Avoid JIT recursive compilation

[yaron.keren]

Summary

JITEmitter::getPointerToGlobal is called while in compilation, it should not call upon TheJIT->getPointerToGlobal since it may start another recursive compilation. Instead, it should call itself and generate a stub.

[yaron.keren]

Recursion not needed, just get the aliasee and continue.

[yaron.keren]

Calling getSimpleAliasee twice is not needed either.

[yaron.keren]

JIT gone.

[yaron.keren]

JIT gone.

lib/ExecutionEngine/JIT/JITEmitter.cpp

 
   if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V)) {
     // We can only handle simple cases.
-    if (GlobalValue *GV = getSimpleAliasee(GA->getAliasee()))
-      return TheJIT->getPointerToGlobal(GV);
+    V = getSimpleAliasee(GA->getAliasee());
+    if (!V)
       return nullptr;
   }
 
   // If we have already compiled the function, return a pointer to its body.

test/ExecutionEngine/test-alias.ll

+; RUN: %lli %s > /dev/null
+
+%class.C = type { i32 (...)** }
+
+@_ZN1CD1Ev = alias void (%class.C*)* @_ZN1CD2Ev
+
+define x86_thiscallcc void @_ZN1CD2Ev(%class.C* %this) unnamed_addr #0 align 2 {
+entry:
+  %this.addr = alloca %class.C*, align 4
+  store %class.C* %this, %class.C** %this.addr, align 4
+  %this1 = load %class.C** %this.addr
+  ret void
+}
+
+define i32 @main() #1 {
+entry:
+  %retval = alloca i32, align 4
+  %c = alloca %class.C, align 4
+  call x86_thiscallcc void @_ZN1CD1Ev(%class.C* %c)
+  store i32 0, i32* %retval
+  %0 = load i32* %retval
+  ret i32 %0
+}