[llvm] r344001 - [PDB] fix a bug in global stream name lookup.

[Zachary Turner via llvm-commits]

Author: zturner
Date: Mon Oct  8 15:38:27 2018
New Revision: 344001

URL: http://llvm.org/viewvc/llvm-project?rev=344001&view=rev
Log:
[PDB] fix a bug in global stream name lookup.

When we're looking up a record in the last hash bucket chain, we
need to be careful with the end-offset calculation.

Modified:
    llvm/trunk/lib/DebugInfo/PDB/Native/GlobalsStream.cpp
    llvm/trunk/test/DebugInfo/PDB/pdbdump-global-lookup.test

Modified: llvm/trunk/lib/DebugInfo/PDB/Native/GlobalsStream.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/DebugInfo/PDB/Native/GlobalsStream.cpp?rev=344001&r1=344000&r2=344001&view=diff
==============================================================================
--- llvm/trunk/lib/DebugInfo/PDB/Native/GlobalsStream.cpp (original)
+++ llvm/trunk/lib/DebugInfo/PDB/Native/GlobalsStream.cpp Mon Oct  8 15:38:27 2018
@@ -57,13 +57,16 @@ GlobalsStream::findRecordsByName(StringR
     return Result;
 
   uint32_t ChainStartOffset = GlobalsTable.HashBuckets[CompressedBucketIndex];
-  uint32_t NextChainStart = GlobalsTable.HashBuckets.size();
-  if (static_cast<uint32_t>(CompressedBucketIndex + 1) < NextChainStart)
-    NextChainStart = GlobalsTable.HashBuckets[CompressedBucketIndex + 1];
+  uint32_t NextChainOffset = GlobalsTable.HashBuckets.size() * 12;
+  uint32_t LastBucketIndex = GlobalsTable.HashBuckets.size() - 1;
+  if (static_cast<uint32_t>(CompressedBucketIndex) < LastBucketIndex) {
+    NextChainOffset = GlobalsTable.HashBuckets[CompressedBucketIndex + 1];
+  }
   ChainStartOffset /= 12;
-  NextChainStart /= 12;
+  NextChainOffset /= 12;
 
-  while (ChainStartOffset < NextChainStart) {
+  auto &Back = GlobalsTable.HashRecords.back();
+  while (ChainStartOffset < NextChainOffset) {
     PSHashRecord PSH = GlobalsTable.HashRecords[ChainStartOffset];
     uint32_t Off = PSH.Off - 1;
     codeview::CVSymbol Record = Symbols.readRecord(Off);

Modified: llvm/trunk/test/DebugInfo/PDB/pdbdump-global-lookup.test
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/PDB/pdbdump-global-lookup.test?rev=344001&r1=344000&r2=344001&view=diff
==============================================================================
--- llvm/trunk/test/DebugInfo/PDB/pdbdump-global-lookup.test (original)
+++ llvm/trunk/test/DebugInfo/PDB/pdbdump-global-lookup.test Mon Oct  8 15:38:27 2018
@@ -4,6 +4,12 @@
 ; RUN:    -global-name=abcdefg \
 ; RUN:    %p/Inputs/every-function.pdb | FileCheck %s
 
+; This is a separate command line invocation because B::PureFunc
+; is special.  It's in the last hash bucket, so it exercises a special
+; calculation path.
+; RUN: llvm-pdbutil dump -globals -global-name=B::PureFunc \
+; RUN:    %p/Inputs/symbolformat.pdb | FileCheck --check-prefix=PURE %s
+
 CHECK:                        Global Symbols
 CHECK-NEXT: ============================================================
 CHECK-NEXT:     Global Name `operator delete`
@@ -16,3 +22,9 @@ CHECK-NEXT:       2016 | S_PROCREF [size
 CHECK-NEXT:              module = 1, sum name = 0, offset = 1952
 CHECK-NEXT:     Global Name `abcdefg`
 CHECK-NEXT:       (no matching records found)
+
+PURE:                        Global Symbols
+PURE-NEXT: ============================================================
+PURE-NEXT:     Global Name `B::PureFunc`
+PURE-NEXT:        980 | S_PROCREF [size = 28] `B::PureFunc`
+PURE-NEXT:              module = 1, sum name = 0, offset = 800