From 14f79a8eae1542756ae962d6605a06cf05bcead2 Mon Sep 17 00:00:00 2001
From: Jordan Rupprecht <rupprecht@google.com>
Date: Fri, 1 Feb 2019 21:04:16 +0000
Subject: [PATCH] [DebugInfo] Don't use realpath when looking up debug binary
 locations.

Summary:
Using realpath makes assumptions about build systems that do not always hold true. The debug binary referred to from the .gnu_debuglink should exist in the same directory (or in a .debug directory, etc.), but the files may only exist as symlinks to a differently named files elsewhere, and using realpath causes that lookup to fail.

This was added in r189250, and this is basically a revert + regression test case.

Reviewers: dblaikie, samsonov, jhenderson

Reviewed By: dblaikie

Subscribers: llvm-commits, hiraditya

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D57609

llvm-svn: 352916
---
 lib/DebugInfo/Symbolize/Symbolize.cpp           | 11 +----------
 .../symbolize-gnu-debuglink-no-realpath.test    | 17 +++++++++++++++++
 2 files changed, 18 insertions(+), 10 deletions(-)
 create mode 100644 test/DebugInfo/symbolize-gnu-debuglink-no-realpath.test

diff --git a/lib/DebugInfo/Symbolize/Symbolize.cpp b/lib/DebugInfo/Symbolize/Symbolize.cpp
index 1d5852d12fb..5f7370c9ae5 100644
--- a/lib/DebugInfo/Symbolize/Symbolize.cpp
+++ b/lib/DebugInfo/Symbolize/Symbolize.cpp
@@ -16,7 +16,6 @@
 
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/BinaryFormat/COFF.h"
-#include "llvm/Config/config.h"
 #include "llvm/DebugInfo/DWARF/DWARFContext.h"
 #include "llvm/DebugInfo/PDB/PDB.h"
 #include "llvm/DebugInfo/PDB/PDBContext.h"
@@ -33,7 +32,6 @@
 #include "llvm/Support/Path.h"
 #include <algorithm>
 #include <cassert>
-#include <cstdlib>
 #include <cstring>
 
 #if defined(_MSC_VER)
@@ -168,14 +166,7 @@ bool checkFileCRC(StringRef Path, uint32_t CRCHash) {
 bool findDebugBinary(const std::string &OrigPath,
                      const std::string &DebuglinkName, uint32_t CRCHash,
                      std::string &Result) {
-  std::string OrigRealPath = OrigPath;
-#if defined(HAVE_REALPATH)
-  if (char *RP = realpath(OrigPath.c_str(), nullptr)) {
-    OrigRealPath = RP;
-    free(RP);
-  }
-#endif
-  SmallString<16> OrigDir(OrigRealPath);
+  SmallString<16> OrigDir(OrigPath);
   llvm::sys::path::remove_filename(OrigDir);
   SmallString<16> DebugPath = OrigDir;
   // Try /path/to/original_binary/debuglink_name
diff --git a/test/DebugInfo/symbolize-gnu-debuglink-no-realpath.test b/test/DebugInfo/symbolize-gnu-debuglink-no-realpath.test
new file mode 100644
index 00000000000..d6be5efc812
--- /dev/null
+++ b/test/DebugInfo/symbolize-gnu-debuglink-no-realpath.test
@@ -0,0 +1,17 @@
+# REQUIRES: shell
+# Ensure that no realpath assumptions are made about .gnu_debuglink paths.
+
+# Copy inputs to some other location with arbitrary names, with the original
+# filenames just being symlinks to the copies. Real files go in the "real" dir,
+# symlinks (with original names) go in "syms".
+RUN: rm -rf %t/real %t/syms
+RUN: mkdir %t/real %t/syms
+RUN: cp %p/Inputs/dwarfdump-test.elf-x86-64 %t/real/prog
+RUN: cp %p/Inputs/dwarfdump-test.elf-x86-64.debuglink %t/real/link
+RUN: ln -s %t/real/prog %t/syms/dwarfdump-test.elf-x86-64
+RUN: ln -s %t/real/link %t/syms/dwarfdump-test.elf-x86-64.debuglink
+
+RUN: llvm-symbolizer --obj=%t/syms/dwarfdump-test.elf-x86-64.debuglink 0x40113f | FileCheck %s
+
+CHECK:       main
+CHECK-NEXT: /tmp/dbginfo{{[/\\]}}dwarfdump-test.cc:16