Initial Subzero WASM prototype.

src/IceCfgNode.cpp

Index: src/IceCfgNode.cpp
diff --git a/src/IceCfgNode.cpp b/src/IceCfgNode.cpp
index a87642d14c78a72370a6cd4393dfd8c3bc3141a0..059fef9066148401a1685117d35edd740e6c5d52 100644
--- a/src/IceCfgNode.cpp
+++ b/src/IceCfgNode.cpp
@@ -37,10 +37,22 @@ CfgNode::CfgNode(Cfg *Func, SizeT Number) : Func(Func), Number(Number) {
 
 // Adds an instruction to either the Phi list or the regular instruction list.
 // Validates that all Phis are added before all regular instructions.
-void CfgNode::appendInst(Inst *Instr) {
+void CfgNode::appendInst(Inst *Instr, bool AllowPhisAnywhere) {
   ++InstCountEstimate;
+
+  if (auto *Br = llvm::dyn_cast<InstBr>(Instr)) {

[Jim Stichnoth, 2016/04/04 21:26:51]

You may also want to do the same for switch instructions.

If it's a branch or switch (or any other terminator instruction), you could
iterate over Instr->getTerminatorEdges() and add the out-edges.

Also, I think it would be better if this block were guarded on wasm, e.g.
BuildDefs::wasm(), or getFlags().wasm() or whatever it's called.

[Eric Holk, 2016/04/04 22:23:22]

Done.

+    if (auto *N = Br->getTargetTrue()) {
+      N->addInEdge(this);
+      addOutEdge(N);
+    }
+    if (auto *N = Br->getTargetFalse()) {
+      N->addInEdge(this);
+      addOutEdge(N);
+    }
+  }
+
   if (auto *Phi = llvm::dyn_cast<InstPhi>(Instr)) {
-    if (!Insts.empty()) {
+    if (!AllowPhisAnywhere && !Insts.empty()) {
       Func->setError("Phi instruction added to the middle of a block");
       return;
     }
@@ -81,6 +93,8 @@ void CfgNode::computePredecessors() {
 }
 
 void CfgNode::computeSuccessors() {
+  OutEdges.clear();
+  InEdges.clear();
   OutEdges = Insts.rbegin()->getTerminatorEdges();
 }
 
@@ -882,7 +896,7 @@ void CfgNode::contractIfEmpty() {
   // Make sure there is actually a successor to repoint in-edges to.
   if (OutEdges.empty())
     return;
-  assert(OutEdges.size() == 1);
+  assert(hasSingleOutEdge());
   // Don't try to delete a self-loop.
   if (OutEdges[0] == this)
     return;