commit f0acfe7a812a332122011832074142718c278dae
author Nicolas Geoffray <ngeoffray@google.com> Mon Jan 09 20:54:52 2017 +0000
committer Nicolas Geoffray <ngeoffray@google.com> Tue Jan 10 21:26:23 2017 +0000
tree 49c4fc481cebd03323aaf0109066859165508303
parent 91db41f315f6c2366b7098c531224bee01170364

Keep resolved String in HLoadString.

For the following reasons:
- Avoids needing to do a lookup again in CodeGenerator::EmitJitRoots.
- Fixes races where we the string was GC'ed before CodeGenerator::EmitJitRoots.
- Makes it possible to do GVN on the same string but defined in different
  dex files.

Test: test-art-host, test-art-target
Change-Id: If2b5d3079f7555427b1b96ab04546b3373fcf921

compiler/optimizing/code_generator_arm.cc

diff --git a/compiler/optimizing/code_generator_arm.cc b/compiler/optimizing/code_generator_arm.cc
index 8a7f6d3..3009103 100644
--- a/compiler/optimizing/code_generator_arm.cc
+++ b/compiler/optimizing/code_generator_arm.cc
@@ -5937,7 +5937,9 @@
   }
 }
 
-void InstructionCodeGeneratorARM::VisitLoadString(HLoadString* load) {
+// NO_THREAD_SAFETY_ANALYSIS as we manipulate handles whose internal object we know does not
+// move.
+void InstructionCodeGeneratorARM::VisitLoadString(HLoadString* load) NO_THREAD_SAFETY_ANALYSIS {
   LocationSummary* locations = load->GetLocations();
   Location out_loc = locations->Out();
   Register out = out_loc.AsRegister<Register>();
@@ -5962,8 +5964,9 @@
       return;  // No dex cache slow path.
     }
     case HLoadString::LoadKind::kBootImageAddress: {
-      DCHECK_NE(load->GetAddress(), 0u);
-      uint32_t address = dchecked_integral_cast<uint32_t>(load->GetAddress());
+      uint32_t address = dchecked_integral_cast<uint32_t>(
+          reinterpret_cast<uintptr_t>(load->GetString().Get()));
+      DCHECK_NE(address, 0u);
       __ LoadLiteral(out, codegen_->DeduplicateBootImageAddressLiteral(address));
       return;  // No dex cache slow path.
     }
@@ -5987,7 +5990,8 @@
     }
     case HLoadString::LoadKind::kJitTableAddress: {
       __ LoadLiteral(out, codegen_->DeduplicateJitStringLiteral(load->GetDexFile(),
-                                                                load->GetStringIndex()));
+                                                                load->GetStringIndex(),
+                                                                load->GetString()));
       // /* GcRoot<mirror::String> */ out = *out
       GenerateGcRootFieldLoad(load, out_loc, out, /* offset */ 0, kCompilerReadBarrierOption);
       return;
@@ -7317,8 +7321,10 @@
 }
 
 Literal* CodeGeneratorARM::DeduplicateJitStringLiteral(const DexFile& dex_file,
-                                                       dex::StringIndex string_index) {
-  jit_string_roots_.Overwrite(StringReference(&dex_file, string_index), /* placeholder */ 0u);
+                                                       dex::StringIndex string_index,
+                                                       Handle<mirror::String> handle) {
+  jit_string_roots_.Overwrite(StringReference(&dex_file, string_index),
+                              reinterpret_cast64<uint64_t>(handle.GetReference()));
   return jit_string_patches_.GetOrCreate(
       StringReference(&dex_file, string_index),
       [this]() { return __ NewLiteral<uint32_t>(/* placeholder */ 0u); });