[compiler-rt] [TSan][compiler-rt] Defer symbolization of Reports to as late as possible (PR #151120)

[Thurston Dang via llvm-commits]

================
@@ -199,6 +198,80 @@ void ScopedReportBase::AddMemoryAccess(uptr addr, uptr external_tag, Shadow s,
   }
 }
 
+void ScopedReportBase::SymbolizeStackElems() {
+  // symbolize memory ops
+  for (usize i = 0; i < rep_->mops.Size(); i++) {
+    ReportMop *mop = rep_->mops[i];
+    mop->stack = SymbolizeStack(mop->stack_trace);
+    if (mop->stack)
+      mop->stack->suppressable = true;
+  }
+
+  Vector<ReportLocation *> locs_tmp;
+
+  // Repopulate the locations in the order they were added - take care with
+  // the added locations
+  usize locs_idx = 0;
+  for (usize i = 0; i < rep_->added_location_addrs.Size(); i++) {
+    AddedLocationAddr *added_loc_addr = &rep_->added_location_addrs[i];
+
+    for (; locs_idx < added_loc_addr->locs_idx; locs_idx++) {
+      ReportLocation *loc = rep_->locs[locs_idx];
+      loc->stack = SymbolizeStackId(loc->stack_id);
+      locs_tmp.PushBack(loc);
+    }
+
+    if (ReportLocation *added_loc = SymbolizeData(added_loc_addr->addr)) {
+      added_loc->suppressable = true;
+      locs_tmp.PushBack(added_loc);
+    }
+  }
+
+  // Append any remaining locations
+  for (; locs_idx < rep_->locs.Size(); locs_idx++) {
+    ReportLocation *loc = rep_->locs[locs_idx];
+    loc->stack = SymbolizeStackId(loc->stack_id);
+    locs_tmp.PushBack(loc);
+  }
+
+  rep_->locs.Reset();
+  for (usize i = 0; i < locs_tmp.Size(); i++) rep_->locs.PushBack(locs_tmp[i]);
+
+  // symbolize locations
+  for (usize i = 0; i < rep_->locs.Size(); i++) {
+    ReportLocation *loc = rep_->locs[i];
+    loc->stack = SymbolizeStackId(loc->stack_id);
+  }
+
+  usize offset = 0;
+  for (usize i = 0; i < rep_->added_location_addrs.Size(); i++) {
+    struct AddedLocationAddr *added_loc = &rep_->added_location_addrs[i];
+    if (ReportLocation *loc = SymbolizeData(added_loc->addr)) {
+      offset++;
+      loc->suppressable = true;
+      rep_->locs[added_loc->locs_idx] = loc;
+    }
+  }
----------------
thurstond wrote:

IIUC this is inserting elements from rep_->added_location_addrs into the correct place in rep_->locs (a small portion is calling the symbolized), but it's a lot of work. I think it can be simplified by adding placeholders in ScopedReportBase::AddLocation (see comment below).

https://github.com/llvm/llvm-project/pull/151120