From: Julian Seward <jseward@acm.org>
Date: Sun, 25 Jan 2009 23:59:24 +0000 (+0000)
Subject: Prior to this commit, exp-ptrcheck would assert if the DWARF3 data for
X-Git-Tag: svn/VALGRIND_3_5_0~1038
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=59e2a184aed3fde65dfa4bd5054adbe1bbb6629f;p=thirdparty%2Fvalgrind.git

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 e5c82bd1af..d4a8e5eda7 100644
--- 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,