Rebased PNaCl localmods in LLVM to 223109

tools/gold/gold-plugin.cpp

Index: tools/gold/gold-plugin.cpp
diff --git a/tools/gold/gold-plugin.cpp b/tools/gold/gold-plugin.cpp
index b7d8c5e14c688ee3fc350a992742aa41cba3b79a..24a40829e9d6ec05f167413a8f6db130ebb85ea1 100644
--- a/tools/gold/gold-plugin.cpp
+++ b/tools/gold/gold-plugin.cpp
@@ -78,6 +78,14 @@ static std::list<claimed_file> Modules;
 static std::vector<std::string> Cleanup;
 static llvm::TargetOptions TargetOpts;
 
+// @LOCALMOD-BEGIN
+// Callback for getting the number of --wrap'd symbols.
+static ld_plugin_get_num_wrapped get_num_wrapped = NULL;
+
+// Callback for getting the name of a wrapped symbol.
+static ld_plugin_get_wrapped get_wrapped = NULL;
+// @LOCALMOD-END
+
 namespace options {
   enum OutputType {
     OT_NORMAL,
@@ -223,6 +231,14 @@ ld_plugin_status onload(ld_plugin_tv *tv) {
       case LDPT_GET_VIEW:
         get_view = tv->tv_u.tv_get_view;
         break;
+      // @LOCALMOD-BEGIN
+      case LDPT_GET_WRAPPED:
+        get_wrapped = tv->tv_u.tv_get_wrapped;
+        break;
+      case LDPT_GET_NUM_WRAPPED:
+        get_num_wrapped = tv->tv_u.tv_get_num_wrapped;
+        break;
+      // @LOCALMOD-END
       case LDPT_MESSAGE:
         message = tv->tv_u.tv_message;
         break;
@@ -543,11 +559,9 @@ static Constant *mapConstantToLocalCopy(Constant *C, ValueToValueMapTy &VM,
 }
 
 static std::unique_ptr<Module>
-getModuleForFile(LLVMContext &Context, claimed_file &F, raw_fd_ostream *ApiFile,
+getModuleForFile(LLVMContext &Context, claimed_file &F,
+                 off_t Filesize, raw_fd_ostream *ApiFile,
                  StringSet<> &Internalize, StringSet<> &Maybe) {
-  ld_plugin_input_file File;
-  if (get_input_file(F.handle, &File) != LDPS_OK)
-    message(LDPL_FATAL, "Failed to get file information");
 
   if (get_symbols(F.handle, F.syms.size(), &F.syms[0]) != LDPS_OK)
     message(LDPL_FATAL, "Failed to get symbol information");
@@ -558,7 +572,7 @@ getModuleForFile(LLVMContext &Context, claimed_file &F, raw_fd_ostream *ApiFile,
 
   llvm::ErrorOr<MemoryBufferRef> MBOrErr =
       object::IRObjectFile::findBitcodeInMemBuffer(
-          MemoryBufferRef(StringRef((const char *)View, File.filesize), ""));
+          MemoryBufferRef(StringRef((const char *)View, Filesize), ""));
   if (std::error_code EC = MBOrErr.getError())
     message(LDPL_FATAL, "Could not read bitcode from file : %s",
             EC.message().c_str());
@@ -566,9 +580,6 @@ getModuleForFile(LLVMContext &Context, claimed_file &F, raw_fd_ostream *ApiFile,
   std::unique_ptr<MemoryBuffer> Buffer =
       MemoryBuffer::getMemBuffer(MBOrErr->getBuffer(), "", false);
 
-  if (release_input_file(F.handle) != LDPS_OK)
-    message(LDPL_FATAL, "Failed to release file information");
-
   ErrorOr<Module *> MOrErr = getLazyBitcodeModule(std::move(Buffer), Context);
 
   if (std::error_code EC = MOrErr.getError())
@@ -760,6 +771,34 @@ static void codegen(Module &M) {
     Cleanup.push_back(Filename.c_str());
 }
 
+// @LOCALMOD-BEGIN
+static void wrapSymbol(Module *M, const char *sym) {
+  std::string wrapSymName("__wrap_");
+  wrapSymName += sym;
+  std::string realSymName("__real_");
+  realSymName += sym;
+
+  Constant *SymGV = M->getNamedValue(sym);
+
+  // Replace uses of "sym" with "__wrap_sym".
+  if (SymGV) {
+    Constant *WrapGV = M->getNamedValue(wrapSymName);
+    if (!WrapGV)
+      WrapGV = M->getOrInsertGlobal(wrapSymName, SymGV->getType());
+    SymGV->replaceAllUsesWith(
+        ConstantExpr::getBitCast(WrapGV, SymGV->getType()));
+  }
+
+  // Replace uses of "__real_sym" with "sym".
+  if (Constant *RealGV = M->getNamedValue(realSymName)) {
+    if (!SymGV)
+      SymGV = M->getOrInsertGlobal(sym, RealGV->getType());
+    RealGV->replaceAllUsesWith(
+        ConstantExpr::getBitCast(SymGV, RealGV->getType()));
+  }
+}
+// @LOCALMOD-END
+
 /// gold informs us that all symbols have been read. At this point, we use
 /// get_symbols to see if any of our definitions have been overridden by a
 /// native object file. Then, perform optimization and codegen.
@@ -776,8 +815,12 @@ static ld_plugin_status allSymbolsReadHook(raw_fd_ostream *ApiFile) {
   StringSet<> Internalize;
   StringSet<> Maybe;
   for (claimed_file &F : Modules) {
+    ld_plugin_input_file File;
+    if (get_input_file(F.handle, &File) != LDPS_OK)
+      message(LDPL_FATAL, "Failed to get file information");
     std::unique_ptr<Module> M =
-        getModuleForFile(Context, F, ApiFile, Internalize, Maybe);
+        getModuleForFile(Context, F, File.filesize, ApiFile,
+                         Internalize, Maybe);
     if (!options::triple.empty())
       M->setTargetTriple(options::triple.c_str());
     else if (M->getTargetTriple().empty()) {
@@ -786,6 +829,8 @@ static ld_plugin_status allSymbolsReadHook(raw_fd_ostream *ApiFile) {
 
     if (L.linkInModule(M.get()))
       message(LDPL_FATAL, "Failed to link module");
+    if (release_input_file(F.handle) != LDPS_OK)
+      message(LDPL_FATAL, "Failed to release file information");
   }
 
   for (const auto &Name : Internalize) {
@@ -803,6 +848,23 @@ static ld_plugin_status allSymbolsReadHook(raw_fd_ostream *ApiFile) {
       internalize(*GV);
   }
 
+  // @LOCALMOD-BEGIN
+  // Perform symbol wrapping.
+  unsigned num_wrapped;
+  if ((*get_num_wrapped)(&num_wrapped) != LDPS_OK) {
+    (*message)(LDPL_ERROR, "Unable to get the number of wrapped symbols.");
+    return LDPS_ERR;
+  }
+  for (unsigned i = 0; i < num_wrapped; ++i) {
+    const char *sym;
+    if ((*get_wrapped)(i, &sym) != LDPS_OK) {
+      (*message)(LDPL_ERROR, "Unable to wrap symbol %u/%u.", i, num_wrapped);
+      return LDPS_ERR;
+    }
+    wrapSymbol(Combined.get(), sym);
+  }
+  // @LOCALMOD-END
+
   if (options::TheOutputType == options::OT_DISABLE)
     return LDPS_OK;