[ORC] Propagate weak & hidden flags when creating lazy reexports, redirectables.

Updates JITLinkRedirectableSymbolManager to take alias flags into account when
setting the scope and linkage of the created stubs (weak aliases get now get weak
linkage, hidden stubs get hidden visibility).

Updates lazyReexports to propagate alias flags (rather than trampoline flags)
when building the initial destinations map for the redirectable symbols manager.

Together these changes allow the LazyObjectLinkingLayer to link objects
containing weak and hidden symbols.

Author: lhames

compiler-rt/test/orc/TestCases/Generic/Inputs/bar-ret-void-weak.ll

@@ -0,0 +1,4 @@
+define weak void @bar()  {
+entry:
+  ret void
+}

compiler-rt/test/orc/TestCases/Generic/Inputs/baz-ret-void-hidden.ll

@@ -0,0 +1,4 @@
+define hidden void @baz()  {
+entry:
+  ret void
+}

compiler-rt/test/orc/TestCases/Generic/lazy-link.ll

@@ -6,9 +6,11 @@
 ; RUN: rm -rf %t && mkdir -p %t
 ; RUN: %clang -c -o %t/foo.o %S/Inputs/foo-ret-42.ll
 ; RUN: %clang -c -o %t/x.o %S/Inputs/var-x-42.ll
+; RUN: %clang -c -o %t/bar.o %S/Inputs/bar-ret-void-weak.ll
+; RUN: %clang -c -o %t/baz.o %S/Inputs/baz-ret-void-hidden.ll
 ; RUN: %clang -c -o %t/main.o %s
 ; RUN: %llvm_jitlink -noexec -show-linked-files %t/main.o -lazy %t/foo.o \
-; RUN:     -lazy %t/x.o | FileCheck %s
+; RUN:     -lazy %t/x.o -lazy %t/bar.o -lazy %t/baz.o | FileCheck %s
 ;
 ; UNSUPPORTED: system-windows
 ; REQUIRES: target={{(arm|aarch|x86_)64.*}}
@@ -21,9 +23,15 @@
 declare i32 @foo()
 @x = external global i32
 
+declare void @bar()
+declare hidden void @baz()
+
+
 define i32 @main(i32 %argc, ptr %argv) {
 entry:
   %foo_result = call i32 @foo()
+  call void @bar()
+  call void @baz()
   %x_val = load i32, ptr @x
   %result = add nsw i32 %foo_result, %x_val
   ret i32 %result

llvm/lib/ExecutionEngine/Orc/JITLinkRedirectableSymbolManager.cpp

@@ -47,7 +47,10 @@ void JITLinkRedirectableSymbolManager::emitRedirectableSymbols(
     Ptr.setScope(jitlink::Scope::Hidden);
     auto &Stub = PtrJumpStubCreator(*G, StubsSection, Ptr);
     Stub.setName(Name);
-    Stub.setScope(jitlink::Scope::Default);
+    Stub.setScope(Def.getFlags().isExported() ? jitlink::Scope::Default
+                                              : jitlink::Scope::Hidden);
+    Stub.setLinkage(!Def.getFlags().isWeak() ? jitlink::Linkage::Strong
+                                             : jitlink::Linkage::Weak);
     NewSymbols[std::move(PtrName)] = JITSymbolFlags();
   }
 

llvm/lib/ExecutionEngine/Orc/LazyReexports.cpp

@@ -387,7 +387,7 @@ void LazyReexportsManager::emitRedirectableSymbols(
   SymbolMap Redirs;
   size_t I = 0;
   for (auto &[Name, AI] : Reexports)
-    Redirs[Name] = (*ReentryPoints)[I++];
+    Redirs[Name] = {(*ReentryPoints)[I++].getAddress(), AI.AliasFlags};
 
   I = 0;
   if (!Reexports.empty()) {