From 27e0d1f3da2e0b7046dacb40794739d739e454a3 Mon Sep 17 00:00:00 2001
From: Calin Juravle <calin@google.com>
Date: Wed, 26 Jul 2017 00:16:07 -0700
Subject: Pass the class loader context to dex2oat when optimizing at runtime

Until now we always passed the special shared library symbol "&" when we
called dex2oat at runtime without an explicit class path.

This CL changes that and passes the class loader context inferred from the
runtime class loaders to dex2oat. If any of the runtime class loaders is
not supported we continue to pass the special library symbol.

Bug: 38138251
Test: m test-art-host
Change-Id: Ica43ee8a3f36dab2d9ed0e634a9f6341379c8e1c
---
 runtime/oat_file_assistant.cc | 31 ++++++++++++++++++++-----------
 1 file changed, 20 insertions(+), 11 deletions(-)

(limited to 'runtime/oat_file_assistant.cc')

diff --git a/runtime/oat_file_assistant.cc b/runtime/oat_file_assistant.cc
index dae41c1b67..3794f51cb7 100644
--- a/runtime/oat_file_assistant.cc
+++ b/runtime/oat_file_assistant.cc
@@ -37,6 +37,7 @@
 #include "scoped_thread_state_change-inl.h"
 #include "utils.h"
 #include "vdex_file.h"
+#include "class_loader_context.h"
 
 namespace art {
 
@@ -225,13 +226,25 @@ bool OatFileAssistant::IsUpToDate() {
 }
 
 OatFileAssistant::ResultOfAttemptToUpdate
-OatFileAssistant::MakeUpToDate(bool profile_changed, std::string* error_msg) {
+OatFileAssistant::MakeUpToDate(bool profile_changed,
+                               const std::string& class_loader_context,
+                               std::string* error_msg) {
   CompilerFilter::Filter target;
   if (!GetRuntimeCompilerFilterOption(&target, error_msg)) {
     return kUpdateNotAttempted;
   }
 
   OatFileInfo& info = GetBestInfo();
+  // TODO(calin, jeffhao): the context should really be passed to GetDexOptNeeded: b/62269291.
+  // This is actually not trivial in the current logic as it will interact with the collision
+  // check:
+  //   - currently, if the context does not match but we have no collisions we still accept the
+  //     oat file.
+  //   - if GetDexOptNeeded would return kDex2OatFromScratch for a context mismatch and we make
+  //     the oat code up to date the collision check becomes useless.
+  //   - however, MakeUpToDate will not always succeed (e.g. for primary apks, or for dex files
+  //     loaded in other processes). So it boils down to how far do we want to complicate
+  //     the logic in order to enable the use of oat files. Maybe its time to try simplify it.
   switch (info.GetDexOptNeeded(target, profile_changed, /*downgrade*/ false)) {
     case kNoDexOptNeeded:
       return kUpdateSucceeded;
@@ -243,7 +256,7 @@ OatFileAssistant::MakeUpToDate(bool profile_changed, std::string* error_msg) {
     case kDex2OatForBootImage:
     case kDex2OatForRelocation:
     case kDex2OatForFilter:
-      return GenerateOatFileNoChecks(info, target, error_msg);
+      return GenerateOatFileNoChecks(info, target, class_loader_context, error_msg);
   }
   UNREACHABLE();
 }
@@ -628,7 +641,10 @@ static bool PrepareOdexDirectories(const std::string& dex_location,
 }
 
 OatFileAssistant::ResultOfAttemptToUpdate OatFileAssistant::GenerateOatFileNoChecks(
-      OatFileAssistant::OatFileInfo& info, CompilerFilter::Filter filter, std::string* error_msg) {
+      OatFileAssistant::OatFileInfo& info,
+      CompilerFilter::Filter filter,
+      const std::string& class_loader_context,
+      std::string* error_msg) {
   CHECK(error_msg != nullptr);
 
   Runtime* runtime = Runtime::Current();
@@ -704,6 +720,7 @@ OatFileAssistant::ResultOfAttemptToUpdate OatFileAssistant::GenerateOatFileNoChe
   args.push_back("--oat-fd=" + std::to_string(oat_file->Fd()));
   args.push_back("--oat-location=" + oat_file_name);
   args.push_back("--compiler-filter=" + CompilerFilter::NameOfFilter(filter));
+  args.push_back("--class-loader-context=" + class_loader_context);
 
   if (!Dex2Oat(args, error_msg)) {
     // Manually delete the oat and vdex files. This ensures there is no garbage
@@ -743,14 +760,6 @@ bool OatFileAssistant::Dex2Oat(const std::vector<std::string>& args,
 
   std::vector<std::string> argv;
   argv.push_back(runtime->GetCompilerExecutable());
-  argv.push_back("--runtime-arg");
-  argv.push_back("-classpath");
-  argv.push_back("--runtime-arg");
-  std::string class_path = runtime->GetClassPathString();
-  if (class_path == "") {
-    class_path = OatFile::kSpecialSharedLibrary;
-  }
-  argv.push_back(class_path);
   if (runtime->IsJavaDebuggable()) {
     argv.push_back("--debuggable");
   }
-- 
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