Prior to this commit, exp-ptrcheck would assert if the DWARF3 data for

global or stack blocks described overlapping blocks (which are
nonsensical).  Unfortunately it is naive to assume compilers will
always produce correct debug info.  This commit makes exp-ptrcheck
much more robust against such (inevitable) anomalies: stack and global
blocks which overlap are simply ignored.

--> 3_4_BRANCH

git-svn-id: svn://svn.valgrind.org/valgrind/trunk@9059

diff --git a/exp-ptrcheck/sg_main.c b/exp-ptrcheck/sg_main.c
index e5c82bd1aff95d5ab78e246a2b320eb3fbab4e37..d4a8e5eda7042806ce95d936b498fb1e2f9ae0df 100644 (file)
--- a/exp-ptrcheck/sg_main.c
+++ b/exp-ptrcheck/sg_main.c
@@ -230,13 +230,16 @@ static void pp_StackBlock ( StackBlock* sb )
 static void pp_StackBlocks ( XArray* sbs )
 {
    Word i, n = VG_(sizeXA)( sbs );
-   VG_(printf)("<<< STACKBLOCKS\n" );
+   VG_(message)(Vg_DebugMsg, "<<< STACKBLOCKS" );
    for (i = 0; i < n; i++) {
-      VG_(printf)("   ");
-      pp_StackBlock( (StackBlock*)VG_(indexXA)( sbs, i ) );
-      VG_(printf)("\n");
+      StackBlock* sb = (StackBlock*)VG_(indexXA)( sbs, i );
+      VG_(message)(Vg_DebugMsg,
+         "   StackBlock{ off %ld szB %lu spRel:%c isVec:%c \"%s\" }",
+         sb->base, sb->szB, sb->spRel ? 'Y' : 'N',
+         sb->isVec ? 'Y' : 'N', &sb->name[0] 
+      );
    }
-   VG_(printf)(">>> STACKBLOCKS\n" );
+   VG_(message)(Vg_DebugMsg, ">>> STACKBLOCKS" );
 }
 
 
@@ -332,14 +335,33 @@ static XArray* /* of StackBlock */
      }
    }
 
-   /* A rather poor sanity check on the results. */
+   /* If there are any blocks which overlap and have the same
+      fpRel-ness, junk the whole descriptor; it's obviously bogus.
+      Icc11 certainly generates bogus info from time to time.
+
+      This check is pretty weak; really we ought to have a stronger
+      sanity check. */
    { Word i, n = VG_(sizeXA)( orig );
+     static Int moans = 3;
      for (i = 0; i < n-1; i++) {
        StackBlock* sb1 = (StackBlock*)VG_(indexXA)( orig, i );
        StackBlock* sb2 = (StackBlock*)VG_(indexXA)( orig, i+1 );
-       if (sb1->base == sb2->base)
-          pp_StackBlocks(orig);
-       tl_assert(sb1->base != sb2->base);
+       if (sb1->spRel == sb2->spRel
+           && (sb1->base >= sb2->base
+               || sb1->base + sb1->szB > sb2->base)) {
+          if (moans > 0 && !VG_(clo_xml)) {
+             moans--;
+             VG_(message)(Vg_UserMsg, "Warning: bogus DWARF3 info: "
+                                      "overlapping stack blocks");
+             if (VG_(clo_verbosity) >= 2)
+                pp_StackBlocks(orig);
+             if (moans == 0)
+                VG_(message)(Vg_UserMsg, "Further instances of this "
+                                         "message will not be shown" );
+          }
+          VG_(dropTailXA)( orig, VG_(sizeXA)( orig ));
+          break;
+       }
      }
    }
 
@@ -674,6 +696,7 @@ static void add_block_to_GlobalTree (
    Bool already_present;
    GlobalTreeNode *nyu, *nd;
    UWord keyW, valW;
+   static Int moans = 3;
 
    tl_assert(descr->szB > 0);
    nyu = sg_malloc( "di.sg_main.abtG.1", sizeof(GlobalTreeNode) );
@@ -718,13 +741,25 @@ static void add_block_to_GlobalTree (
    already_present = VG_(addToFM)( gitree, (UWord)nyu, 0 );
    /* The interval can't already be there; else we have
       overlapping global blocks. */
-   if (already_present) {
-      GlobalTree__pp( gitree, "add_block_to_GlobalTree: non-exact duplicate" );
-      VG_(printf)("Overlapping block: ");
-      GlobalTreeNode__pp(nyu);
-      VG_(printf)("\n");
+   /* Unfortunately (25 Jan 09) at least icc11 has been seen to
+      generate overlapping block descriptions in the Dwarf3; clearly
+      bogus. */
+   if (already_present && moans > 0 && !VG_(clo_xml)) {
+      moans--;
+      VG_(message)(Vg_UserMsg, "Warning: bogus DWARF3 info: "
+                               "overlapping global blocks");
+      if (VG_(clo_verbosity) >= 2) {
+         GlobalTree__pp( gitree,
+                         "add_block_to_GlobalTree: non-exact duplicate" );
+         VG_(printf)("Overlapping block: ");
+         GlobalTreeNode__pp(nyu);
+         VG_(printf)("\n");
+      }
+      if (moans == 0)
+         VG_(message)(Vg_UserMsg, "Further instances of this "
+                                  "message will not be shown" );
    }
-   tl_assert(!already_present);
+   /* tl_assert(!already_present); */
 }
 
 static Bool del_GlobalTree_range ( /*MOD*/WordFM* gitree,