Handle weak_extern in the JIT. This fixes

SingleSource/UnitTests/2007-04-25-weak.c in JIT mode. The test
now passes on systems which are able to produce a correct
reference output to compare with.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61674 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 8 insertions, 2 deletions

diff --git a/lib/ExecutionEngine/JIT/JITEmitter.cpp b/lib/ExecutionEngine/JIT/JITEmitter.cpp
index e041767f8f..3f3f681f61 100644
--- a/lib/ExecutionEngine/JIT/JITEmitter.cpp
+++ b/lib/ExecutionEngine/JIT/JITEmitter.cpp
@@ -177,9 +177,14 @@ void *JITResolver::getFunctionStub(Function *F) {
   // Call the lazy resolver function unless we already KNOW it is an external
   // function, in which case we just skip the lazy resolution step.
   void *Actual = (void*)(intptr_t)LazyResolverFn;
-  if (F->isDeclaration() && !F->hasNotBeenReadFromBitcode())
+  if (F->isDeclaration() && !F->hasNotBeenReadFromBitcode()) {
     Actual = TheJIT->getPointerToFunction(F);
 
+    // If we resolved the symbol to a null address (eg. a weak external)
+    // don't emit a stub. Return a null pointer to the application.
+    if (!Actual) return 0;
+  }
+
   // Otherwise, codegen a new stub.  For now, the stub will call the lazy
   // resolver function.
   Stub = TheJIT->getJITInfo().emitFunctionStub(F, Actual,
@@ -905,7 +910,8 @@ bool JITEmitter::finishFunction(MachineFunction &F) {
       void *ResultPtr = 0;
       if (!MR.letTargetResolve()) {
         if (MR.isExternalSymbol()) {
-          ResultPtr = TheJIT->getPointerToNamedFunction(MR.getExternalSymbol());
+          ResultPtr = TheJIT->getPointerToNamedFunction(MR.getExternalSymbol(),
+                                                        false);
           DOUT << "JIT: Map \'" << MR.getExternalSymbol() << "\' to ["
                << ResultPtr << "]\n";