AArch64: put nonlazybind special handling behind a flag for now.

It's basically a terrible idea anyway but objc_msgSend gets emitted like that.
We can decide on a better way to deal with it in the unlikely event that anyone
actually uses it.

llvm-svn: 300474

Author: TNorthover

llvm/lib/Target/AArch64/AArch64Subtarget.cpp

@@ -35,6 +35,11 @@ static cl::opt<bool>
 UseAddressTopByteIgnored("aarch64-use-tbi", cl::desc("Assume that top byte of "
                          "an address is ignored"), cl::init(false), cl::Hidden);
 
+static cl::opt<bool>
+    UseNonLazyBind("aarch64-enable-nonlazybind",
+                   cl::desc("Call nonlazybind functions via direct GOT load"),
+                   cl::init(false), cl::Hidden);
+
 AArch64Subtarget &
 AArch64Subtarget::initializeSubtargetDependencies(StringRef FS,
                                                   StringRef CPUString) {
@@ -165,7 +170,7 @@ unsigned char AArch64Subtarget::classifyGlobalFunctionReference(
 
   // NonLazyBind goes via GOT unless we know it's available locally.
   auto *F = dyn_cast<Function>(GV);
-  if (F && F->hasFnAttribute(Attribute::NonLazyBind) &&
+  if (UseNonLazyBind && F && F->hasFnAttribute(Attribute::NonLazyBind) &&
       !TM.shouldAssumeDSOLocal(*GV->getParent(), GV))
     return AArch64II::MO_GOT;
 

llvm/test/CodeGen/AArch64/nonlazybind.ll

@@ -1,4 +1,5 @@
-; RUN: llc -mtriple=aarch64-apple-ios %s -o - | FileCheck %s
+; RUN: llc -mtriple=aarch64-apple-ios %s -o - -aarch64-enable-nonlazybind | FileCheck %s
+; RUN: llc -mtriple=aarch64-apple-ios %s -o - | FileCheck %s --check-prefix=CHECK-NORMAL
 
 define void @local() nonlazybind {
   ret void
@@ -15,6 +16,10 @@ define void @test_laziness() {
 ; CHECK: ldr [[FUNC:x[0-9]+]], [x[[TMP]], _nonlocal@GOTPAGEOFF]
 ; CHECK: blr [[FUNC]]
 
+; CHECK-NORMAL-LABEL: test_laziness:
+; CHECK-NORMAL: bl _local
+; CHEKC-NORMAL: bl _nonlocal
+
   call void @local()
   call void @nonlocal()
   ret void
@@ -27,6 +32,9 @@ define void @test_laziness_tail() {
 ; CHECK: ldr [[FUNC:x[0-9]+]], [x[[TMP]], _nonlocal@GOTPAGEOFF]
 ; CHECK: br [[FUNC]]
 
+; CHECK-NORMAL-LABEL: test_laziness_tail:
+; CHECK-NORMAL: b _nonlocal
+
   tail call void @nonlocal()
   ret void
 }