Revision: 16857
Author: [email protected]
Date: Fri Sep 20 10:47:09 2013 UTC
Log: Allow IfBuilder's to join existing (captured) continuations.
[email protected]
Review URL: https://codereview.chromium.org/23452049
http://code.google.com/p/v8/source/detail?r=16857
Modified:
/branches/bleeding_edge/src/hydrogen.cc
/branches/bleeding_edge/src/hydrogen.h
=======================================
--- /branches/bleeding_edge/src/hydrogen.cc Fri Sep 20 09:27:40 2013 UTC
+++ /branches/bleeding_edge/src/hydrogen.cc Fri Sep 20 10:47:09 2013 UTC
@@ -804,6 +804,28 @@
captured_ = true;
End();
}
+
+
+void HGraphBuilder::IfBuilder::JoinContinuation(HIfContinuation*
continuation) {
+ ASSERT(!finished_);
+ ASSERT(!captured_);
+ HBasicBlock* true_block = last_true_block_ == NULL
+ ? first_true_block_
+ : last_true_block_;
+ HBasicBlock* false_block = did_else_ && (first_false_block_ != NULL)
+ ? builder_->current_block()
+ : first_false_block_;
+ if (true_block != NULL && !true_block->IsFinished()) {
+ ASSERT(continuation->IsTrueReachable());
+ true_block->GotoNoSimulate(continuation->true_branch());
+ }
+ if (false_block != NULL && !false_block->IsFinished()) {
+ ASSERT(continuation->IsFalseReachable());
+ false_block->GotoNoSimulate(continuation->false_branch());
+ }
+ captured_ = true;
+ End();
+}
void HGraphBuilder::IfBuilder::Then() {
=======================================
--- /branches/bleeding_edge/src/hydrogen.h Fri Sep 20 09:25:10 2013 UTC
+++ /branches/bleeding_edge/src/hydrogen.h Fri Sep 20 10:47:09 2013 UTC
@@ -941,7 +941,12 @@
class HIfContinuation V8_FINAL {
public:
- HIfContinuation() { continuation_captured_ = false; }
+ HIfContinuation() : continuation_captured_(false) {}
+ HIfContinuation(HBasicBlock* true_branch,
+ HBasicBlock* false_branch,
+ int position = RelocInfo::kNoPosition)
+ : continuation_captured_(true), true_branch_(true_branch),
+ false_branch_(false_branch), position_(position) {}
~HIfContinuation() { ASSERT(!continuation_captured_); }
void Capture(HBasicBlock* true_branch,
@@ -970,6 +975,10 @@
return IsTrueReachable() || IsFalseReachable();
}
+ HBasicBlock* true_branch() const { return true_branch_; }
+ HBasicBlock* false_branch() const { return false_branch_; }
+
+ private:
bool continuation_captured_;
HBasicBlock* true_branch_;
HBasicBlock* false_branch_;
@@ -1380,8 +1389,50 @@
void Or();
void And();
+ // Captures the current state of this IfBuilder in the specified
+ // continuation and ends this IfBuilder.
void CaptureContinuation(HIfContinuation* continuation);
+ // Joins the specified continuation from this IfBuilder and ends this
+ // IfBuilder. This appends a Goto instruction from the true branch of
+ // this IfBuilder to the true branch of the continuation unless the
+ // true branch of this IfBuilder is already finished. And vice versa
+ // for the false branch.
+ //
+ // The basic idea is as follows: You have several nested IfBuilder's
+ // that you want to join based on two possible outcomes (i.e. success
+ // and failure, or whatever). You can do this easily using this method
+ // now, for example:
+ //
+ // HIfContinuation cont(graph()->CreateBasicBlock(),
+ // graph()->CreateBasicBlock());
+ // ...
+ // IfBuilder if_whatever(this);
+ // if_whatever.If<Condition>(arg);
+ // if_whatever.Then();
+ // ...
+ // if_whatever.Else();
+ // ...
+ // if_whatever.JoinContinuation(&cont);
+ // ...
+ // IfBuilder if_something(this);
+ // if_something.If<Condition>(arg1, arg2);
+ // if_something.Then();
+ // ...
+ // if_something.Else();
+ // ...
+ // if_something.JoinContinuation(&cont);
+ // ...
+ // IfBuilder if_finally(this, &cont);
+ // if_finally.Then();
+ // // continues after then code of if_whatever or if_something.
+ // ...
+ // if_finally.Else();
+ // // continues after else code of if_whatever or if_something.
+ // ...
+ // if_finally.End();
+ void JoinContinuation(HIfContinuation* continuation);
+
void Then();
void Else();
void End();
--
--
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