[clang-cas-test] Support using the CAS plugin mechanism

(cherry picked from commit be12a51)

Author: akyrtzi

clang/test/CAS/print-compile-job-cache-key.c

@@ -58,3 +58,15 @@
 // RUN:   -e "s/\" .*$//" > %t/include-tree-id
 
 // RUN: clang-cas-test -print-include-tree -cas %t/cas @%t/include-tree-id | FileCheck %s -check-prefix=INCLUDE_TREE -DSRC_FILE=%s
+
+// Print key from plugin CAS.
+// RUN: llvm-cas --cas plugin://%llvmshlibdir/libCASPluginTest%pluginext?ondisk-path=%t/cas-plugin --ingest --data %s > %t/casid-plugin
+// RUN: %clang -cc1 -triple x86_64-apple-macos11 \
+// RUN:   -fcas-path %t/cas-plugin -fcas-fs @%t/casid-plugin -fcache-compile-job \
+// RUN:   -fcas-plugin-path %llvmshlibdir/libCASPluginTest%pluginext \
+// RUN:   -Rcompile-job-cache-miss -emit-obj -o %t/output.o %s 2> %t/output-plugin.txt
+// RUN: cat %t/output-plugin.txt | sed \
+// RUN:   -e "s/^.*miss for '//" \
+// RUN:   -e "s/' .*$//" > %t/cache-key-plugin
+// RUN: clang-cas-test -print-compile-job-cache-key -cas %t/cas @%t/cache-key-plugin \
+// RUN:   -fcas-plugin-path %llvmshlibdir/libCASPluginTest%pluginext | FileCheck %s

clang/tools/clang-cas-test/ClangCASTest.cpp

@@ -53,6 +53,11 @@ int main(int Argc, const char **Argv) {
 
   cl::opt<std::string> CASPath("cas", cl::desc("On-disk CAS path"),
                                cl::value_desc("path"));
+  cl::opt<std::string> CASPluginPath("fcas-plugin-path",
+                                     cl::desc("Path to plugin CAS library"),
+                                     cl::value_desc("path"));
+  cl::list<std::string> CASPluginOpts("fcas-plugin-option",
+                                      cl::desc("Plugin CAS Options"));
   cl::list<std::string> Inputs(cl::Positional, cl::desc("<input>..."));
 
   cl::ParseCommandLineOptions(Argc, Argv, "clang-cas-test");
@@ -69,6 +74,13 @@ int main(int Argc, const char **Argv) {
   // Printing a cache key only makes sense in an existing CAS, so default to
   // on-disk instead of in-memory if no --cas path is specified.
   Opts.CASPath = CASPath.empty() ? std::string("auto") : CASPath;
+  if (!CASPluginPath.empty()) {
+    Opts.PluginPath = CASPluginPath;
+    for (const auto &PluginOpt : CASPluginOpts) {
+      auto [Name, Val] = StringRef(PluginOpt).split('=');
+      Opts.PluginOptions.push_back({std::string(Name), std::string(Val)});
+    }
+  }
 
   auto CAS =
       Opts.getOrCreateDatabases(*Diags, /*CreateEmptyCASOnFailure=*/false)

llvm/tools/libCASPluginTest/libCASPluginTest.cpp

@@ -115,12 +115,6 @@ struct CASWrapper {
   /// Load the object, potentially "downloading" it from upstream.
   Expected<std::optional<ondisk::ObjectHandle>> loadObject(ObjectID ID);
 
-  /// "Uploads" the full object node graph.
-  Expected<ObjectID> upstreamNode(ObjectID Node);
-  /// "Downloads" only a single object node. The rest of the nodes in the graph
-  /// will be "downloaded" lazily as they are visited.
-  Expected<ObjectID> downstreamNode(ObjectID Node);
-
   /// "Uploads" a key the associated full node graph.
   Error upstreamKey(ArrayRef<uint8_t> Key, ObjectID Value);
   /// "Downloads" the single root node that is associated with the key. The rest
@@ -133,6 +127,13 @@ struct CASWrapper {
     Fn(errs());
     errs().flush();
   }
+
+private:
+  /// "Uploads" the full object node graph.
+  Expected<ObjectID> upstreamNode(ObjectID Node);
+  /// "Downloads" only a single object node. The rest of the nodes in the graph
+  /// will be "downloaded" lazily as they are visited.
+  Expected<ObjectID> downstreamNode(ObjectID Node);
 };
 
 DEFINE_SIMPLE_CONVERSION_FUNCTIONS(CASWrapper, llcas_cas_t)
@@ -208,6 +209,8 @@ Expected<ObjectID> CASWrapper::downstreamNode(ObjectID Node) {
 }
 
 Error CASWrapper::upstreamKey(ArrayRef<uint8_t> Key, ObjectID Value) {
+  if (!UpstreamDB)
+    return Error::success();
   Expected<ObjectID> UpstreamVal = upstreamNode(Value);
   if (!UpstreamVal)
     return UpstreamVal.takeError();
@@ -220,6 +223,8 @@ Error CASWrapper::upstreamKey(ArrayRef<uint8_t> Key, ObjectID Value) {
 
 Expected<std::optional<ObjectID>>
 CASWrapper::downstreamKey(ArrayRef<uint8_t> Key) {
+  if (!UpstreamDB)
+    return std::nullopt;
   std::optional<ObjectID> UpstreamValue;
   if (Error E = UpstreamDB->KVGet(Key).moveInto(UpstreamValue))
     return std::move(E);