Move dllimport name mangling to IR mangler.

This ensures that LTO clients see the correct external symbol name.

Differential Revision: http://reviews.llvm.org/D10318

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239437 91177308-0d34-0410-b5e6-96231b3b80d8

lib/IR/Mangler.cpp

@@ -112,6 +112,10 @@ void Mangler::getNameWithPrefix(raw_ostream &OS, const GlobalValue *GV,
     return;
   }
 
+  // dllimported symbols have a __imp_ prefix.
+  if (GV->hasDLLImportStorageClass())
+    OS << "__imp_";
+
   StringRef Name = GV->getName();
   char Prefix = DL->getGlobalPrefix();
 

lib/Target/ARM/ARMAsmPrinter.cpp

@@ -851,16 +851,7 @@ MCSymbol *ARMAsmPrinter::GetARMGVSymbol(const GlobalValue *GV,
   } else if (Subtarget->isTargetCOFF()) {
     assert(Subtarget->isTargetWindows() &&
            "Windows is the only supported COFF target");
-
-    bool IsIndirect = (TargetFlags & ARMII::MO_DLLIMPORT);
-    if (!IsIndirect)
     return getSymbol(GV);
-
-    SmallString<128> Name;
-    Name = "__imp_";
-    getNameWithPrefix(Name, GV);
-
-    return OutContext.getOrCreateSymbol(Name);
   } else if (Subtarget->isTargetELF()) {
     return getSymbol(GV);
   }

lib/Target/ARM/ARMISelLowering.cpp

@@ -1751,11 +1751,8 @@ ARMTargetLowering::LowerCall(TargetLowering::CallLoweringInfo &CLI,
     } else if (Subtarget->isTargetCOFF()) {
       assert(Subtarget->isTargetWindows() &&
              "Windows is the only supported COFF target");
-      unsigned TargetFlags = GV->hasDLLImportStorageClass()
-                                 ? ARMII::MO_DLLIMPORT
-                                 : ARMII::MO_NO_FLAG;
       Callee = DAG.getTargetGlobalAddress(GV, dl, getPointerTy(), /*Offset=*/0,
-                                          TargetFlags);
+                                          ARMII::MO_NO_FLAG);
       if (GV->hasDLLImportStorageClass())
         Callee = DAG.getLoad(getPointerTy(), dl, DAG.getEntryNode(),
                              DAG.getNode(ARMISD::Wrapper, dl, getPointerTy(),
@@ -2646,8 +2643,6 @@ SDValue ARMTargetLowering::LowerGlobalAddressWindows(SDValue Op,
          "Windows on ARM expects to use movw/movt");
 
   const GlobalValue *GV = cast<GlobalAddressSDNode>(Op)->getGlobal();
-  const ARMII::TOF TargetFlags =
-    (GV->hasDLLImportStorageClass() ? ARMII::MO_DLLIMPORT : ARMII::MO_NO_FLAG);
   EVT PtrVT = getPointerTy();
   SDValue Result;
   SDLoc DL(Op);
@@ -2658,7 +2653,7 @@ SDValue ARMTargetLowering::LowerGlobalAddressWindows(SDValue Op,
   // operands, expand this into two nodes.
   Result = DAG.getNode(ARMISD::Wrapper, DL, PtrVT,
                        DAG.getTargetGlobalAddress(GV, DL, PtrVT, /*Offset=*/0,
-                                                  TargetFlags));
+                                                  ARMII::MO_NO_FLAG));
   if (GV->hasDLLImportStorageClass())
     Result = DAG.getLoad(PtrVT, DL, DAG.getEntryNode(), Result,
                          MachinePointerInfo::getGOT(), false, false, false, 0);

lib/Target/ARM/MCTargetDesc/ARMBaseInfo.h

@@ -297,17 +297,12 @@ namespace ARMII {
     /// just that part of the flag set.
     MO_OPTION_MASK = 0x3f,
 
-    /// MO_DLLIMPORT - On a symbol operand, this represents that the reference
-    /// to the symbol is for an import stub.  This is used for DLL import
-    /// storage class indication on Windows.
-    MO_DLLIMPORT = 0x40,
-
     /// MO_NONLAZY - This is an independent flag, on a symbol operand "FOO" it
     /// represents a symbol which, if indirect, will get special Darwin mangling
     /// as a non-lazy-ptr indirect symbol (i.e. "L_FOO$non_lazy_ptr"). Can be
     /// combined with MO_LO16, MO_HI16 or MO_NO_FLAG (in a constant-pool, for
     /// example).
-    MO_NONLAZY = 0x80,
+    MO_NONLAZY = 0x40,
 
     // It's undefined behaviour if an enum overflows the range between its
     // smallest and largest values, but since these are |ed together, it can

lib/Target/X86/X86AsmPrinter.cpp

@@ -94,11 +94,6 @@ static void printSymbolOperand(X86AsmPrinter &P, const MachineOperand &MO,
     else
       GVSym = P.getSymbol(GV);
 
-    // Handle dllimport linkage.
-    if (MO.getTargetFlags() == X86II::MO_DLLIMPORT)
-      GVSym =
-          P.OutContext.getOrCreateSymbol(Twine("__imp_") + GVSym->getName());
-
     if (MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY ||
         MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY_PIC_BASE) {
       MCSymbol *Sym = P.getSymbolWithGlobalValueBase(GV, "$non_lazy_ptr");

lib/Target/X86/X86MCInstLower.cpp

@@ -133,10 +133,6 @@ GetSymbolFromOperand(const MachineOperand &MO) const {
   StringRef Suffix;
 
   switch (MO.getTargetFlags()) {
-  case X86II::MO_DLLIMPORT:
-    // Handle dllimport linkage.
-    Name += "__imp_";
-    break;
   case X86II::MO_DARWIN_STUB:
     Suffix = "$stub";
     break;

test/Object/dllimport.ll

@@ -0,0 +1,17 @@
+; RUN: llvm-as %s -o - | llvm-nm - | FileCheck %s
+
+target datalayout = "e-m:w-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-pc-windows-msvc"
+
+; CHECK: U __imp_f
+; CHECK: U __imp_v
+; CHECK: T g
+
+declare dllimport void @f()
+@v = external dllimport global i32
+
+define void @g() {
+  call void @f()
+  store i32 42, i32* @v
+  ret void
+}