Attribute nonlazybind should not affect calls to functions with hidden visibility.

Differential Revision: https://reviews.llvm.org/D39625

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@317639 91177308-0d34-0410-b5e6-96231b3b80d8

Author: tmsri

lib/Target/TargetMachine.cpp

@@ -167,6 +167,13 @@ bool TargetMachine::shouldAssumeDSOLocal(const Module &M,
     if (GV && !GV->isDeclarationForLinker())
       return true;
 
+    // A symbol marked nonlazybind should not be accessed with a plt. If the
+    // symbol turns out to be external, the linker will convert a direct
+    // access to an access via the plt, so don't assume it is local.
+    const Function *F = dyn_cast_or_null<Function>(GV);
+    if (F && F->hasFnAttribute(Attribute::NonLazyBind))
+      return false;
+
     bool IsTLS = GV && GV->isThreadLocal();
     bool IsAccessViaCopyRelocs =
         Options.MCOptions.MCPIECopyRelocations && GV && isa<GlobalVariable>(GV);

lib/Target/X86/X86Subtarget.cpp

@@ -144,15 +144,6 @@ X86Subtarget::classifyGlobalFunctionReference(const GlobalValue *GV) const {
 unsigned char
 X86Subtarget::classifyGlobalFunctionReference(const GlobalValue *GV,
                                               const Module &M) const {
-  const Function *F = dyn_cast_or_null<Function>(GV);
-
-  // Do not use the PLT when explicitly told to do so for ELF 64-bit
-  // target.
-  if (isTargetELF() && is64Bit() && F &&
-      F->hasFnAttribute(Attribute::NonLazyBind) &&
-      GV->isDeclarationForLinker())
-    return X86II::MO_GOTPCREL;
-
   if (TM.shouldAssumeDSOLocal(M, GV))
     return X86II::MO_NO_FLAG;
 
@@ -162,12 +153,16 @@ X86Subtarget::classifyGlobalFunctionReference(const GlobalValue *GV,
     return X86II::MO_DLLIMPORT;
   }
 
+  const Function *F = dyn_cast_or_null<Function>(GV);
+
   if (isTargetELF()) {
     if (is64Bit() && F && (CallingConv::X86_RegCall == F->getCallingConv()))
       // According to psABI, PLT stub clobbers XMM8-XMM15.
       // In Regcall calling convention those registers are used for passing
       // parameters. Thus we need to prevent lazy binding in Regcall.
       return X86II::MO_GOTPCREL;
+    if (F && F->hasFnAttribute(Attribute::NonLazyBind) && is64Bit())
+      return X86II::MO_GOTPCREL;
     return X86II::MO_PLT;
   }
 

test/CodeGen/X86/no-plt.ll

@@ -6,12 +6,14 @@
 define i32 @main() #0 {
 ; X64: callq *_Z3foov@GOTPCREL(%rip)
 ; X64: callq _Z3barv
+; X64: callq _Z3bazv
 
 entry:
   %retval = alloca i32, align 4
   store i32 0, i32* %retval, align 4
   %call1 = call i32 @_Z3foov()
   %call2 = call i32 @_Z3barv()
+  %call3 = call i32 @_Z3bazv()
   ret i32 0
 }
 
@@ -20,4 +22,9 @@ declare i32 @_Z3foov() #1
 
 declare i32 @_Z3barv() #2
 
+; Function Attrs: nonlazybind
+declare hidden i32 @_Z3bazv() #3
+
+
 attributes #1 = { nonlazybind }
+attributes #3 = { nonlazybind }