From 611348e67bd45dcf0322e9a32ce7160c008c3e26 Mon Sep 17 00:00:00 2001
From: Akim Demaille <akim.demaille@gmail.com>
Date: Sun, 20 Dec 2020 09:44:30 +0100
Subject: [PATCH] glr2.cc: more checks

* data/skeletons/glr2.cc: Clarify use of magic numbers.
(glr_stack_item::getState): Check the returned state.
---
 README-hacking.md      | 10 ++++++++++
 data/skeletons/glr2.cc | 15 +++++++++------
 2 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/README-hacking.md b/README-hacking.md
index 028feae2..538f08e2 100644
--- a/README-hacking.md
+++ b/README-hacking.md
@@ -487,6 +487,16 @@ useful.  Here's one way to set ASAN up with GCC 10 on Mac Ports
 
     $ make check-local TESTSUITEFLAGS='-j5 -k cex' ASAN_OPTIONS=detect_leaks=1
 
+5. You might need a suppression file.  See
+   https://github.com/google/sanitizers/wiki/AddressSanitizerLeakSanitizer#suppressions.
+   With G++ on a Mac, you might need a suppression file (say
+   leak.suppression) that contains:
+
+   leak:std::clog
+
+   and pass the additional flags
+   `LSAN_OPTIONS=suppressions=$PWD/leak.suppressions,print_suppressions=0`
+
 ## make maintainer-check-valgrind
 This target uses valgrind both to check bison, and the generated parsers.
 
diff --git a/data/skeletons/glr2.cc b/data/skeletons/glr2.cc
index 0a97937c..abd90256 100644
--- a/data/skeletons/glr2.cc
+++ b/data/skeletons/glr2.cc
@@ -1215,7 +1215,7 @@ public:
 
   glr_stack_item (const glr_stack_item& other) YY_NOEXCEPT YY_NOTHROW
     : is_state_ (other.is_state_)]b4_parse_assert_if([[
-    , magic_ (0xDEAD1ACC)]])[
+    , magic_ (MAGIC)]])[
   {]b4_parse_assert_if([[
     other.check_ ();]])[
     std::memcpy (raw_, other.raw_, union_size);
@@ -1256,7 +1256,9 @@ public:
     check_ ();]])[
     YYDASSERT (is_state ());
     void *yyp = raw_;
-    return *static_cast<glr_state*> (yyp);
+    glr_state& res = *static_cast<glr_state*> (yyp);]b4_parse_assert_if([[
+    res.check_ ();]])[
+    return res;
   }
 
   const glr_state& getState () const
@@ -1264,7 +1266,9 @@ public:
     check_ ();]])[
     YYDASSERT (is_state ());
     const void *yyp = raw_;
-    return *static_cast<const glr_state*> (yyp);
+    const glr_state& res = *static_cast<const glr_state*> (yyp);]b4_parse_assert_if([[
+    res.check_ ();]])[
+    return res;
   }
 
   semantic_option& getOption ()
@@ -1313,7 +1317,7 @@ public:
     YYASSERT (this->is_state_ == false || this->is_state_ == true);
   }
   // A magic number to check our pointer arithmetics is sane.
-  enum { MAGIC = 0xDEAD1ACC };
+  enum { MAGIC = 0xDEAD1ACC }; // 3735886540.
   const unsigned int magic_;]])[
 };
 
@@ -2349,8 +2353,7 @@ public:
         YYASSERT (yyk.get() == 0);
         glr_stack_item* yyrhs = yystateStack.firstTop()->asItem();
         YY_REDUCE_PRINT ((true, yyrhs, yyk, yyrule, yyparser));
-        const YYRESULTTAG res = yyuserAction (yyrule, yynrhs, yyrhs,
-                                yyvalp]b4_locations_if([, yylocp])[);
+        const YYRESULTTAG res = yyuserAction (yyrule, yynrhs, yyrhs, yyvalp]b4_locations_if([, yylocp])[);
         yystateStack.pop_back(static_cast<size_t>(yynrhs));
         yystateStack.setFirstTop(&yystateStack[yystateStack.size() - 1].getState());
         return res;