Update GetDexOptNeeded to handle different levels of compilation

extract-only or profile-guide oat files are considered up to date from
runtime perspective as they don't necessary need (re)compilation or
relocation. However, it is useful to return a more refined code to the
caller so that they can decide whether or not that's good enough.

For example, the package manager might decide to still compile a
previous extract-only and during profile guide compilation we should
always recompile even if we have an oat file.

Note that dex files compiled via ClassLoaders will still be fully
compiled.

This change introduces:
- a new key in the oat header kCompilationType to capture what type of
compilation has been made. Note tha the key might be missing. The
distinction is needed in order to avoid recompilation of a previous
fully compiled file during profile guide compilation analysis.
- a new argument to GetDexOptNeeded which tells the runtime to cast its
opinion whether or not the oat file is up to date relative to the
desired target type of compilation.

Bug: 27189430

(cherry picked from commit d91b8a2464b99625efe03caf7d30c8372bc378ed)

Change-Id: I6ce450350f388451f7bab7d285c1846d539a4b13

1 files changed, 8 insertions, 18 deletions

diff --git a/dex2oat/dex2oat.cc b/dex2oat/dex2oat.cc
index d9a2f300d9..cbce0f6e91 100644
--- a/dex2oat/dex2oat.cc
+++ b/dex2oat/dex2oat.cc
@@ -1031,9 +1031,11 @@ class Dex2Oat FINAL {
     key_value_store_->Put(
         OatHeader::kDebuggableKey,
         compiler_options_->debuggable_ ? OatHeader::kTrueValue : OatHeader::kFalseValue);
-    key_value_store_->Put(
-        OatHeader::kExtractOnlyKey,
-        compiler_options_->IsExtractOnly() ? OatHeader::kTrueValue : OatHeader::kFalseValue);
+    if (compiler_options_->IsExtractOnly()) {
+      key_value_store_->Put(OatHeader::kCompilationType, OatHeader::kExtractOnlyValue);
+    } else if (UseProfileGuidedCompilation()) {
+      key_value_store_->Put(OatHeader::kCompilationType, OatHeader::kProfileGuideCompiledValue);
+    }
   }
 
   // Parse the arguments from the command line. In case of an unrecognized option or impossible
@@ -1888,13 +1890,6 @@ class Dex2Oat FINAL {
     return success;
   }
 
-  bool ShouldCompileBasedOnProfiles() const {
-    DCHECK(UseProfileGuidedCompilation());
-    // If we are given a profile, compile only if we have some data in it.
-    return (profile_compilation_info_ != nullptr) &&
-        (profile_compilation_info_->GetNumberOfMethods() != 0);
-  }
-
  private:
   template <typename T>
   static std::vector<T*> MakeNonOwningPointerVector(const std::vector<std::unique_ptr<T>>& src) {
@@ -2590,16 +2585,11 @@ static int dex2oat(int argc, char** argv) {
   // Parse arguments. Argument mistakes will lead to exit(EXIT_FAILURE) in UsageError.
   dex2oat->ParseArgs(argc, argv);
 
-  // Process profile information and assess if we need to do a profile guided compilation.
+  // If needed, process profile information for profile guided compilation.
   // This operation involves I/O.
   if (dex2oat->UseProfileGuidedCompilation()) {
-    if (dex2oat->LoadProfile()) {
-      if (!dex2oat->ShouldCompileBasedOnProfiles()) {
-        LOG(INFO) << "Skipped compilation because of insignificant profile delta";
-        return EXIT_SUCCESS;
-      }
-    } else {
-      LOG(WARNING) << "Failed to process profile files";
+    if (!dex2oat->LoadProfile()) {
+      LOG(ERROR) << "Failed to process profile file";
       return EXIT_FAILURE;
     }
   }