From a3ccf3ddbd12a0db6522f9990a9e30e535ca76dc Mon Sep 17 00:00:00 2001
From: Kuba Brecka <kuba.brecka@gmail.com>
Date: Tue, 15 Nov 2016 21:07:03 +0000
Subject: 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
---
 llvm/unittests/Object/SymbolSizeTest.cpp | 33 ++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)
 create mode 100644 llvm/unittests/Object/SymbolSizeTest.cpp

(limited to 'llvm/unittests/Object/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);
+  }
+}
-- 
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