Handle properly the case of an inlined call that has no abstract origin attribute.

Normally, an inlined call has a dwarf entry that points at the abstract origin, i.e. the
function that was inlined.
However, in some cases, the abstract origin tag is not present (observed with gcc 6.3.0, when
compiling with link time optimisation).
Such missing abstract origin was then causing an error message when reading the dwarf debug info.

This patch ensures we handle this case more gracefully, by using UnknownInlinedFun as inlined
function name for such a missing abstract origin;

diff --git a/coregrind/m_debuginfo/readdwarf3.c b/coregrind/m_debuginfo/readdwarf3.c
index 2f538c9e4d4ff7bd6b5ce5d0bf0fa062e13e8e4f..e9a3816a58472b58a968737417c439ee03eaa151 100644 (file)
--- a/coregrind/m_debuginfo/readdwarf3.c
+++ b/coregrind/m_debuginfo/readdwarf3.c
@@ -2585,6 +2585,23 @@ static const HChar* get_inlFnName (Int absori, const CUConst* cc, Bool td3)
    FormContents cts;
    UInt nf_i;
 
+   /* Some inlined subroutine call dwarf entries do not have the abstract
+      origin attribute, resulting in absori being 0 (see callers of
+      get_inlFnName). This is observed at least with gcc 6.3.0 when compiling
+      valgrind with lto. So, in case we have a 0 absori, do not report an
+      error, instead, rather return an unknown inlined function. */
+   if (absori == 0) {
+      static Bool absori0_reported = False;
+      if (!absori0_reported && VG_(clo_verbosity) > 1) {
+         VG_(message)(Vg_DebugMsg,
+                      "Warning: inlined fn name without absori\n"
+                      "is shown as UnknownInlinedFun\n");
+         absori0_reported = True;
+      }
+      TRACE_D3(" <get_inlFnName>: absori is not set");
+      return ML_(addStr)(cc->di, "UnknownInlinedFun", -1);
+   }
+
    posn = uncook_die( cc, absori, &type_flag, &alt_flag);
    if (type_flag)
       cc->barf("get_inlFnName: uncooked absori in type debug info");
@@ -2743,6 +2760,7 @@ static Bool parse_inl_DIE (
       UInt   caller_fndn_ix = 0;
       Int caller_lineno = 0;
       Int inlinedfn_abstract_origin = 0;
+      // 0 will be interpreted as no abstract origin by get_inlFnName
 
       nf_i = 0;
       while (True) {