Don't try to check all uses if lazy loading.

This means that LTO_SYMBOL_SCOPE_DEFAULT_CAN_BE_HIDDEN will not be set
in a few cases.

This should have no impact in ld64 since it doesn't use lazy loading
when merging modules and that is when it checks
LTO_SYMBOL_SCOPE_DEFAULT_CAN_BE_HIDDEN.

llvm-svn: 257915

llvm/lib/CodeGen/Analysis.cpp

@@ -639,6 +639,11 @@ bool llvm::canBeOmittedFromSymbolTable(const GlobalValue *GV) {
   if (isa<GlobalAlias>(GV))
     return false;
 
+  // If we don't see every use, we have to be conservative and assume the value
+  // address is significant.
+  if (GV->getParent()->getMaterializer())
+    return false;
+
   GlobalStatus GS;
   if (GlobalStatus::analyzeGlobal(GV, GS))
     return false;

llvm/test/LTO/X86/pr25919.ll

@@ -0,0 +1,11 @@
+; RUN: llvm-as < %s >%t1
+; RUN: llvm-lto -list-symbols-only %t1 | FileCheck %s
+
+; This tests that we don't crash trying to find all uses in a lazily loaded
+; module.
+; CHECK: foo
+
+target triple = "x86_64-unknown-linux-gnu"
+define linkonce_odr void @foo() {
+  ret void
+}