[CAS] Add an utility action to swift-cache-tool to print cache key

Add an utility action to print information contained in the swift
compile cache key. This is useful to figure out why cache key is
different.

Author: cachemeifyoucan

include/swift/Frontend/CompileJobCacheKey.h

@@ -23,6 +23,7 @@
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/CAS/ObjectStore.h"
 #include "llvm/Support/Error.h"
+#include "llvm/Support/raw_ostream.h"
 
 namespace swift {
 
@@ -43,6 +44,11 @@ llvm::Expected<llvm::cas::ObjectRef>
 createCompileJobCacheKeyForOutput(llvm::cas::ObjectStore &CAS,
                                   llvm::cas::ObjectRef BaseKey,
                                   unsigned InputIndex);
+
+/// Print the CompileJobKey for debugging purpose.
+llvm::Error printCompileJobCacheKey(llvm::cas::ObjectStore &CAS,
+                                    llvm::cas::ObjectRef Key,
+                                    llvm::raw_ostream &os);
 } // namespace swift
 
 #endif

lib/DriverTool/swift_cache_tool_main.cpp

@@ -48,6 +48,7 @@ enum class SwiftCacheToolAction {
   ValidateOutputs,
   RenderDiags,
   PrintIncludeTreeList,
+  PrintCompileCacheKey,
 };
 
 struct OutputEntry {
@@ -146,12 +147,15 @@ class SwiftCacheToolInvocation {
               .Case("render-diags", SwiftCacheToolAction::RenderDiags)
               .Case("print-include-tree-list",
                     SwiftCacheToolAction::PrintIncludeTreeList)
+              .Case("print-compile-cache-key",
+                    SwiftCacheToolAction::PrintCompileCacheKey)
               .Default(SwiftCacheToolAction::Invalid);
 
     if (ActionKind == SwiftCacheToolAction::Invalid) {
       llvm::errs()
           << "Invalid option specified for -cache-tool-action: "
-          << "print-base-key|print-output-keys|validate-outputs|render-diags\n";
+          << "print-base-key|print-output-keys|validate-outputs|render-diags|"
+          << "print-include-tree-list|print-compile-cache-key\n";
       return 1;
     }
 
@@ -170,6 +174,8 @@ class SwiftCacheToolInvocation {
       return renderDiags();
     case SwiftCacheToolAction::PrintIncludeTreeList:
       return printIncludeTreeList();
+    case SwiftCacheToolAction::PrintCompileCacheKey:
+      return printCompileCacheKey();
     case SwiftCacheToolAction::Invalid:
       return 0; // No action. Probably just print help. Return.
     }
@@ -271,6 +277,7 @@ class SwiftCacheToolInvocation {
   int validateOutputs();
   int renderDiags();
   int printIncludeTreeList();
+  int printCompileCacheKey();
 };
 
 } // end anonymous namespace
@@ -522,6 +529,38 @@ int SwiftCacheToolInvocation::printIncludeTreeList() {
   return 0;
 }
 
+int SwiftCacheToolInvocation::printCompileCacheKey() {
+  auto error = [](llvm::Error err) {
+    llvm::errs() << "cannot print cache key: " << llvm::toString(std::move(err))
+                 << "\n";
+    return 1;
+  };
+  if (Inputs.size() != 1) {
+    llvm::errs() << "expect 1 CASID as input\n";
+    return 1;
+  }
+  auto DB = CASOpts.getOrCreateDatabases();
+  if (!DB) {
+    return error(DB.takeError());
+  }
+  auto CAS = DB->first;
+  auto &input = Inputs.front();
+  auto ID = CAS->parseID(input);
+  if (!ID)
+    return error(ID.takeError());
+
+  auto Ref = CAS->getReference(*ID);
+  if (!Ref) {
+    llvm::errs() << "CAS object not found: " << input << "\n";
+    return 1;
+  }
+
+  if (auto err = swift::printCompileJobCacheKey(*CAS, *Ref, llvm::outs()))
+    return error(std::move(err));
+
+  return 0;
+}
+
 int swift_cache_tool_main(ArrayRef<const char *> Args, const char *Argv0,
                           void *MainAddr) {
   INITIALIZE_LLVM();

lib/Frontend/CompileJobCacheKey.cpp

@@ -15,17 +15,21 @@
 //===----------------------------------------------------------------------===//
 
 #include "swift/Option/Options.h"
-#include <swift/Frontend/CompileJobCacheKey.h>
-#include <swift/Basic/Version.h>
-#include <llvm/ADT/SmallString.h>
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/CAS/HierarchicalTreeBuilder.h"
 #include "llvm/CAS/ObjectStore.h"
+#include "llvm/CAS/TreeEntry.h"
+#include "llvm/CAS/TreeSchema.h"
 #include "llvm/Option/ArgList.h"
 #include "llvm/Option/OptTable.h"
+#include "llvm/Support/Endian.h"
 #include "llvm/Support/EndianStream.h"
 #include "llvm/Support/Error.h"
 #include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/raw_ostream.h"
+#include <llvm/ADT/SmallString.h>
+#include <swift/Basic/Version.h>
+#include <swift/Frontend/CompileJobCacheKey.h>
 
 using namespace swift;
 
@@ -99,3 +103,52 @@ swift::createCompileJobCacheKeyForOutput(llvm::cas::ObjectStore &CAS,
 
   return CAS.storeFromString({BaseKey}, OS.str());
 }
+
+llvm::Error swift::printCompileJobCacheKey(llvm::cas::ObjectStore &CAS,
+                                           llvm::cas::ObjectRef Key,
+                                           llvm::raw_ostream &OS) {
+  auto Proxy = CAS.getProxy(Key);
+  if (!Proxy)
+    return Proxy.takeError();
+
+  if (Proxy->getData().size() != sizeof(uint32_t))
+    return llvm::createStringError("incorrect size for cache key node");
+  if (Proxy->getNumReferences() != 1)
+    return llvm::createStringError("incorrect child number for cache key node");
+
+  uint32_t InputIndex = llvm::support::endian::read<uint32_t>(
+      Proxy->getData().data(), llvm::endianness::little);
+
+  auto Base = Proxy->getReference(0);
+  llvm::cas::TreeSchema Schema(CAS);
+  auto Tree = Schema.load(Base);
+  if (!Tree)
+    return Tree.takeError();
+
+  std::string BaseStr;
+  llvm::raw_string_ostream BaseOS(BaseStr);
+  auto Err = Tree->forEachEntry(
+      [&](const llvm::cas::NamedTreeEntry &Entry) -> llvm::Error {
+        auto Ref = Entry.getRef();
+        auto DataProxy = CAS.getProxy(Ref);
+        if (!DataProxy)
+          return DataProxy.takeError();
+
+        BaseOS.indent(2) << Entry.getName() << "\n";
+        StringRef Line, Remain = DataProxy->getData();
+        while (!Remain.empty()) {
+          std::tie(Line, Remain) = Remain.split(0);
+          BaseOS.indent(4) << Line << "\n";
+        }
+        return llvm::Error::success();
+      });
+  if (Err)
+    return Err;
+
+  llvm::outs() << "Cache Key " << CAS.getID(Key).toString() << "\n";
+  llvm::outs() << "Swift Compiler Invocation Info:\n";
+  llvm::outs() << BaseStr;
+  llvm::outs() << "Input index: " << InputIndex << "\n";
+
+  return llvm::Error::success();
+}

test/CAS/cas-explicit-module-map.swift

@@ -31,6 +31,12 @@
 // RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import -parse-stdlib @%t/MyApp.cmd > %t/keys.json
 // RUN: %{python} %S/Inputs/ExtractOutputKey.py %t/keys.json %t/Test.swift > %t/key
 
+// RUN: %cache-tool -cas-path %t/cas -cache-tool-action print-compile-cache-key @%t/key | %FileCheck %s --check-prefix=CACHE-KEY
+// CACHE-KEY: Cache Key llvmcas://
+// CACHE-KEY-NEXT: Swift Compiler Invocation Info:
+// CACHE-KEY-NEXT: command-line
+// CACHE-KEY: Input index: 0
+
 // RUN: %target-swift-frontend -typecheck-module-from-interface %t/Foo.swiftinterface -disable-implicit-swift-modules \
 // RUN:   -module-cache-path %t.module-cache -explicit-swift-module-map-file @%t/map.casid  \
 // RUN:   -cache-compile-job -cas-path %t/cas -swift-version 5 -enable-library-evolution \