LTO: Simplify caching interface.

The NativeObjectOutput class has a design problem: it mixes up the caching
policy with the interface for output streams, which makes the client-side
code hard to follow and would for example make it harder to replace the
cache implementation in an arbitrary client.

This change separates the two aspects by moving the caching policy
to a separate field in Config, replacing NativeObjectOutput with a
NativeObjectStream class which only deals with streams and does not need to
be overridden by most clients and introducing an AddFile callback for adding
files (e.g. from the cache) to the link.

Differential Revision: https://reviews.llvm.org/D24622

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@282299 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 18 insertions, 30 deletions

diff --git a/tools/gold/gold-plugin.cpp b/tools/gold/gold-plugin.cpp
index 34696ba16a97..9bdc7abc5b4f 100644
--- a/tools/gold/gold-plugin.cpp
+++ b/tools/gold/gold-plugin.cpp
@@ -675,24 +675,6 @@ static void getThinLTOOldAndNewPrefix(std::string &OldPrefix,
   NewPrefix = Split.second.str();
 }
 
-namespace {
-// Define the LTOOutput handling
-class LTOOutput : public lto::NativeObjectOutput {
-  StringRef Path;
-
-public:
-  LTOOutput(StringRef Path) : Path(Path) {}
-  // Open the filename \p Path and allocate a stream.
-  std::unique_ptr<raw_pwrite_stream> getStream() override {
-    int FD;
-    std::error_code EC = sys::fs::openFileForWrite(Path, FD, sys::fs::F_None);
-    if (EC)
-      message(LDPL_FATAL, "Could not open file: %s", EC.message().c_str());
-    return llvm::make_unique<llvm::raw_fd_ostream>(FD, true);
-  }
-};
-}
-
 static std::unique_ptr<LTO> createLTO() {
   Config Conf;
   ThinBackend Backend;
@@ -831,21 +813,27 @@ static ld_plugin_status allSymbolsReadHook() {
   std::vector<uintptr_t> IsTemporary(MaxTasks);
   std::vector<SmallString<128>> Filenames(MaxTasks);
 
-  auto AddOutput =
-      [&](size_t Task) -> std::unique_ptr<lto::NativeObjectOutput> {
-    auto &OutputName = Filenames[Task];
-    getOutputFileName(Filename, /*TempOutFile=*/!SaveTemps, OutputName,
+  auto AddStream =
+      [&](size_t Task) -> std::unique_ptr<lto::NativeObjectStream> {
+    IsTemporary[Task] = !SaveTemps;
+    getOutputFileName(Filename, /*TempOutFile=*/!SaveTemps, Filenames[Task],
                       MaxTasks > 1 ? Task : -1);
-    IsTemporary[Task] = !SaveTemps && options::cache_dir.empty();
-    if (options::cache_dir.empty())
-      return llvm::make_unique<LTOOutput>(OutputName);
-
-    return llvm::make_unique<CacheObjectOutput>(
-        options::cache_dir,
-        [&OutputName](std::string EntryPath) { OutputName = EntryPath; });
+    int FD;
+    std::error_code EC =
+        sys::fs::openFileForWrite(Filenames[Task], FD, sys::fs::F_None);
+    if (EC)
+      message(LDPL_FATAL, "Could not open file: %s", EC.message().c_str());
+    return llvm::make_unique<lto::NativeObjectStream>(
+        llvm::make_unique<llvm::raw_fd_ostream>(FD, true));
   };
 
-  check(Lto->run(AddOutput));
+  auto AddFile = [&](size_t Task, StringRef Path) { Filenames[Task] = Path; };
+
+  NativeObjectCache Cache;
+  if (!options::cache_dir.empty())
+    Cache = localCache(options::cache_dir, AddFile);
+
+  check(Lto->run(AddStream, Cache));
 
   if (options::TheOutputType == options::OT_DISABLE ||
       options::TheOutputType == options::OT_BC_ONLY)