Fix llvm-symbolizer to correctly sort a symbol array and calculate symbol sizes

Sometimes, llvm-symbolizer gives wrong results due to incorrect sizes of some symbols. The reason for that was an incorrectly sorted array in computeSymbolSizes. The comparison function used subtraction of unsigned types, which is incorrect. Let's change this to return explicit -1 or 1.

Differential Revision: https://reviews.llvm.org/D26537

llvm-svn: 287028

2 files changed, 41 insertions, 0 deletions

diff --git a/llvm/unittests/Object/CMakeLists.txt b/llvm/unittests/Object/CMakeLists.txt
new file mode 100644
index 00000000000..7a63c167a30
--- /dev/null
+++ b/llvm/unittests/Object/CMakeLists.txt
@@ -0,0 +1,8 @@
+set(LLVM_LINK_COMPONENTS
+  Object
+  )
+
+add_llvm_unittest(ObjectTests
+  SymbolSizeTest.cpp
+  )
+
diff --git a/llvm/unittests/Object/SymbolSizeTest.cpp b/llvm/unittests/Object/SymbolSizeTest.cpp
new file mode 100644
index 00000000000..ad9c40b986d
--- /dev/null
+++ b/llvm/unittests/Object/SymbolSizeTest.cpp
@@ -0,0 +1,33 @@
+//===- SymbolSizeTest.cpp - Tests for SymbolSize.cpp ----------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Object/SymbolSize.h"
+#include "gtest/gtest.h"
+
+using namespace llvm;
+using namespace llvm::object;
+
+TEST(Object, SymbolSizeSort) {
+  auto it = symbol_iterator(SymbolRef());
+  std::vector<SymEntry> Syms{
+      SymEntry{it, 0xffffffff00000000ull, 1, 0},
+      SymEntry{it, 0x00ffffff00000000ull, 2, 0},
+      SymEntry{it, 0x00ffffff000000ffull, 3, 0},
+      SymEntry{it, 0x0000000100000000ull, 4, 0},
+      SymEntry{it, 0x00000000000000ffull, 5, 0},
+      SymEntry{it, 0x00000001000000ffull, 6, 0},
+      SymEntry{it, 0x000000010000ffffull, 7, 0},
+  };
+
+  array_pod_sort(Syms.begin(), Syms.end(), compareAddress);
+
+  for (unsigned I = 0, N = Syms.size(); I < N - 1; ++I) {
+    EXPECT_LE(Syms[I].Address, Syms[I + 1].Address);
+  }
+}