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// 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.
#ifndef VM_FLOW_GRAPH_BUILDER_H_
#define VM_FLOW_GRAPH_BUILDER_H_
#include "vm/allocation.h"
#include "vm/ast.h"
#include "vm/growable_array.h"
#include "vm/intermediate_language.h"
namespace dart {
class FlowGraph;
class Instruction;
class ParsedFunction;
// An class to collect the exits from an inlined function during graph
// construction so they can be plugged into the caller's flow graph.
class InlineExitCollector: public ZoneAllocated {
public:
InlineExitCollector(FlowGraph* caller_graph, Definition* call)
: caller_graph_(caller_graph), call_(call), exits_(4) { }
void AddExit(ReturnInstr* exit);
// Before replacing a call with a graph, the outer environment needs to be
// attached to each instruction in the callee graph and the caller graph
// needs to have its block and instruction ID state updated.
void PrepareGraphs(FlowGraph* callee_graph);
// Inline a graph at a call site.
//
// Assumes the callee is in SSA with a correct dominator tree and use
// lists.
//
// After inlining the caller graph will have correctly adjusted the use
// lists. The block orders will need to be recomputed.
void ReplaceCall(TargetEntryInstr* callee_entry);
private:
struct Data {
BlockEntryInstr* exit_block;
ReturnInstr* exit_return;
};
BlockEntryInstr* ExitBlockAt(intptr_t i) const {
ASSERT(exits_[i].exit_block != NULL);
return exits_[i].exit_block;
}
Instruction* LastInstructionAt(intptr_t i) const {
return ReturnAt(i)->previous();
}
Value* ValueAt(intptr_t i) const {
return ReturnAt(i)->value();
}
ReturnInstr* ReturnAt(intptr_t i) const {
return exits_[i].exit_return;
}
static int LowestBlockIdFirst(const Data* a, const Data* b);
void SortExits();
Definition* JoinReturns(BlockEntryInstr** exit_block,
Instruction** last_instruction);
FlowGraph* caller_graph_;
Definition* call_;
GrowableArray<Data> exits_;
};
// Build a flow graph from a parsed function's AST.
class FlowGraphBuilder: public ValueObject {
public:
// The inlining context is NULL if not inlining.
FlowGraphBuilder(const ParsedFunction& parsed_function,
InlineExitCollector* exit_collector);
FlowGraph* BuildGraph();
const ParsedFunction& parsed_function() const { return parsed_function_; }
void Bailout(const char* reason);
intptr_t AllocateBlockId() { return ++last_used_block_id_; }
void SetInitialBlockId(intptr_t id) { last_used_block_id_ = id; }
void set_context_level(intptr_t value) { context_level_ = value; }
intptr_t context_level() const { return context_level_; }
// Each try in this function gets its own try index.
intptr_t AllocateTryIndex() { return ++last_used_try_index_; }
// Manage the currently active try index.
void set_try_index(intptr_t value) { try_index_ = value; }
intptr_t try_index() const { return try_index_; }
void AddCatchEntry(CatchBlockEntryInstr* entry);
intptr_t num_copied_params() const {
return num_copied_params_;
}
intptr_t num_non_copied_params() const {
return num_non_copied_params_;
}
intptr_t num_stack_locals() const {
return num_stack_locals_;
}
bool IsInlining() const { return (exit_collector_ != NULL); }
InlineExitCollector* exit_collector() const { return exit_collector_; }
private:
intptr_t parameter_count() const {
return num_copied_params_ + num_non_copied_params_;
}
intptr_t variable_count() const {
return parameter_count() + num_stack_locals_;
}
const ParsedFunction& parsed_function_;
const intptr_t num_copied_params_;
const intptr_t num_non_copied_params_;
const intptr_t num_stack_locals_; // Does not include any parameters.
InlineExitCollector* const exit_collector_;
intptr_t last_used_block_id_;
intptr_t context_level_;
intptr_t last_used_try_index_;
intptr_t try_index_;
GraphEntryInstr* graph_entry_;
DISALLOW_IMPLICIT_CONSTRUCTORS(FlowGraphBuilder);
};
class TestGraphVisitor;
// Translate an AstNode to a control-flow graph fragment for its effects
// (e.g., a statement or an expression in an effect context). Implements a
// function from an AstNode and next temporary index to a graph fragment
// with a single entry and at most one exit. The fragment is represented by
// an (entry, exit) pair of Instruction pointers:
//
// - (NULL, NULL): an empty and open graph fragment
// - (i0, NULL): a closed graph fragment which has only non-local exits
// - (i0, i1): an open graph fragment
class EffectGraphVisitor : public AstNodeVisitor {
public:
EffectGraphVisitor(FlowGraphBuilder* owner,
intptr_t temp_index)
: owner_(owner),
temp_index_(temp_index),
entry_(NULL),
exit_(NULL) { }
#define DEFINE_VISIT(type, name) virtual void Visit##type(type* node);
NODE_LIST(DEFINE_VISIT)
#undef DEFINE_VISIT
FlowGraphBuilder* owner() const { return owner_; }
intptr_t temp_index() const { return temp_index_; }
Instruction* entry() const { return entry_; }
Instruction* exit() const { return exit_; }
bool is_empty() const { return entry_ == NULL; }
bool is_open() const { return is_empty() || exit_ != NULL; }
void Bailout(const char* reason);
void InlineBailout(const char* reason);
// Append a graph fragment to this graph. Assumes this graph is open.
void Append(const EffectGraphVisitor& other_fragment);
// Append a definition that can have uses. Assumes this graph is open.
Value* Bind(Definition* definition);
// Append a computation with no uses. Assumes this graph is open.
void Do(Definition* definition);
// Append a single (non-Definition, non-Entry) instruction. Assumes this
// graph is open.
void AddInstruction(Instruction* instruction);
// Append a Goto (unconditional control flow) instruction and close
// the graph fragment. Assumes this graph fragment is open.
void Goto(JoinEntryInstr* join);
// Append a 'diamond' branch and join to this graph, depending on which
// parts are reachable. Assumes this graph is open.
void Join(const TestGraphVisitor& test_fragment,
const EffectGraphVisitor& true_fragment,
const EffectGraphVisitor& false_fragment);
// Append a 'while loop' test and back edge to this graph, depending on
// which parts are reachable. Afterward, the graph exit is the false
// successor of the loop condition.
void TieLoop(const TestGraphVisitor& test_fragment,
const EffectGraphVisitor& body_fragment);
// Wraps a value in a push-argument instruction and adds the result to the
// graph.
PushArgumentInstr* PushArgument(Value* value);
// This implementation shares state among visitors by using the builder.
// The implementation is incorrect if a visitor that hits a return is not
// actually added to the graph.
void AddReturnExit(intptr_t token_pos, Value* value);
protected:
Definition* BuildStoreTemp(const LocalVariable& local, Value* value);
Definition* BuildStoreExprTemp(Value* value);
Definition* BuildLoadExprTemp();
Definition* BuildStoreLocal(const LocalVariable& local,
Value* value,
bool result_is_needed);
Definition* BuildLoadLocal(const LocalVariable& local);
void HandleStoreLocal(StoreLocalNode* node, bool result_is_needed);
// Helpers for translating parts of the AST.
void TranslateArgumentList(const ArgumentListNode& node,
ZoneGrowableArray<Value*>* values);
void BuildPushArguments(const ArgumentListNode& node,
ZoneGrowableArray<PushArgumentInstr*>* values);
// Creates an instantiated type argument vector used in preparation of an
// allocation call.
// May be called only if allocating an object of a parameterized class.
Value* BuildInstantiatedTypeArguments(
intptr_t token_pos,
const AbstractTypeArguments& type_arguments);
// Creates a possibly uninstantiated type argument vector and the type
// argument vector of the instantiator used in
// preparation of a constructor call.
// May be called only if allocating an object of a parameterized class.
void BuildConstructorTypeArguments(
ConstructorCallNode* node,
Value** type_arguments,
Value** instantiator,
ZoneGrowableArray<PushArgumentInstr*>* call_arguments);
void BuildTypecheckPushArguments(
intptr_t token_pos,
PushArgumentInstr** push_instantiator,
PushArgumentInstr** push_instantiator_type_arguments);
void BuildTypecheckArguments(intptr_t token_pos,
Value** instantiator,
Value** instantiator_type_arguments);
Value* BuildInstantiator();
Value* BuildInstantiatorTypeArguments(intptr_t token_pos,
Value* instantiator);
// Perform a type check on the given value.
AssertAssignableInstr* BuildAssertAssignable(intptr_t token_pos,
Value* value,
const AbstractType& dst_type,
const String& dst_name);
// Perform a type check on the given value and return it.
Value* BuildAssignableValue(intptr_t token_pos,
Value* value,
const AbstractType& dst_type,
const String& dst_name);
static const bool kResultNeeded = true;
static const bool kResultNotNeeded = false;
Definition* BuildStoreIndexedValues(StoreIndexedNode* node,
bool result_is_needed);
void BuildInstanceSetterArguments(
InstanceSetterNode* node,
ZoneGrowableArray<PushArgumentInstr*>* arguments,
bool result_is_needed);
virtual void BuildTypeTest(ComparisonNode* node);
virtual void BuildTypeCast(ComparisonNode* node);
bool MustSaveRestoreContext(SequenceNode* node) const;
// Moves parent context into the context register.
void UnchainContext();
void CloseFragment() { exit_ = NULL; }
intptr_t AllocateTempIndex() { return temp_index_++; }
void DeallocateTempIndex(intptr_t n) {
ASSERT(temp_index_ >= n);
temp_index_ -= n;
}
Value* BuildObjectAllocation(ConstructorCallNode* node);
void BuildConstructorCall(ConstructorCallNode* node,
PushArgumentInstr* alloc_value);
void BuildStoreContext(const LocalVariable& variable);
void BuildLoadContext(const LocalVariable& variable);
void BuildThrowNode(ThrowNode* node);
StaticCallInstr* BuildStaticNoSuchMethodCall(
const Class& target_class,
AstNode* receiver,
const String& method_name,
ArgumentListNode* method_arguments);
StaticCallInstr* BuildThrowNoSuchMethodError(intptr_t token_pos,
const Class& function_class,
const String& function_name,
int invocation_type);
void BuildStaticSetter(StaticSetterNode* node, bool result_is_needed);
Definition* BuildStoreStaticField(StoreStaticFieldNode* node,
bool result_is_needed);
ClosureCallInstr* BuildClosureCall(ClosureCallNode* node);
Value* BuildNullValue();
private:
// Specify a definition of the final result. Adds the definition to
// the graph, but normally overridden in subclasses.
virtual void ReturnDefinition(Definition* definition) {
Do(definition);
}
protected:
// Returns true if the run-time type check can be eliminated.
bool CanSkipTypeCheck(intptr_t token_pos,
Value* value,
const AbstractType& dst_type,
const String& dst_name);
private:
// Shared global state.
FlowGraphBuilder* owner_;
// Input parameters.
intptr_t temp_index_;
// Output parameters.
Instruction* entry_;
Instruction* exit_;
};
// Translate an AstNode to a control-flow graph fragment for both its effects
// and value (e.g., for an expression in a value context). Implements a
// function from an AstNode and next temporary index to a graph fragment (as
// in the EffectGraphVisitor), a next temporary index, and an intermediate
// language Value.
class ValueGraphVisitor : public EffectGraphVisitor {
public:
ValueGraphVisitor(FlowGraphBuilder* owner,
intptr_t temp_index)
: EffectGraphVisitor(owner, temp_index), value_(NULL) { }
// Visit functions overridden by this class.
virtual void VisitLiteralNode(LiteralNode* node);
virtual void VisitAssignableNode(AssignableNode* node);
virtual void VisitConstructorCallNode(ConstructorCallNode* node);
virtual void VisitBinaryOpNode(BinaryOpNode* node);
virtual void VisitConditionalExprNode(ConditionalExprNode* node);
virtual void VisitLoadLocalNode(LoadLocalNode* node);
virtual void VisitStoreLocalNode(StoreLocalNode* node);
virtual void VisitStoreIndexedNode(StoreIndexedNode* node);
virtual void VisitStoreInstanceFieldNode(StoreInstanceFieldNode* node);
virtual void VisitInstanceSetterNode(InstanceSetterNode* node);
virtual void VisitThrowNode(ThrowNode* node);
virtual void VisitClosureCallNode(ClosureCallNode* node);
virtual void VisitStaticSetterNode(StaticSetterNode* node);
virtual void VisitStoreStaticFieldNode(StoreStaticFieldNode* node);
virtual void VisitTypeNode(TypeNode* node);
Value* value() const { return value_; }
protected:
// Output parameters.
Value* value_;
private:
// Helper to set the output state to return a Value.
virtual void ReturnValue(Value* value) { value_ = value; }
// Specify a definition of the final result. Adds the definition to
// the graph and returns a use of it (i.e., set the visitor's output
// parameters).
virtual void ReturnDefinition(Definition* definition) {
ReturnValue(Bind(definition));
}
virtual void BuildTypeTest(ComparisonNode* node);
virtual void BuildTypeCast(ComparisonNode* node);
};
// Translate an AstNode to a control-flow graph fragment for both its
// effects and true/false control flow (e.g., for an expression in a test
// context). The resulting graph is always closed (even if it is empty)
// Successor control flow is explicitly set by a pair of pointers to
// TargetEntryInstr*.
//
// To distinguish between the graphs with only nonlocal exits and graphs
// with both true and false exits, there are a pair of TargetEntryInstr**:
//
// - Both NULL: only non-local exits, truly closed
// - Neither NULL: true and false successors at the given addresses
//
// We expect that AstNode in test contexts either have only nonlocal exits
// or else control flow has both true and false successors.
//
// The cis and token_pos are used in checked mode to verify that the
// condition of the test is of type bool.
class TestGraphVisitor : public ValueGraphVisitor {
public:
TestGraphVisitor(FlowGraphBuilder* owner,
intptr_t temp_index,
intptr_t condition_token_pos)
: ValueGraphVisitor(owner, temp_index),
true_successor_addresses_(1),
false_successor_addresses_(1),
condition_token_pos_(condition_token_pos) { }
void IfFalseGoto(JoinEntryInstr* join) const;
void IfTrueGoto(JoinEntryInstr* join) const;
BlockEntryInstr* CreateTrueSuccessor() const;
BlockEntryInstr* CreateFalseSuccessor() const;
virtual void VisitBinaryOpNode(BinaryOpNode* node);
intptr_t condition_token_pos() const { return condition_token_pos_; }
private:
// Construct and concatenate a Branch instruction to this graph fragment.
// Closes the fragment and sets the output parameters.
virtual void ReturnValue(Value* value);
// Either merges the definition into a BranchInstr (Comparison, BooleanNegate)
// or adds the definition to the graph and returns a use of its value.
virtual void ReturnDefinition(Definition* definition);
void MergeBranchWithComparison(ComparisonInstr* comp);
void MergeBranchWithNegate(BooleanNegateInstr* comp);
BlockEntryInstr* CreateSuccessorFor(
const GrowableArray<TargetEntryInstr**>& branches) const;
void ConnectBranchesTo(
const GrowableArray<TargetEntryInstr**>& branches,
JoinEntryInstr* join) const;
// Output parameters.
GrowableArray<TargetEntryInstr**> true_successor_addresses_;
GrowableArray<TargetEntryInstr**> false_successor_addresses_;
intptr_t condition_token_pos_;
};
} // namespace dart
#endif // VM_FLOW_GRAPH_BUILDER_H_