Reaching Definitions Analysis for LocalGraph (#5817)

This change implements a reaching definitions analysis which is intended
to be equivalent to the information provided by LocalGraph, specifically
the Flower class of LocalGraph.

It also introduces a CRTP utility in visitor-transfer-function.h which
implements most commonly found visitor-type transfer function
functionalities. The MonotoneCFGAnalyzer is also modified to add a phase
to collect results after the analysis is solved from the final CFG
states.

1 files changed, 7 insertions, 11 deletions

diff --git a/src/analysis/cfg-impl.h b/src/analysis/cfg-impl.h
index cf348fa09..14fadd22c 100644
--- a/src/analysis/cfg-impl.h
+++ b/src/analysis/cfg-impl.h
@@ -118,21 +118,17 @@ template<typename T> struct _indirect_ptr_vec {
   iterator end() const { return {&vec.data()[vec.size()]}; }
 };
 
-struct BasicBlock::Predecessors : _indirect_ptr_vec<BasicBlock> {
-  Predecessors(const BasicBlock& block)
-    : _indirect_ptr_vec(block.predecessors) {}
+struct BasicBlock::BasicBlockIterable : _indirect_ptr_vec<BasicBlock> {
+  BasicBlockIterable(const std::vector<BasicBlock*>& blocks)
+    : _indirect_ptr_vec(blocks) {}
 };
 
-struct BasicBlock::Successors : _indirect_ptr_vec<BasicBlock> {
-  Successors(const BasicBlock& block) : _indirect_ptr_vec(block.successors) {}
-};
-
-inline BasicBlock::Predecessors BasicBlock::preds() const {
-  return Predecessors(*this);
+inline BasicBlock::BasicBlockIterable BasicBlock::preds() const {
+  return BasicBlockIterable(predecessors);
 }
 
-inline BasicBlock::Successors BasicBlock::succs() const {
-  return Successors(*this);
+inline BasicBlock::BasicBlockIterable BasicBlock::succs() const {
+  return BasicBlockIterable(successors);
 }
 
 } // namespace wasm::analysis