Reviewers: jarin,
Description:
[turbofan] Add some documenting comments to RawMachineAssembler.
[email protected]
Please review this at https://codereview.chromium.org/1248263003/
Base URL:
https://chromium.googlesource.com/v8/v8.git@local_cleanup-graph-builder-base
Affected files (+35, -20 lines):
M src/compiler/raw-machine-assembler.h
M src/compiler/raw-machine-assembler.cc
Index: src/compiler/raw-machine-assembler.cc
diff --git a/src/compiler/raw-machine-assembler.cc
b/src/compiler/raw-machine-assembler.cc
index
c089241a2f7210ff480e25c1ec70b0698c200bcc..6e80bb0c83018ede4006a339c8b8f544dd392c06
100644
--- a/src/compiler/raw-machine-assembler.cc
+++ b/src/compiler/raw-machine-assembler.cc
@@ -39,7 +39,7 @@ Schedule* RawMachineAssembler::Export() {
// Compute the correct codegen order.
DCHECK(schedule_->rpo_order()->empty());
Scheduler::ComputeSpecialRPO(zone(), schedule_);
- // Invalidate MachineAssembler.
+ // Invalidate RawMachineAssembler.
Schedule* schedule = schedule_;
schedule_ = NULL;
return schedule;
@@ -243,7 +243,7 @@ BasicBlock* RawMachineAssembler::CurrentBlock() {
Node* RawMachineAssembler::MakeNode(const Operator* op, int input_count,
Node** inputs) {
- DCHECK(ScheduleValid());
+ DCHECK_NOT_NULL(schedule_);
DCHECK(current_block_ != NULL);
Node* node = graph()->NewNode(op, input_count, inputs);
BasicBlock* block = op->opcode() == IrOpcode::kParameter ?
schedule()->start()
Index: src/compiler/raw-machine-assembler.h
diff --git a/src/compiler/raw-machine-assembler.h
b/src/compiler/raw-machine-assembler.h
index
79f5ed593bd350742c27906c98622c8eda782531..17dd5fd75f7fa31c44b3910f7b6f626289c80c03
100644
--- a/src/compiler/raw-machine-assembler.h
+++ b/src/compiler/raw-machine-assembler.h
@@ -20,7 +20,13 @@ namespace compiler {
class BasicBlock;
class Schedule;
-
+// The RawMachineAssembler produces a low-level IR graph. All nodes are
wired
+// into a graph and also placed into a schedule immediately, hence
subsequent
+// code generation can happen without the need for scheduling.
+//
+// In order to create a schedule on-the-fly, the assembler keeps track of
basic
+// blocks by having one current basic block being populated and by
referencing
+// other basic blocks through the use of labels.
class RawMachineAssembler {
public:
class Label {
@@ -51,6 +57,7 @@ class RawMachineAssembler {
Isolate* isolate() const { return isolate_; }
Graph* graph() const { return graph_; }
+ Schedule* schedule() { return schedule_; }
Zone* zone() const { return graph()->zone(); }
MachineOperatorBuilder* machine() { return &machine_; }
CommonOperatorBuilder* common() { return &common_; }
@@ -60,6 +67,15 @@ class RawMachineAssembler {
return call_descriptor_->GetMachineSignature();
}
+ // Finalizes the schedule and exports it to be used for code generation.
Note
+ // that this RawMachineAssembler becomes invalid after export.
+ Schedule* Export();
+
+ //
===========================================================================
+ // The following utility methods create new nodes with specific
operators and
+ // place them into the current basic block. They don't perform control
flow,
+ // hence will not switch the current basic block.
+
Node* UndefinedConstant() {
Unique<HeapObject> unique = Unique<HeapObject>::CreateImmovable(
isolate()->factory()->undefined_value());
@@ -117,6 +133,7 @@ class RawMachineAssembler {
NewNode(machine()->Store(StoreRepresentation(rep, kNoWriteBarrier)),
base,
index, value, graph()->start(), graph()->start());
}
+
// Arithmetic Operations.
Node* WordAnd(Node* a, Node* b) {
return NewNode(machine()->WordAnd(), a, b);
@@ -464,11 +481,6 @@ class RawMachineAssembler {
return
HeapConstant(isolate()->factory()->InternalizeUtf8String(string));
}
- // Control flow.
- void Goto(Label* label);
- void Branch(Node* condition, Label* true_val, Label* false_val);
- void Switch(Node* index, Label* default_label, int32_t* case_values,
- Label** case_labels, size_t case_count);
// Call through CallFunctionStub with lazy deopt and frame-state.
Node* CallFunctionStub0(Node* function, Node* receiver, Node* context,
Node* frame_state, CallFunctionFlags flags);
@@ -495,6 +507,16 @@ class RawMachineAssembler {
MachineType arg7_type, Node* function, Node* arg0,
Node* arg1, Node* arg2, Node* arg3, Node* arg4,
Node* arg5, Node* arg6, Node* arg7);
+
+ //
===========================================================================
+ // The following utility methods deal with control flow, hence might
switch
+ // the current basic block or create new basic blocks for labels.
+
+ // Control flow.
+ void Goto(Label* label);
+ void Branch(Node* condition, Label* true_val, Label* false_val);
+ void Switch(Node* index, Label* default_label, int32_t* case_values,
+ Label** case_labels, size_t case_count);
void Return(Node* value);
void Bind(Label* label);
void Deoptimize(Node* state);
@@ -510,8 +532,10 @@ class RawMachineAssembler {
return NewNode(common()->Phi(type, 4), n1, n2, n3, n4);
}
- // MachineAssembler is invalid after export.
- Schedule* Export();
+ //
===========================================================================
+ // The following generic node creation methods can be used for operators
that
+ // are not covered by the above utility methods. There should rarely be
a need
+ // to do that outside of testing though.
Node* NewNode(const Operator* op) {
return MakeNode(op, 0, static_cast<Node**>(NULL));
@@ -551,17 +575,8 @@ class RawMachineAssembler {
return MakeNode(op, value_input_count, value_inputs);
}
- protected:
- Node* MakeNode(const Operator* op, int input_count, Node** inputs);
-
- bool ScheduleValid() { return schedule_ != NULL; }
-
- Schedule* schedule() {
- DCHECK(ScheduleValid());
- return schedule_;
- }
-
private:
+ Node* MakeNode(const Operator* op, int input_count, Node** inputs);
BasicBlock* Use(Label* label);
BasicBlock* EnsureBlock(Label* label);
BasicBlock* CurrentBlock();
--
--
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