Add enough compiler support to compile empty functions on x64.

runtime/vm/flow_graph_compiler_x64.cc

+// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+#include "vm/globals.h"  // Needed here to get TARGET_ARCH_X64.
+#if defined(TARGET_ARCH_X64)
+
+#include "vm/flow_graph_compiler.h"
+
+#include "vm/ast_printer.h"
+#include "vm/code_generator.h"
+#include "vm/disassembler.h"
+#include "vm/longjump.h"
+#include "vm/parser.h"
+#include "vm/stub_code.h"
+
+namespace dart {
+
+DECLARE_FLAG(bool, print_ast);
+DECLARE_FLAG(bool, print_scopes);
+DECLARE_FLAG(bool, trace_functions);
+DECLARE_FLAG(bool, disassemble);
+
+void FlowGraphCompiler::Bailout(const char* reason) {
+  const char* kFormat = "FlowGraphCompiler Bailout: %s.";
+  intptr_t len = OS::SNPrint(NULL, 0, kFormat, reason) + 1;
+  char* chars = reinterpret_cast<char*>(
+      Isolate::Current()->current_zone()->Allocate(len));
+  OS::SNPrint(chars, len, kFormat, reason);
+  const Error& error = Error::Handle(
+      LanguageError::New(String::Handle(String::New(chars))));
+  Isolate::Current()->long_jump_base()->Jump(1, error);
+}
+
+
+#define __ assembler_->
+
+void FlowGraphCompiler::CompileValue(Value* value) {
+  if (value->IsConstant()) {
+    ConstantValue* constant = value->AsConstant();
+    if (constant->instance().IsSmi()) {
+      int64_t imm = reinterpret_cast<int64_t>(constant->instance().raw());
+      __ movq(RAX, Immediate(imm));
+    } else {
+      __ LoadObject(RAX, value->AsConstant()->instance());
+    }
+  } else {
+    ASSERT(value->IsTemp());
+    Bailout("return of non-ConstantValue value");
+  }
+}
+
+
+void FlowGraphCompiler::VisitJoinEntry(JoinEntryInstr* instr) {
+  Bailout("JoinEntryInstr");
+}
+
+
+void FlowGraphCompiler::VisitTargetEntry(TargetEntryInstr* instr) {
+  // Since we don't handle branching control flow yet, there is nothing to do.
+}
+
+
+void FlowGraphCompiler::VisitDo(DoInstr* instr) {
+  Bailout("DoInstr");
+}
+
+
+void FlowGraphCompiler::VisitBind(BindInstr* instr) {
+  Bailout("DoInstr");
+}
+
+
+void FlowGraphCompiler::VisitReturn(ReturnInstr* instr) {
+  CompileValue(instr->value());
+
+#ifdef DEBUG
+  // Check that the entry stack size matches the exit stack size.
+  const intptr_t locals_space_size = 0;
+  __ movq(R10, RBP);
+  __ subq(R10, RSP);
+  __ cmpq(R10, Immediate(locals_space_size));
+  Label stack_ok;
+  __ j(EQUAL, &stack_ok, Assembler::kNearJump);
+  __ Stop("Exit stack size does not match the entry stack size.");
+  __ Bind(&stack_ok);
+#endif  // DEBUG.
+
+  if (FLAG_trace_functions) {
+    __ pushq(RAX);  // Preserve result.
+    const Function& function =
+        Function::ZoneHandle(parsed_function_.function().raw());
+    __ LoadObject(RBX, function);
+    __ pushq(RBX);
+    GenerateCallRuntime(AstNode::kNoId,
+                        0,
+                        kTraceFunctionExitRuntimeEntry);
+    __ popq(RAX);  // Remove argument.
+    __ popq(RAX);  // Restore result.
+  }
+  __ LeaveFrame();
+  __ ret();
+}
+
+
+void FlowGraphCompiler::VisitBranch(BranchInstr* instr) {
+  Bailout("VisitBranch");
+}
+
+
+void FlowGraphCompiler::CompileGraph() {
+  const Function& function = parsed_function_.function();
+  if ((function.num_fixed_parameters() != 0) ||
+      (function.num_optional_parameters() != 0)) {
+    Bailout("function has parameters");
+  }
+  LocalScope* scope = parsed_function_.node_sequence()->scope();
+  if (scope->child() != NULL) {
+    Bailout("function has local scopes");
+  }
+  LocalScope* context_owner = NULL;
+  const int first_parameter_index = 1;
+  const int parameter_count = 0;
+  const int first_local_index = -1;
+  int first_free_frame_index =
+      scope->AllocateVariables(first_parameter_index,
+                               parameter_count,
+                               first_local_index,
+                               scope,
+                               &context_owner);
+  const int local_count = first_local_index - first_free_frame_index;
+  if (local_count != 0) Bailout("function has locals");
+
+  if (blocks_->length() != 1) Bailout("more than 1 basic block");
+
+  // Specialized version of entry code from CodeGenerator::GenerateEntryCode.
+  __ EnterFrame(0);
+#ifdef DEBUG
+  const bool check_arguments = true;
+#else
+  const bool check_arguments = function.IsClosureFunction();
+#endif
+  if (check_arguments) {
+    // Check that num_fixed <= argc <= num_params.
+    Label argc_in_range;
+    // Total number of args is the first Smi in args descriptor array (R10).
+    __ movq(RAX, FieldAddress(R10, Array::data_offset()));
+    __ cmpq(RAX, Immediate(Smi::RawValue(0)));
+    __ j(EQUAL, &argc_in_range, Assembler::kNearJump);
+    if (function.IsClosureFunction()) {
+      GenerateCallRuntime(AstNode::kNoId,
+                          function.token_index(),
+                          kClosureArgumentMismatchRuntimeEntry);
+    } else {
+      __ Stop("Wrong number of arguments");
+    }
+    __ Bind(&argc_in_range);
+  }
+  // Generate stack overflow check.
+  __ movq(TMP, Immediate(Isolate::Current()->stack_limit_address()));
+  __ cmpq(RSP, Address(TMP, 0));
+  Label no_stack_overflow;
+  __ j(ABOVE, &no_stack_overflow);
+  GenerateCallRuntime(AstNode::kNoId,
+                      function.token_index(),
+                      kStackOverflowRuntimeEntry);
+  __ Bind(&no_stack_overflow);
+
+  if (FLAG_print_scopes) {
+    // Print the function scope (again) after generating the prologue in order
+    // to see annotations such as allocation indices of locals.
+    if (FLAG_print_ast) {
+      // Second printing.
+      OS::Print("Annotated ");
+    }
+    AstPrinter::PrintFunctionScope(parsed_function_);
+  }
+
+  VisitBlocks(*blocks_);
+
+  __ int3();
+  // Emit function patching code. This will be swapped with the first 13 bytes
+  // at entry point.
+  pc_descriptors_list_->AddDescriptor(PcDescriptors::kPatchCode,
+                                      assembler_->CodeSize(),
+                                      AstNode::kNoId,
+                                      0,
+                                      -1);
+  __ jmp(&StubCode::FixCallersTargetLabel());
+
+  if (FLAG_disassemble) {
+    const char* function_fullname = function.ToFullyQualifiedCString();
+    OS::Print(";;; Function %s\n", function_fullname);
+    const Code& code = Code::Handle(Code::FinalizeCode("GRAPH", assembler_));
+    const Instructions& instructions =
+        Instructions::Handle(code.instructions());
+    uword start = instructions.EntryPoint();
+    Disassembler::Disassemble(start, start + assembler_->CodeSize());
+    OS::Print("\n");
+  }
+}
+
+
+// Infrastructure copied from class CodeGenerator.
+void FlowGraphCompiler::GenerateCallRuntime(intptr_t node_id,
+                                            intptr_t token_index,
+                                            const RuntimeEntry& entry) {
+  __ CallRuntimeFromDart(entry);
+  AddCurrentDescriptor(PcDescriptors::kOther, node_id, token_index);
+}
+
+
+// Uses current pc position and try-index.
+void FlowGraphCompiler::AddCurrentDescriptor(PcDescriptors::Kind kind,
+                                             intptr_t node_id,
+                                             intptr_t token_index) {
+  pc_descriptors_list_->AddDescriptor(kind,
+                                      assembler_->CodeSize(),
+                                      node_id,
+                                      token_index,
+                                      CatchClauseNode::kInvalidTryIndex);
+}
+
+
+}  // namespace dart
+
+#endif  // defined TARGET_ARCH_X64