This fixes a SIGSEGV failure in ReaderArchive while trying to trace what

InputFile is being pulled from the Archive library to resolve a symbol. 

The buffer which was being used was already being handed over to the
MemoryBuffer object and was being accessed after the hand over. 

Moving it before the buffer is handed over.

llvm-svn: 178838

2 files changed, 27 insertions, 10 deletions

diff --git a/lld/lib/ReaderWriter/ELF/ELFTargetInfo.cpp b/lld/lib/ReaderWriter/ELF/ELFTargetInfo.cpp
index 338096d3a2c..577f5a86107 100644
--- a/lld/lib/ReaderWriter/ELF/ELFTargetInfo.cpp
+++ b/lld/lib/ReaderWriter/ELF/ELFTargetInfo.cpp
@@ -67,7 +67,7 @@ bool ELFTargetInfo::validate(raw_ostream &diagnostics) {
       _entrySymbolName = "_start";
     }
   }
-  
+
   if (_inputFiles.empty()) {
     diagnostics << "No input files\n";
     return true;
@@ -144,14 +144,31 @@ std::unique_ptr<ELFTargetInfo> ELFTargetInfo::create(llvm::Triple triple) {
 }
 
 bool ELFTargetInfo::appendLibrary(StringRef libName) {
-  SmallString<128> fullPath;
+  bool foundFile = false;
+  StringRef pathref;
   for (StringRef dir : _inputSearchPaths) {
-    // FIXME: need to handle other extensions, like .so
-    fullPath.assign(dir);
-    llvm::sys::path::append(fullPath, Twine("lib") + libName + ".a");
-    StringRef pathref = fullPath.str();
-    unsigned pathlen = pathref.size();
-    if (llvm::sys::fs::exists(pathref)) {
+    // Search for dynamic library
+    if (!_isStaticExecutable) {
+      SmallString<128> dynlibPath;
+      dynlibPath.assign(dir);
+      llvm::sys::path::append(dynlibPath, Twine("lib") + libName + ".so");
+      pathref = dynlibPath.str();
+      if (llvm::sys::fs::exists(pathref)) {
+        foundFile = true;
+      }
+    }
+    // Search for static libraries too
+    if (!foundFile) {
+      SmallString<128> archivefullPath;
+      archivefullPath.assign(dir);
+      llvm::sys::path::append(archivefullPath, Twine("lib") + libName + ".a");
+      pathref = archivefullPath.str();
+      if (llvm::sys::fs::exists(pathref)) {
+        foundFile = true;
+      }
+    }
+    if (foundFile) {
+      unsigned pathlen = pathref.size();
       char *x = _extraStrings.Allocate<char>(pathlen);
       memcpy(x, pathref.data(), pathlen);
       appendInputFile(StringRef(x,pathlen));
diff --git a/lld/lib/ReaderWriter/ReaderArchive.cpp b/lld/lib/ReaderWriter/ReaderArchive.cpp
index d3287dd429d..1928e2fa0f7 100644
--- a/lld/lib/ReaderWriter/ReaderArchive.cpp
+++ b/lld/lib/ReaderWriter/ReaderArchive.cpp
@@ -45,9 +45,9 @@ public:
     OwningPtr<MemoryBuffer> buff;
     if (ci->getMemoryBuffer(buff, true))
       return nullptr;
-    std::unique_ptr<MemoryBuffer> mb(buff.take());
     if (_targetInfo.logInputFiles())
       llvm::outs() << buff->getBufferIdentifier() << "\n";
+    std::unique_ptr<MemoryBuffer> mb(buff.take());
     if (_targetInfo.parseFile(mb, result))
       return nullptr;
 
@@ -153,7 +153,7 @@ public:
     }
   }
 
-  std::unordered_map<StringRef, 
+  std::unordered_map<StringRef,
                      llvm::object::Archive::child_iterator> _symbolMemberMap;
 }; // class FileArchive