Visit deoptimized shadow frames as roots
During deoptimization, we create shadow frames but do not attach them to the
stack until we transition to interpreter mode. If a GC happens before that,
these shadow frames are not visited by GC so they may contain stale references.
This CL addresses this issue by visiting the shadow frames "under contruction"
in Thread::VisitRoots so we correctly update all references they hold.
To make them visible, we now save the top shadow frame (the first one created)
in the field Thread::tls_ptr_sized_values::deoptimization_shadow_frame. This
field will then be cleared when transitioning to interpreter mode.
Bug: 14324885
Change-Id: Ib213ddc80f19cfcdfcec6f20acaa7f1a0e9ce2c1
diff --git a/runtime/thread.cc b/runtime/thread.cc
index 095404f..2a7cfff 100644
--- a/runtime/thread.cc
+++ b/runtime/thread.cc
@@ -1931,92 +1931,102 @@
bool VisitFrame() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
if (false) {
LOG(INFO) << "Visiting stack roots in " << PrettyMethod(GetMethod())
- << StringPrintf("@ PC:%04x", GetDexPc());
+ << StringPrintf("@ PC:%04x", GetDexPc());
}
ShadowFrame* shadow_frame = GetCurrentShadowFrame();
if (shadow_frame != nullptr) {
- mirror::ArtMethod* m = shadow_frame->GetMethod();
- size_t num_regs = shadow_frame->NumberOfVRegs();
- if (m->IsNative() || shadow_frame->HasReferenceArray()) {
- // SIRT for JNI or References for interpreter.
- for (size_t reg = 0; reg < num_regs; ++reg) {
+ VisitShadowFrame(shadow_frame);
+ } else {
+ VisitQuickFrame();
+ }
+ return true;
+ }
+
+ void VisitShadowFrame(ShadowFrame* shadow_frame) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
+ mirror::ArtMethod* m = shadow_frame->GetMethod();
+ size_t num_regs = shadow_frame->NumberOfVRegs();
+ if (m->IsNative() || shadow_frame->HasReferenceArray()) {
+ // SIRT for JNI or References for interpreter.
+ for (size_t reg = 0; reg < num_regs; ++reg) {
+ mirror::Object* ref = shadow_frame->GetVRegReference(reg);
+ if (ref != nullptr) {
+ mirror::Object* new_ref = ref;
+ visitor_(&new_ref, reg, this);
+ if (new_ref != ref) {
+ shadow_frame->SetVRegReference(reg, new_ref);
+ }
+ }
+ }
+ } else {
+ // Java method.
+ // Portable path use DexGcMap and store in Method.native_gc_map_.
+ const uint8_t* gc_map = m->GetNativeGcMap();
+ CHECK(gc_map != nullptr) << PrettyMethod(m);
+ verifier::DexPcToReferenceMap dex_gc_map(gc_map);
+ uint32_t dex_pc = shadow_frame->GetDexPC();
+ const uint8_t* reg_bitmap = dex_gc_map.FindBitMap(dex_pc);
+ DCHECK(reg_bitmap != nullptr);
+ num_regs = std::min(dex_gc_map.RegWidth() * 8, num_regs);
+ for (size_t reg = 0; reg < num_regs; ++reg) {
+ if (TestBitmap(reg, reg_bitmap)) {
mirror::Object* ref = shadow_frame->GetVRegReference(reg);
if (ref != nullptr) {
mirror::Object* new_ref = ref;
visitor_(&new_ref, reg, this);
if (new_ref != ref) {
- shadow_frame->SetVRegReference(reg, new_ref);
- }
- }
- }
- } else {
- // Java method.
- // Portable path use DexGcMap and store in Method.native_gc_map_.
- const uint8_t* gc_map = m->GetNativeGcMap();
- CHECK(gc_map != nullptr) << PrettyMethod(m);
- verifier::DexPcToReferenceMap dex_gc_map(gc_map);
- uint32_t dex_pc = GetDexPc();
- const uint8_t* reg_bitmap = dex_gc_map.FindBitMap(dex_pc);
- DCHECK(reg_bitmap != nullptr);
- num_regs = std::min(dex_gc_map.RegWidth() * 8, num_regs);
- for (size_t reg = 0; reg < num_regs; ++reg) {
- if (TestBitmap(reg, reg_bitmap)) {
- mirror::Object* ref = shadow_frame->GetVRegReference(reg);
- if (ref != nullptr) {
- mirror::Object* new_ref = ref;
- visitor_(&new_ref, reg, this);
- if (new_ref != ref) {
- shadow_frame->SetVRegReference(reg, new_ref);
- }
+ shadow_frame->SetVRegReference(reg, new_ref);
}
}
}
}
- } else {
- mirror::ArtMethod* m = GetMethod();
- // Process register map (which native and runtime methods don't have)
- if (!m->IsNative() && !m->IsRuntimeMethod() && !m->IsProxyMethod()) {
- const uint8_t* native_gc_map = m->GetNativeGcMap();
- CHECK(native_gc_map != nullptr) << PrettyMethod(m);
- mh_.ChangeMethod(m);
- const DexFile::CodeItem* code_item = mh_.GetCodeItem();
- DCHECK(code_item != nullptr) << PrettyMethod(m); // Can't be nullptr or how would we compile its instructions?
- NativePcOffsetToReferenceMap map(native_gc_map);
- size_t num_regs = std::min(map.RegWidth() * 8,
- static_cast<size_t>(code_item->registers_size_));
- if (num_regs > 0) {
- const uint8_t* reg_bitmap = map.FindBitMap(GetNativePcOffset());
- DCHECK(reg_bitmap != nullptr);
- const VmapTable vmap_table(m->GetVmapTable());
- uint32_t core_spills = m->GetCoreSpillMask();
- uint32_t fp_spills = m->GetFpSpillMask();
- size_t frame_size = m->GetFrameSizeInBytes();
- // For all dex registers in the bitmap
- mirror::ArtMethod** cur_quick_frame = GetCurrentQuickFrame();
- DCHECK(cur_quick_frame != nullptr);
- for (size_t reg = 0; reg < num_regs; ++reg) {
- // Does this register hold a reference?
- if (TestBitmap(reg, reg_bitmap)) {
- uint32_t vmap_offset;
- if (vmap_table.IsInContext(reg, kReferenceVReg, &vmap_offset)) {
- int vmap_reg = vmap_table.ComputeRegister(core_spills, vmap_offset, kReferenceVReg);
- // This is sound as spilled GPRs will be word sized (ie 32 or 64bit).
- mirror::Object** ref_addr = reinterpret_cast<mirror::Object**>(GetGPRAddress(vmap_reg));
- if (*ref_addr != nullptr) {
- visitor_(ref_addr, reg, this);
- }
- } else {
- StackReference<mirror::Object>* ref_addr =
- reinterpret_cast<StackReference<mirror::Object>*>(
- GetVRegAddr(cur_quick_frame, code_item, core_spills, fp_spills, frame_size,
- reg));
- mirror::Object* ref = ref_addr->AsMirrorPtr();
- if (ref != nullptr) {
- mirror::Object* new_ref = ref;
- visitor_(&new_ref, reg, this);
- if (ref != new_ref) {
- ref_addr->Assign(new_ref);
- }
+ }
+ }
+
+ private:
+ void VisitQuickFrame() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
+ mirror::ArtMethod* m = GetMethod();
+ // Process register map (which native and runtime methods don't have)
+ if (!m->IsNative() && !m->IsRuntimeMethod() && !m->IsProxyMethod()) {
+ const uint8_t* native_gc_map = m->GetNativeGcMap();
+ CHECK(native_gc_map != nullptr) << PrettyMethod(m);
+ mh_.ChangeMethod(m);
+ const DexFile::CodeItem* code_item = mh_.GetCodeItem();
+ DCHECK(code_item != nullptr) << PrettyMethod(m); // Can't be nullptr or how would we compile its instructions?
+ NativePcOffsetToReferenceMap map(native_gc_map);
+ size_t num_regs = std::min(map.RegWidth() * 8,
+ static_cast<size_t>(code_item->registers_size_));
+ if (num_regs > 0) {
+ const uint8_t* reg_bitmap = map.FindBitMap(GetNativePcOffset());
+ DCHECK(reg_bitmap != nullptr);
+ const VmapTable vmap_table(m->GetVmapTable());
+ uint32_t core_spills = m->GetCoreSpillMask();
+ uint32_t fp_spills = m->GetFpSpillMask();
+ size_t frame_size = m->GetFrameSizeInBytes();
+ // For all dex registers in the bitmap
+ mirror::ArtMethod** cur_quick_frame = GetCurrentQuickFrame();
+ DCHECK(cur_quick_frame != nullptr);
+ for (size_t reg = 0; reg < num_regs; ++reg) {
+ // Does this register hold a reference?
+ if (TestBitmap(reg, reg_bitmap)) {
+ uint32_t vmap_offset;
+ if (vmap_table.IsInContext(reg, kReferenceVReg, &vmap_offset)) {
+ int vmap_reg = vmap_table.ComputeRegister(core_spills, vmap_offset, kReferenceVReg);
+ // This is sound as spilled GPRs will be word sized (ie 32 or 64bit).
+ mirror::Object** ref_addr = reinterpret_cast<mirror::Object**>(GetGPRAddress(vmap_reg));
+ if (*ref_addr != nullptr) {
+ visitor_(ref_addr, reg, this);
+ }
+ } else {
+ StackReference<mirror::Object>* ref_addr =
+ reinterpret_cast<StackReference<mirror::Object>*>(
+ GetVRegAddr(cur_quick_frame, code_item, core_spills, fp_spills, frame_size,
+ reg));
+ mirror::Object* ref = ref_addr->AsMirrorPtr();
+ if (ref != nullptr) {
+ mirror::Object* new_ref = ref;
+ visitor_(&new_ref, reg, this);
+ if (ref != new_ref) {
+ ref_addr->Assign(new_ref);
}
}
}
@@ -2024,10 +2034,8 @@
}
}
}
- return true;
}
- private:
static bool TestBitmap(size_t reg, const uint8_t* reg_vector) {
return ((reg_vector[reg / kBitsPerByte] >> (reg % kBitsPerByte)) & 0x01) != 0;
}
@@ -2084,6 +2092,14 @@
if (tlsPtr_.single_step_control != nullptr) {
tlsPtr_.single_step_control->VisitRoots(visitor, arg, thread_id, kRootDebugger);
}
+ if (tlsPtr_.deoptimization_shadow_frame != nullptr) {
+ RootCallbackVisitor visitorToCallback(visitor, arg, thread_id);
+ ReferenceMapVisitor<RootCallbackVisitor> mapper(this, nullptr, visitorToCallback);
+ for (ShadowFrame* shadow_frame = tlsPtr_.deoptimization_shadow_frame; shadow_frame != nullptr;
+ shadow_frame = shadow_frame->GetLink()) {
+ mapper.VisitShadowFrame(shadow_frame);
+ }
+ }
// Visit roots on this thread's stack
Context* context = GetLongJumpContext();
RootCallbackVisitor visitorToCallback(visitor, arg, thread_id);