Introduce a lazy-compile stub for functions.

runtime/vm/stub_code_mips.cc

Index: runtime/vm/stub_code_mips.cc
===================================================================
--- runtime/vm/stub_code_mips.cc	(revision 34118)
+++ runtime/vm/stub_code_mips.cc	(working copy)
@@ -908,42 +908,21 @@
   __ beq(T0, T7, &not_closure);
 
   // T0 is just the signature function. Load the actual closure function.
-  __ lw(T2, FieldAddress(T1, Closure::function_offset()));
+  __ lw(T0, FieldAddress(T1, Closure::function_offset()));
 
   // Load closure context in CTX; note that CTX has already been preserved.
   __ lw(CTX, FieldAddress(T1, Closure::context_offset()));
 
+  // Load closure function code in T2.
   Label function_compiled;
-  // Load closure function code in T0.
-  __ lw(T0, FieldAddress(T2, Function::code_offset()));
-  __ bne(T0, T7, &function_compiled);
+  __ lw(T2, FieldAddress(T0, Function::code_offset()));
+  __ beq(T2, T7, &function_compiled);
+  __ Branch(&StubCode::LazyCompileClosureLabel());
 
-  // Create a stub frame as we are pushing some objects on the stack before
-  // calling into the runtime.
-  __ EnterStubFrame();
-
-  // Preserve arguments descriptor array and read-only function object argument.
-  __ addiu(SP, SP, Immediate(-2 * kWordSize));
-  __ sw(S4, Address(SP, 1 * kWordSize));
-  __ sw(T2, Address(SP, 0 * kWordSize));
-  __ CallRuntime(kCompileFunctionRuntimeEntry, 1);
-  __ TraceSimMsg("GenerateCallClosureFunctionStub return");
-  // Restore arguments descriptor array and read-only function object argument.
-  __ lw(T2, Address(SP, 0 * kWordSize));
-  __ lw(S4, Address(SP, 1 * kWordSize));
-  __ addiu(SP, SP, Immediate(2 * kWordSize));
-  // Restore T0.
-  __ lw(T0, FieldAddress(T2, Function::code_offset()));
-
-  // Remove the stub frame as we are about to jump to the closure function.
-  __ LeaveStubFrame();
-
   __ Bind(&function_compiled);
-  // T0: Code.
-  // S4: Arguments descriptor array.
-  __ lw(T0, FieldAddress(T0, Code::instructions_offset()));
-  __ AddImmediate(T0, Instructions::HeaderSize() - kHeapObjectTag);
-  __ jr(T0);
+  __ lw(T2, FieldAddress(T2, Code::instructions_offset()));
+  __ AddImmediate(T2, Instructions::HeaderSize() - kHeapObjectTag);
+  __ jr(T2);
 
   __ Bind(&not_closure);
   // Call runtime to attempt to resolve and invoke a call method on a
@@ -1738,24 +1717,14 @@
   __ sw(T1, Address(T0, count_offset));
 
   __ Bind(&call_target_function);
-  // T3: Target function.
+  // T0 <- T3: Target function.
+  __ mov(T0, T3);
   Label is_compiled;
   __ lw(T4, FieldAddress(T3, Function::code_offset()));
   if (FLAG_collect_code) {
     __ BranchNotEqual(T4, reinterpret_cast<int32_t>(Object::null()),
                       &is_compiled);
-    __ EnterStubFrame();
-    __ addiu(SP, SP, Immediate(-3 * kWordSize));
-    __ sw(S5, Address(SP, 2 * kWordSize));  // Preserve IC data.
-    __ sw(S4, Address(SP, 1 * kWordSize));  // Preserve arg desc.
-    __ sw(T3, Address(SP, 0 * kWordSize));  // Function argument.
-    __ CallRuntime(kCompileFunctionRuntimeEntry, 1);
-    __ lw(T3, Address(SP, 0 * kWordSize));  // Restore Function.
-    __ lw(S4, Address(SP, 1 * kWordSize));  // Restore arg desc.
-    __ lw(S5, Address(SP, 2 * kWordSize));  // Restore IC data.
-    __ addiu(SP, SP, Immediate(3 * kWordSize));
-    __ LeaveStubFrame();
-    __ lw(T4, FieldAddress(T3, Function::code_offset()));
+    __ Branch(&StubCode::LazyCompileLabel());
     __ Bind(&is_compiled);
   }
   __ lw(T3, FieldAddress(T4, Code::instructions_offset()));
@@ -1900,36 +1869,22 @@
 
   __ Bind(&increment_done);
 
+  // Load arguments descriptor into S4.
+  __ lw(S4,  FieldAddress(S5, ICData::arguments_descriptor_offset()));
+
   Label target_is_compiled;
   // Get function and call it, if possible.
-  __ lw(T3, Address(T0, target_offset));
-  __ lw(T4, FieldAddress(T3, Function::code_offset()));
+  __ lw(T0, Address(T0, target_offset));
+  __ lw(T4, FieldAddress(T0, Function::code_offset()));
   __ LoadImmediate(CMPRES1, reinterpret_cast<intptr_t>(Object::null()));
   __ bne(T4, CMPRES1, &target_is_compiled);
+  __ Branch(&StubCode::LazyCompileLabel());
 
-  __ EnterStubFrame();
-  // Preserve target function and IC data object.
-  // Two preserved registers, one argument (function) => 3 slots.
-  __ addiu(SP, SP, Immediate(-3 * kWordSize));
-  __ sw(S5, Address(SP, 2 * kWordSize));  // Preserve IC data.
-  __ sw(T3, Address(SP, 1 * kWordSize));  // Preserve function.
-  __ sw(T3, Address(SP, 0 * kWordSize));  // Function argument.
-  __ CallRuntime(kCompileFunctionRuntimeEntry, 1);
-  __ lw(T3, Address(SP, 1 * kWordSize));  // Restore function.
-  __ lw(S5, Address(SP, 2 * kWordSize));  // Restore IC data.
-  __ addiu(SP, SP, Immediate(3 * kWordSize));
-  // T3: target function.
-  __ lw(T4, FieldAddress(T3, Function::code_offset()));
-  __ LeaveStubFrame();
-
   __ Bind(&target_is_compiled);
   // T4: target code.
   __ lw(T3, FieldAddress(T4, Code::instructions_offset()));
   __ AddImmediate(T3, Instructions::HeaderSize() - kHeapObjectTag);
   __ jr(T3);
-  // Load arguments descriptor into S4.
-  __ delay_slot()->
-      lw(S4,  FieldAddress(S5, ICData::arguments_descriptor_offset()));
 }
 
 
@@ -1940,11 +1895,11 @@
 }
 
 
-// Stub for calling the CompileFunction runtime call.
+// Stub for compiling a function and jumping to the compiled code.
 // S5: IC-Data.
 // S4: Arguments descriptor.
 // T0: Function.
-void StubCode::GenerateCompileFunctionRuntimeCallStub(Assembler* assembler) {
+void StubCode::GenerateLazyCompileStub(Assembler* assembler) {
   __ EnterStubFrame();
   __ addiu(SP, SP, Immediate(-3 * kWordSize));
   __ sw(S5, Address(SP, 2 * kWordSize));  // Preserve IC data object.
@@ -1954,6 +1909,44 @@
   __ lw(T0, Address(SP, 0 * kWordSize));  // Restore function.
   __ lw(S4, Address(SP, 1 * kWordSize));  // Restore args descriptor array.
   __ lw(S5, Address(SP, 2 * kWordSize));  // Restore IC data array.
+  __ LeaveStubFrame();
+
+  __ lw(T2, FieldAddress(T0, Function::code_offset()));
+  __ lw(T2, FieldAddress(T2, Code::instructions_offset()));
+  __ AddImmediate(T2, Instructions::HeaderSize() - kHeapObjectTag);
+  __ jr(T2);
+}
+
+
+// Stub for compiling a closure and jumping to the compiled code.
+// S5: IC-Data.
+// S4: Arguments descriptor.
+// T0: Function.
+void StubCode::GenerateLazyCompileClosureStub(Assembler* assembler) {
+  __ EnterStubFrame();
+  __ addiu(SP, SP, Immediate(-3 * kWordSize));
+  __ sw(S4, Address(SP, 1 * kWordSize));  // Preserve args descriptor array.
+  __ sw(T0, Address(SP, 0 * kWordSize));  // Pass function.
+  __ CallRuntime(kCompileFunctionRuntimeEntry, 1);
+  __ lw(T0, Address(SP, 0 * kWordSize));  // Restore function.
+  __ lw(S4, Address(SP, 1 * kWordSize));  // Restore args descriptor array.
+  __ LeaveStubFrame();
+
+  __ lw(T2, FieldAddress(T0, Function::code_offset()));
+  __ lw(T2, FieldAddress(T2, Code::instructions_offset()));
+  __ AddImmediate(T2, Instructions::HeaderSize() - kHeapObjectTag);
+  __ jr(T2);
+}
+
+
+// Stub for calling the CompileFunction runtime call.
+// T0: Function.
+void StubCode::GenerateCompileFunctionRuntimeCallStub(Assembler* assembler) {
+  __ EnterStubFrame();
+  __ addiu(SP, SP, Immediate(-2 * kWordSize));
+  __ sw(T0, Address(SP, 0 * kWordSize));  // Pass function.
+  __ CallRuntime(kCompileFunctionRuntimeEntry, 1);
+  __ lw(T0, Address(SP, 0 * kWordSize));  // Restore function.
   __ LeaveStubFrameAndReturn();
 }