JIT root tables.

Implement root tables for the JIT. Each JIT compiled method
gets a table allocated before the stack maps.

The table gets visited through Runtime::SweepSystemWeaks.

Implement String roots for x86_64 as an example.

Test: test-art-host test-art-target

Change-Id: Id3d5bc67479e08b52dd4b253e970201203a0f0d2

1 files changed, 25 insertions, 0 deletions

diff --git a/compiler/optimizing/code_generator.h b/compiler/optimizing/code_generator.h
index a81f24e3d8..212d5711f7 100644
--- a/compiler/optimizing/code_generator.h
+++ b/compiler/optimizing/code_generator.h
@@ -31,6 +31,7 @@
 #include "nodes.h"
 #include "optimizing_compiler_stats.h"
 #include "stack_map_stream.h"
+#include "string_reference.h"
 #include "utils/label.h"
 
 namespace art {
@@ -331,6 +332,17 @@ class CodeGenerator : public DeletableArenaObject<kArenaAllocCodeGenerator> {
 
   void BuildStackMaps(MemoryRegion region, const DexFile::CodeItem& code_item);
   size_t ComputeStackMapsSize();
+  size_t GetNumberOfJitRoots() const {
+    return jit_string_roots_.size();
+  }
+
+  // Fills the `literals` array with literals collected during code generation.
+  // Also emits literal patches.
+  void EmitJitRoots(uint8_t* code,
+                    Handle<mirror::ObjectArray<mirror::Object>> roots,
+                    const uint8_t* roots_data,
+                    Handle<mirror::DexCache> outer_dex_cache)
+      REQUIRES_SHARED(Locks::mutator_lock_);
 
   bool IsLeafMethod() const {
     return is_leaf_;
@@ -567,6 +579,8 @@ class CodeGenerator : public DeletableArenaObject<kArenaAllocCodeGenerator> {
         fpu_callee_save_mask_(fpu_callee_save_mask),
         stack_map_stream_(graph->GetArena()),
         block_order_(nullptr),
+        jit_string_roots_(StringReferenceValueComparator(),
+                          graph->GetArena()->Adapter(kArenaAllocCodeGenerator)),
         disasm_info_(nullptr),
         stats_(stats),
         graph_(graph),
@@ -633,6 +647,12 @@ class CodeGenerator : public DeletableArenaObject<kArenaAllocCodeGenerator> {
     return current_slow_path_;
   }
 
+  // Emit the patches assocatied with JIT roots. Only applies to JIT compiled code.
+  virtual void EmitJitRootPatches(uint8_t* code ATTRIBUTE_UNUSED,
+                                  const uint8_t* roots_data ATTRIBUTE_UNUSED) {
+    DCHECK_EQ(jit_string_roots_.size(), 0u);
+  }
+
   // Frame size required for this method.
   uint32_t frame_size_;
   uint32_t core_spill_mask_;
@@ -658,6 +678,11 @@ class CodeGenerator : public DeletableArenaObject<kArenaAllocCodeGenerator> {
   // The order to use for code generation.
   const ArenaVector<HBasicBlock*>* block_order_;
 
+  // Maps a StringReference (dex_file, string_index) to the index in the literal table.
+  // Entries are intially added with a 0 index, and `EmitJitRoots` will compute all the
+  // indices.
+  ArenaSafeMap<StringReference, size_t, StringReferenceValueComparator> jit_string_roots_;
+
   DisassemblyInformation* disasm_info_;
 
  private: