Revert r301040 "X86: Don't emit zero-byte functions on Windows"

This broke almost all bots. Reverting while fixing.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@301041 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/llvm/Target/TargetInstrInfo.h b/include/llvm/Target/TargetInstrInfo.h
index 82a682c..0dc9cf7 100644 (file)
--- a/include/llvm/Target/TargetInstrInfo.h
+++ b/include/llvm/Target/TargetInstrInfo.h
@@ -1108,7 +1108,7 @@ public:
 
 
   /// Return the noop instruction to use for a noop.
-  virtual void getNoop(MCInst &NopInst) const;
+  virtual void getNoopForMachoTarget(MCInst &NopInst) const;
 
   /// Return true for post-incremented instructions.
   virtual bool isPostIncrement(const MachineInstr &MI) const {

diff --git a/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index bf2e581..028c79f 100644 (file)
--- a/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -1046,17 +1046,15 @@ void AsmPrinter::EmitFunctionBody() {
   // If the function is empty and the object file uses .subsections_via_symbols,
   // then we need to emit *something* to the function body to prevent the
   // labels from collapsing together.  Just emit a noop.
-  // Similarly, don't emit empty functions on Windows either. It can lead to
-  // duplicate entries (two functions with the same RVA) in the Guard CF Table
-  // after linking, causing the kernel not to load the binary:
-  // https://developercommunity.visualstudio.com/content/problem/45366/vc-linker-creates-invalid-dll-with-clang-cl.html
-  // FIXME: Hide this behind some API in e.g. MCAsmInfo or MCTargetStreamer.
-  if (!HasAnyRealCode &&
-      (MAI->hasSubsectionsViaSymbols() || TM.getTargetTriple().isOSWindows())) {
+  if ((MAI->hasSubsectionsViaSymbols() && !HasAnyRealCode)) {
     MCInst Noop;
-    MF->getSubtarget().getInstrInfo()->getNoop(Noop);
+    MF->getSubtarget().getInstrInfo()->getNoopForMachoTarget(Noop);
     OutStreamer->AddComment("avoids zero-length function");
-    OutStreamer->EmitInstruction(Noop, getSubtargetInfo());
+
+    // Targets can opt-out of emitting the noop here by leaving the opcode
+    // unspecified.
+    if (Noop.getOpcode())
+      OutStreamer->EmitInstruction(Noop, getSubtargetInfo());
   }
 
   const Function *F = MF->getFunction();

diff --git a/lib/CodeGen/TargetInstrInfo.cpp b/lib/CodeGen/TargetInstrInfo.cpp
index 69b2517..711144a 100644 (file)
--- a/lib/CodeGen/TargetInstrInfo.cpp
+++ b/lib/CodeGen/TargetInstrInfo.cpp
@@ -428,8 +428,8 @@ static const TargetRegisterClass *canFoldCopy(const MachineInstr &MI,
   return nullptr;
 }
 
-void TargetInstrInfo::getNoop(MCInst &NopInst) const {
-  llvm_unreachable("Not implemented");
+void TargetInstrInfo::getNoopForMachoTarget(MCInst &NopInst) const {
+  llvm_unreachable("Not a MachO target");
 }
 
 static MachineInstr *foldPatchpoint(MachineFunction &MF, MachineInstr &MI,

diff --git a/lib/Target/AArch64/AArch64InstrInfo.cpp b/lib/Target/AArch64/AArch64InstrInfo.cpp
index 57ff463..41fc8ec 100644 (file)
--- a/lib/Target/AArch64/AArch64InstrInfo.cpp
+++ b/lib/Target/AArch64/AArch64InstrInfo.cpp
@@ -3025,7 +3025,7 @@ bool llvm::rewriteAArch64FrameIndex(MachineInstr &MI, unsigned FrameRegIdx,
   return false;
 }
 
-void AArch64InstrInfo::getNoop(MCInst &NopInst) const {
+void AArch64InstrInfo::getNoopForMachoTarget(MCInst &NopInst) const {
   NopInst.setOpcode(AArch64::HINT);
   NopInst.addOperand(MCOperand::createImm(0));
 }

diff --git a/lib/Target/AArch64/AArch64InstrInfo.h b/lib/Target/AArch64/AArch64InstrInfo.h
index 4cd14db..bacce44 100644 (file)
--- a/lib/Target/AArch64/AArch64InstrInfo.h
+++ b/lib/Target/AArch64/AArch64InstrInfo.h
@@ -205,7 +205,7 @@ public:
                     const DebugLoc &DL, unsigned DstReg,
                     ArrayRef<MachineOperand> Cond, unsigned TrueReg,
                     unsigned FalseReg) const override;
-  void getNoop(MCInst &NopInst) const override;
+  void getNoopForMachoTarget(MCInst &NopInst) const override;
 
   /// analyzeCompare - For a comparison instruction, return the source registers
   /// in SrcReg and SrcReg2, and the value it compares against in CmpValue.

diff --git a/lib/Target/ARM/ARMBaseInstrInfo.h b/lib/Target/ARM/ARMBaseInstrInfo.h
index 28c407f..faf1c63 100644 (file)
--- a/lib/Target/ARM/ARMBaseInstrInfo.h
+++ b/lib/Target/ARM/ARMBaseInstrInfo.h
@@ -105,6 +105,10 @@ public:
   // Return whether the target has an explicit NOP encoding.
   bool hasNOP() const;
 
+  virtual void getNoopForElfTarget(MCInst &NopInst) const {
+    getNoopForMachoTarget(NopInst);
+  }
+
   // Return the non-pre/post incrementing version of 'Opc'. Return 0
   // if there is not such an opcode.
   virtual unsigned getUnindexedOpcode(unsigned Opc) const = 0;

diff --git a/lib/Target/ARM/ARMInstrInfo.cpp b/lib/Target/ARM/ARMInstrInfo.cpp
index a0e2ac4..3b3606e 100644 (file)
--- a/lib/Target/ARM/ARMInstrInfo.cpp
+++ b/lib/Target/ARM/ARMInstrInfo.cpp
@@ -32,8 +32,8 @@ using namespace llvm;
 ARMInstrInfo::ARMInstrInfo(const ARMSubtarget &STI)
     : ARMBaseInstrInfo(STI), RI() {}
 
-/// Return the noop instruction to use for a noop.
-void ARMInstrInfo::getNoop(MCInst &NopInst) const {
+/// getNoopForMachoTarget - Return the noop instruction to use for a noop.
+void ARMInstrInfo::getNoopForMachoTarget(MCInst &NopInst) const {
   if (hasNOP()) {
     NopInst.setOpcode(ARM::HINT);
     NopInst.addOperand(MCOperand::createImm(0));

diff --git a/lib/Target/ARM/ARMInstrInfo.h b/lib/Target/ARM/ARMInstrInfo.h
index c87fb97..4b1b709 100644 (file)
--- a/lib/Target/ARM/ARMInstrInfo.h
+++ b/lib/Target/ARM/ARMInstrInfo.h
@@ -25,8 +25,8 @@ class ARMInstrInfo : public ARMBaseInstrInfo {
 public:
   explicit ARMInstrInfo(const ARMSubtarget &STI);
 
-  /// Return the noop instruction to use for a noop.
-  void getNoop(MCInst &NopInst) const override;
+  /// getNoopForMachoTarget - Return the noop instruction to use for a noop.
+  void getNoopForMachoTarget(MCInst &NopInst) const override;
 
   // Return the non-pre/post incrementing version of 'Opc'. Return 0
   // if there is not such an opcode.

diff --git a/lib/Target/ARM/ARMMCInstLower.cpp b/lib/Target/ARM/ARMMCInstLower.cpp
index 9e9c1ba..0fd9826 100644 (file)
--- a/lib/Target/ARM/ARMMCInstLower.cpp
+++ b/lib/Target/ARM/ARMMCInstLower.cpp
@@ -211,9 +211,11 @@ void ARMAsmPrinter::EmitSled(const MachineInstr &MI, SledKind Kind)
     .addImm(ARMCC::AL).addReg(0));
 
   MCInst Noop;
-  Subtarget->getInstrInfo()->getNoop(Noop);
+  Subtarget->getInstrInfo()->getNoopForElfTarget(Noop);
   for (int8_t I = 0; I < NoopsInSledCount; I++)
+  {
     OutStreamer->EmitInstruction(Noop, getSubtargetInfo());
+  }
 
   OutStreamer->EmitLabel(Target);
   recordSled(CurSled, MI, Kind);

diff --git a/lib/Target/ARM/Thumb1InstrInfo.cpp b/lib/Target/ARM/Thumb1InstrInfo.cpp
index 0ebf559..27bff4d 100644 (file)
--- a/lib/Target/ARM/Thumb1InstrInfo.cpp
+++ b/lib/Target/ARM/Thumb1InstrInfo.cpp
@@ -24,8 +24,8 @@ using namespace llvm;
 Thumb1InstrInfo::Thumb1InstrInfo(const ARMSubtarget &STI)
     : ARMBaseInstrInfo(STI), RI() {}
 
-/// Return the noop instruction to use for a noop.
-void Thumb1InstrInfo::getNoop(MCInst &NopInst) const {
+/// getNoopForMachoTarget - Return the noop instruction to use for a noop.
+void Thumb1InstrInfo::getNoopForMachoTarget(MCInst &NopInst) const {
   NopInst.setOpcode(ARM::tMOVr);
   NopInst.addOperand(MCOperand::createReg(ARM::R8));
   NopInst.addOperand(MCOperand::createReg(ARM::R8));

diff --git a/lib/Target/ARM/Thumb1InstrInfo.h b/lib/Target/ARM/Thumb1InstrInfo.h
index e8d9a9c..931914a 100644 (file)
--- a/lib/Target/ARM/Thumb1InstrInfo.h
+++ b/lib/Target/ARM/Thumb1InstrInfo.h
@@ -25,8 +25,8 @@ class Thumb1InstrInfo : public ARMBaseInstrInfo {
 public:
   explicit Thumb1InstrInfo(const ARMSubtarget &STI);
 
-  /// Return the noop instruction to use for a noop.
-  void getNoop(MCInst &NopInst) const override;
+  /// getNoopForMachoTarget - Return the noop instruction to use for a noop.
+  void getNoopForMachoTarget(MCInst &NopInst) const override;
 
   // Return the non-pre/post incrementing version of 'Opc'. Return 0
   // if there is not such an opcode.

diff --git a/lib/Target/ARM/Thumb2InstrInfo.cpp b/lib/Target/ARM/Thumb2InstrInfo.cpp
index 2e2dfe0..818ba85 100644 (file)
--- a/lib/Target/ARM/Thumb2InstrInfo.cpp
+++ b/lib/Target/ARM/Thumb2InstrInfo.cpp
@@ -32,8 +32,8 @@ OldT2IfCvt("old-thumb2-ifcvt", cl::Hidden,
 Thumb2InstrInfo::Thumb2InstrInfo(const ARMSubtarget &STI)
     : ARMBaseInstrInfo(STI), RI() {}
 
-/// Return the noop instruction to use for a noop.
-void Thumb2InstrInfo::getNoop(MCInst &NopInst) const {
+/// getNoopForMachoTarget - Return the noop instruction to use for a noop.
+void Thumb2InstrInfo::getNoopForMachoTarget(MCInst &NopInst) const {
   NopInst.setOpcode(ARM::tHINT);
   NopInst.addOperand(MCOperand::createImm(0));
   NopInst.addOperand(MCOperand::createImm(ARMCC::AL));

diff --git a/lib/Target/ARM/Thumb2InstrInfo.h b/lib/Target/ARM/Thumb2InstrInfo.h
index c834ba7..15d6330 100644 (file)
--- a/lib/Target/ARM/Thumb2InstrInfo.h
+++ b/lib/Target/ARM/Thumb2InstrInfo.h
@@ -26,8 +26,8 @@ class Thumb2InstrInfo : public ARMBaseInstrInfo {
 public:
   explicit Thumb2InstrInfo(const ARMSubtarget &STI);
 
-  /// Return the noop instruction to use for a noop.
-  void getNoop(MCInst &NopInst) const override;
+  /// getNoopForMachoTarget - Return the noop instruction to use for a noop.
+  void getNoopForMachoTarget(MCInst &NopInst) const override;
 
   // Return the non-pre/post incrementing version of 'Opc'. Return 0
   // if there is not such an opcode.

diff --git a/lib/Target/PowerPC/PPCInstrInfo.cpp b/lib/Target/PowerPC/PPCInstrInfo.cpp
index 790a890..8e159f4 100644 (file)
--- a/lib/Target/PowerPC/PPCInstrInfo.cpp
+++ b/lib/Target/PowerPC/PPCInstrInfo.cpp
@@ -440,8 +440,8 @@ void PPCInstrInfo::insertNoop(MachineBasicBlock &MBB,
   BuildMI(MBB, MI, DL, get(Opcode));
 }
 
-/// Return the noop instruction to use for a noop.
-void PPCInstrInfo::getNoop(MCInst &NopInst) const {
+/// getNoopForMachoTarget - Return the noop instruction to use for a noop.
+void PPCInstrInfo::getNoopForMachoTarget(MCInst &NopInst) const {
   NopInst.setOpcode(PPC::NOP);
 }
 

diff --git a/lib/Target/PowerPC/PPCInstrInfo.h b/lib/Target/PowerPC/PPCInstrInfo.h
index b30d09e..f11aed8 100644 (file)
--- a/lib/Target/PowerPC/PPCInstrInfo.h
+++ b/lib/Target/PowerPC/PPCInstrInfo.h
@@ -269,7 +269,7 @@ public:
   ///
   unsigned getInstSizeInBytes(const MachineInstr &MI) const override;
 
-  void getNoop(MCInst &NopInst) const override;
+  void getNoopForMachoTarget(MCInst &NopInst) const override;
 
   std::pair<unsigned, unsigned>
   decomposeMachineOperandsTargetFlags(unsigned TF) const override;

diff --git a/lib/Target/X86/X86InstrInfo.cpp b/lib/Target/X86/X86InstrInfo.cpp
index 7e69e94..7b456fd 100644 (file)
--- a/lib/Target/X86/X86InstrInfo.cpp
+++ b/lib/Target/X86/X86InstrInfo.cpp
@@ -9514,7 +9514,7 @@ void X86InstrInfo::setExecutionDomain(MachineInstr &MI, unsigned Domain) const {
 }
 
 /// Return the noop instruction to use for a noop.
-void X86InstrInfo::getNoop(MCInst &NopInst) const {
+void X86InstrInfo::getNoopForMachoTarget(MCInst &NopInst) const {
   NopInst.setOpcode(X86::NOOP);
 }
 

diff --git a/lib/Target/X86/X86InstrInfo.h b/lib/Target/X86/X86InstrInfo.h
index 3856783..2fee485 100644 (file)
--- a/lib/Target/X86/X86InstrInfo.h
+++ b/lib/Target/X86/X86InstrInfo.h
@@ -457,7 +457,7 @@ public:
                                int64_t Offset1, int64_t Offset2,
                                unsigned NumLoads) const override;
 
-  void getNoop(MCInst &NopInst) const override;
+  void getNoopForMachoTarget(MCInst &NopInst) const override;
 
   bool
   reverseBranchCondition(SmallVectorImpl<MachineOperand> &Cond) const override;

diff --git a/test/CodeGen/X86/empty-function.ll b/test/CodeGen/X86/empty-function.ll
deleted file mode 100644 (file)
index 92bebd0..0000000
--- a/test/CodeGen/X86/empty-function.ll
+++ /dev/null
@@ -1,22 +0,0 @@
-; RUN: llc < %s -mtriple=i686-pc-win32   | FileCheck -check-prefix=CHECK -check-prefix=WIN32 %s
-; RUN: llc < %s -mtriple=x86_64-pc-win32 | FileCheck -check-prefix=CHECK -check-prefix=WIN64 %s
-; RUN: llc < %s -mtriple=i386-linux-gnu  | FileCheck -check-prefix=LINUX %s
-
-target datalayout = "e-m:x-p:32:32-i64:64-f80:32-n8:16:32-a:0:32-S32"
-target triple = "i686-pc-windows-msvc18.0.0"
-
-; Don't emit empty functions on Windows; it can lead to duplicate entries
-; (multiple functions sharing the same RVA) in the Guard CF Function Table which
-; the kernel refuses to load.
-
-define void @f() {
-entry:
-  unreachable
-
-; CHECK-LABEL: f:
-; WIN32: nop
-; WIN64: ud2
-; LINUX-NOT: nop
-; LINUX-NOT: ud2
-
-}