Stop interpreter from accessing code items of compiled code.
The ArtInterpreterToCompiledCodeBridge accesses the code item in a
number of places to handle argument marshalling. However, the code item
of a compiled method should have no need to be accessed by the runtime
at all, since the code has been compiled. By removing these accesses,
there is a drop in the memory footprint of the dex file, since these
code items remain untouched by the runtime.
Maps Vdex Memory Usage: 19.4/33.4MB -> 18.8/33.4MB
Bug: 35800981
Test: mm test-art-host
Change-Id: I147a9267ec022547b384374e1449d20bcab1ead2
diff --git a/runtime/common_dex_operations.h b/runtime/common_dex_operations.h
index 6693eef..8776061 100644
--- a/runtime/common_dex_operations.h
+++ b/runtime/common_dex_operations.h
@@ -36,8 +36,8 @@
void ArtInterpreterToCompiledCodeBridge(Thread* self,
ArtMethod* caller,
- const DexFile::CodeItem* code_item,
ShadowFrame* shadow_frame,
+ uint16_t arg_offset,
JValue* result);
} // namespace interpreter
@@ -56,7 +56,7 @@
interpreter::ArtInterpreterToInterpreterBridge(self, code_item, callee_frame, result);
} else {
interpreter::ArtInterpreterToCompiledCodeBridge(
- self, caller_method, code_item, callee_frame, result);
+ self, caller_method, callee_frame, first_dest_reg, result);
}
} else {
interpreter::UnstartedRuntime::Invoke(self, code_item, callee_frame, result, first_dest_reg);
diff --git a/runtime/interpreter/interpreter.cc b/runtime/interpreter/interpreter.cc
index bf49e84..f3ca338 100644
--- a/runtime/interpreter/interpreter.cc
+++ b/runtime/interpreter/interpreter.cc
@@ -264,7 +264,11 @@
// Pop the shadow frame before calling into compiled code.
self->PopShadowFrame();
- ArtInterpreterToCompiledCodeBridge(self, nullptr, code_item, &shadow_frame, &result);
+ // Calculate the offset of the first input reg. The input registers are in the high regs.
+ // The frame may only contain room for the inputs, in which case the arg offset is 0.
+ uint16_t arg_offset = code_item->registers_size_ == shadow_frame.NumberOfVRegs() ?
+ code_item->registers_size_ - code_item->ins_size_ : 0;
+ ArtInterpreterToCompiledCodeBridge(self, nullptr, &shadow_frame, arg_offset, &result);
// Push the shadow frame back as the caller will expect it.
self->PushShadowFrame(&shadow_frame);
diff --git a/runtime/interpreter/interpreter_common.cc b/runtime/interpreter/interpreter_common.cc
index ef0ddb3..d8c17f2 100644
--- a/runtime/interpreter/interpreter_common.cc
+++ b/runtime/interpreter/interpreter_common.cc
@@ -458,8 +458,8 @@
void ArtInterpreterToCompiledCodeBridge(Thread* self,
ArtMethod* caller,
- const DexFile::CodeItem* code_item,
ShadowFrame* shadow_frame,
+ uint16_t arg_offset,
JValue* result)
REQUIRES_SHARED(Locks::mutator_lock_) {
ArtMethod* method = shadow_frame->GetMethod();
@@ -482,9 +482,15 @@
method = shadow_frame->GetMethod();
}
}
- uint16_t arg_offset = (code_item == nullptr)
- ? 0
- : code_item->registers_size_ - code_item->ins_size_;
+ // Basic checks for the arg_offset. If there's no code item, the arg_offset must be 0. Otherwise,
+ // check that the arg_offset isn't greater than the number of registers. A stronger check is
+ // difficult since the frame may contain space for all the registers in the method, or only enough
+ // space for the arguments.
+ if (method->GetCodeItem() == nullptr) {
+ DCHECK_EQ(0u, arg_offset) << method->PrettyMethod();
+ } else {
+ DCHECK_LE(arg_offset, shadow_frame->NumberOfVRegs());
+ }
jit::Jit* jit = Runtime::Current()->GetJit();
if (jit != nullptr && caller != nullptr) {
jit->NotifyInterpreterToCompiledCodeTransition(self, caller);
@@ -918,12 +924,20 @@
// Compute method information.
const DexFile::CodeItem* code_item = called_method->GetCodeItem();
-
// Number of registers for the callee's call frame.
uint16_t num_regs;
if (LIKELY(code_item != nullptr)) {
- num_regs = code_item->registers_size_;
- DCHECK_EQ(string_init ? number_of_inputs - 1 : number_of_inputs, code_item->ins_size_);
+ // When transitioning to compiled code, space only needs to be reserved for the input registers.
+ // The rest of the frame gets discarded. This also prevents accessing the called method's code
+ // item, saving memory by keeping code items of compiled code untouched.
+ if (Runtime::Current()->IsStarted() &&
+ !ClassLinker::ShouldUseInterpreterEntrypoint(
+ called_method, called_method->GetEntryPointFromQuickCompiledCode())) {
+ num_regs = number_of_inputs;
+ } else {
+ num_regs = code_item->registers_size_;
+ DCHECK_EQ(string_init ? number_of_inputs - 1 : number_of_inputs, code_item->ins_size_);
+ }
} else {
DCHECK(called_method->IsNative() || called_method->IsProxyMethod());
num_regs = number_of_inputs;
diff --git a/runtime/interpreter/interpreter_common.h b/runtime/interpreter/interpreter_common.h
index 2589ad0..67e072d 100644
--- a/runtime/interpreter/interpreter_common.h
+++ b/runtime/interpreter/interpreter_common.h
@@ -527,10 +527,11 @@
}
}
+// The arg_offset is the offset to the first input register in the frame.
void ArtInterpreterToCompiledCodeBridge(Thread* self,
ArtMethod* caller,
- const DexFile::CodeItem* code_item,
ShadowFrame* shadow_frame,
+ uint16_t arg_offset,
JValue* result);
// Set string value created from StringFactory.newStringFromXXX() into all aliases of
