alias(i->second);
>-        }
>+	  string alias_id = CHAR_STR(s);
>+
>+	  // Symbol aliases can be multiple separated by comma(,), split them
>+	  std::vector<std::string> elems;
>+	  std::stringstream aliases(alias_id);
>+	  std::string item;
>+	  while (std::getline(aliases, item, ','))
>+	    elems.push_back(item);
>+	  for (std::vector<string>::iterator alias = elems.begin();
>+	       alias != elems.end(); ++alias)
>+	    {
>+	      string_elf_symbol_sptr_map_type::const_iterator i =
>+	      id_sym_map.find(*alias);
>+	      ABG_ASSERT(i != id_sym_map.end());
>+	      ABG_ASSERT(i->second->is_main_symbol());
>+
>+	      x->second->get_main_symbol()->add_alias(i->second);
>+	    }

This is a whitespace only commit and needs to probably go into a
separate change.

> 	}
>     }
>
>@@ -4019,12 +4021,12 @@ build_array_type_def(read_context&	ctxt,
>     {
>       size_in_bits = strtoull(CHAR_STR(s), &endptr, 0);
>       if (*endptr != '\0')
>-        {
>-          if (!strcmp(CHAR_STR(s), "infinite"))
>-            size_in_bits = (size_t) -1;
>-          else
>-            return nil;
>-        }
>+	{
>+	  if (!strcmp(CHAR_STR(s), "infinite"))
>+	    size_in_bits = (size_t) -1;
>+	  else
>+	    return nil;
>+	}

As above

>       has_size_in_bits = true;
>     }
>
>@@ -4032,7 +4034,7 @@ build_array_type_def(read_context&	ctxt,
>     {
>       alignment_in_bits = strtoull(CHAR_STR(s), &endptr, 0);
>       if (*endptr != '\0')
>-        return nil;
>+	return nil;
>     }
>
>   string id;
>@@ -4076,11 +4078,31 @@ build_array_type_def(read_context&	ctxt,
>     return nil;
>
>   if (has_size_in_bits)
>-    if (size_in_bits != ar_type->get_size_in_bits())
>+    if (size_in_bits != (size_t) -1
>+	&& size_in_bits != ar_type->get_size_in_bits())
>       {
>-	ABG_ASSERT(size_in_bits == (size_t) -1
>-	       || ar_type->get_element_type()->get_size_in_bits() == (size_t)-1
>-	       || ar_type->get_element_type()->get_size_in_bits() == 0);
>+	// We have a potential discrepancy between calculated and recorded sizes.
>+	size_t element_size = ar_type->get_element_type()->get_size_in_bits();
>+	if (element_size && element_size != (size_t)-1)
>+	  {
>+	    // Older versions miscalculated multidimensional array sizes.
>+	    size_t bad_count = 0;
>+	    for (vector<array_type_def::subrange_sptr>::const_iterator i = subranges.begin();

Line length.

>+		 i != subranges.end(); ++i)
>+	      bad_count += (*i)->get_length();
>+	    if (size_in_bits == bad_count * element_size)
>+	      {
>+		static bool reported = false;
>+		if (!reported)
>+		  {
>+		    std::cerr << "warning: ignoring bad array sizes in XML"
>+			      << std::endl;

Should we provide more data for this finding? Like what was the
discrepancy?

>+		    reported = true;
>+		  }
>+	      }
>+	    else

Emit an error message before dying.

With the above addressed, please feel free to add
Reviewed-by: Matthias Maennich <maennich@google.com>

Cheers,
Matthias

>+	      ABG_ASSERT_NOT_REACHED;
>+	  }
>       }
>
>   if (ctxt.push_and_key_type_decl(ar_type, id, add_to_current_scope))
>diff --git a/tests/data/test-annotate/test14-pr18893.so.abi b/tests/data/test-annotate/test14-pr18893.so.abi
>index d357bfbd..c7baf6ad 100644
>--- a/tests/data/test-annotate/test14-pr18893.so.abi
>+++ b/tests/data/test-annotate/test14-pr18893.so.abi
>@@ -5047,7 +5047,7 @@
>
>     </array-type-def>
>     <!-- REAL[40][4] -->
>-    <array-type-def dimensions='2' type-id='type-id-122' size-in-bits='1408' id='type-id-156'>
>+    <array-type-def dimensions='2' type-id='type-id-122' size-in-bits='5120' id='type-id-156'>
>       <!-- <anonymous range>[40] -->
>       <subrange length='40' type-id='type-id-32' id='type-id-126'/>
>
>@@ -9621,7 +9621,7 @@
>   </abi-instr>
>   <abi-instr version='1.0' address-size='64' path='libnurbs/internals/backend.cc' comp-dir-path='/tmp/legendre/spack-stage/spack-stage-T0fsxk/Mesa-8.0.5/src/glu/sgi' language='LANG_C_plus_plus'>
>     <!-- REAL[3][4] -->
>-    <array-type-def dimensions='2' type-id='type-id-122' size-in-bits='224' id='type-id-292'>
>+    <array-type-def dimensions='2' type-id='type-id-122' size-in-bits='384' id='type-id-292'>
>       <!-- <anonymous range>[3] -->
>       <subrange length='3' type-id='type-id-32' id='type-id-35'/>
>
>@@ -10572,7 +10572,7 @@
>
>     </array-type-def>
>     <!-- REAL[5][5] -->
>-    <array-type-def dimensions='2' type-id='type-id-122' size-in-bits='320' id='type-id-321'>
>+    <array-type-def dimensions='2' type-id='type-id-122' size-in-bits='800' id='type-id-321'>
>       <!-- <anonymous range>[5] -->
>       <subrange length='5' type-id='type-id-32' id='type-id-320'/>
>
>@@ -13394,7 +13394,7 @@
>
>     </array-type-def>
>     <!-- REAL[2][5] -->
>-    <array-type-def dimensions='2' type-id='type-id-122' size-in-bits='224' id='type-id-379'>
>+    <array-type-def dimensions='2' type-id='type-id-122' size-in-bits='320' id='type-id-379'>
>       <!-- <anonymous range>[2] -->
>       <subrange length='2' type-id='type-id-32' id='type-id-191'/>
>
>diff --git a/tests/data/test-annotate/test17-pr19027.so.abi b/tests/data/test-annotate/test17-pr19027.so.abi
>index fae390c6..9214a0f4 100644
>--- a/tests/data/test-annotate/test17-pr19027.so.abi
>+++ b/tests/data/test-annotate/test17-pr19027.so.abi
>@@ -1296,7 +1296,7 @@
>
>     </array-type-def>
>     <!-- hb_codepoint_t[2][5] -->
>-    <array-type-def dimensions='2' type-id='type-id-64' size-in-bits='224' id='type-id-65'>
>+    <array-type-def dimensions='2' type-id='type-id-64' size-in-bits='320' id='type-id-65'>
>       <!-- <anonymous range>[2] -->
>       <subrange length='2' type-id='type-id-4' id='type-id-8'/>
>
>diff --git a/tests/data/test-annotate/test19-pr19023-libtcmalloc_and_profiler.so.abi b/tests/data/test-annotate/test19-pr19023-libtcmalloc_and_profiler.so.abi
>index 64c8c395..b62486d9 100644
>--- a/tests/data/test-annotate/test19-pr19023-libtcmalloc_and_profiler.so.abi
>+++ b/tests/data/test-annotate/test19-pr19023-libtcmalloc_and_profiler.so.abi
>@@ -38460,7 +38460,7 @@
>
>     </array-type-def>
>     <!-- void*[20][32] -->
>-    <array-type-def dimensions='2' type-id='type-id-17' size-in-bits='3328' id='type-id-434'>
>+    <array-type-def dimensions='2' type-id='type-id-17' size-in-bits='40960' id='type-id-434'>
>       <!-- <anonymous range>[20] -->
>       <subrange length='20' type-id='type-id-3' id='type-id-10'/>
>
>diff --git a/tests/data/test-annotate/test7.so.abi b/tests/data/test-annotate/test7.so.abi
>index 294bac3c..11bd6a3d 100644
>--- a/tests/data/test-annotate/test7.so.abi
>+++ b/tests/data/test-annotate/test7.so.abi
>@@ -34,7 +34,7 @@
>     <!-- double -->
>     <type-decl name='double' size-in-bits='64' id='type-id-10'/>
>     <!-- double[5][3] -->
>-    <array-type-def dimensions='2' type-id='type-id-10' size-in-bits='512' id='type-id-11'>
>+    <array-type-def dimensions='2' type-id='type-id-10' size-in-bits='960' id='type-id-11'>
>       <!-- <anonymous range>[5] -->
>       <subrange length='5' type-id='type-id-4' id='type-id-12'/>
>
>diff --git a/tests/data/test-diff-dwarf/test10-report.txt b/tests/data/test-diff-dwarf/test10-report.txt
>index 96e0d46c..0f616713 100644
>--- a/tests/data/test-diff-dwarf/test10-report.txt
>+++ b/tests/data/test-diff-dwarf/test10-report.txt
>@@ -10,7 +10,7 @@ Variables changes summary: 0 Removed, 0 Changed, 0 Added variable
>         2 data member changes:
>           type of 'int S::m0[5][3]' changed:
>             type name changed from 'int[5][3]' to 'int[5][4]'
>-            array type size changed from 256 to 288
>+            array type size changed from 480 to 640
>             array type subrange 2 changed length from 3 to 4
>           type of 'int* S::m1[10]' changed:
>             array element type 'int*' changed:
>diff --git a/tests/data/test-diff-dwarf/test11-report.txt b/tests/data/test-diff-dwarf/test11-report.txt
>index 0979602f..655802f2 100644
>--- a/tests/data/test-diff-dwarf/test11-report.txt
>+++ b/tests/data/test-diff-dwarf/test11-report.txt
>@@ -10,11 +10,11 @@ Variables changes summary: 0 Removed, 0 Changed, 0 Added variable
>         2 data member changes:
>           type of 'int S::m0[5][3]' changed:
>             type name changed from 'int[5][3]' to 'int[6][3]'
>-            array type size changed from 256 to 288
>+            array type size changed from 480 to 576
>             array type subrange 1 changed length from 5 to 6
>           type of 'int S::m1[6][4]' changed:
>             type name changed from 'int[6][4]' to 'int[6][5]'
>-            array type size changed from 320 to 352
>+            array type size changed from 768 to 960
>             array type subrange 2 changed length from 4 to 5
>           and offset changed from 480 to 576 (in bits) (by +96 bits)
>
>diff --git a/tests/data/test-read-write/test25.xml b/tests/data/test-read-write/test25.xml
>index 9be61cce..5be51f85 100644
>--- a/tests/data/test-read-write/test25.xml
>+++ b/tests/data/test-read-write/test25.xml
>@@ -26,7 +26,7 @@
>     </data-member>
>   </class-decl>
>   <type-decl name='double' size-in-bits='64' alignment-in-bits='64' id='type-id-11'/>
>-  <array-type-def dimensions='2' type-id='type-id-11' size-in-bits='512' alignment-in-bits='64' id='type-id-9'>
>+  <array-type-def dimensions='2' type-id='type-id-11' size-in-bits='960' alignment-in-bits='64' id='type-id-9'>
>     <subrange length='5' id='type-id-12'/>
>
>     <subrange length='3' id='type-id-13'/>
>-- 
>2.25.1.696.g5e7596f4ac-goog
>

  reply	other threads:[~2020-03-28 13:38 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-26 16:24 [PATCH] " Giuliano Procida
2020-03-26 16:49 ` [PATCH v2] " Giuliano Procida
2020-03-26 16:59   ` [PATCH v3] " Giuliano Procida
2020-03-28 13:38     ` Matthias Maennich [this message]
2020-03-28 19:49       ` Giuliano Procida
2020-03-28 19:53 ` [PATCH v2] " Giuliano Procida
2020-03-28 20:09   ` Giuliano Procida

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