Darwin ABI issues: weak, linkonce, etc. dynamic-no-pic support is complete.

Also fixed a function stub bug. Added weak and linkonce support for
x86 Linux.

llvm-svn: 26038

lib/Target/X86/X86ATTAsmPrinter.cpp

@@ -33,12 +33,32 @@ bool X86ATTAsmPrinter::runOnMachineFunction(MachineFunction &MF) {
   EmitConstantPool(MF.getConstantPool());
 
   // Print out labels for the function.
-  SwitchSection("\t.text\n", MF.getFunction());
-  EmitAlignment(4);     // FIXME: This should be parameterized somewhere.
-  if (!MF.getFunction()->hasInternalLinkage())
+  const Function *F = MF.getFunction();
+  switch (F->getLinkage()) {
+  default: assert(0 && "Unknown linkage type!");
+  case Function::InternalLinkage:  // Symbols default to internal.
+    SwitchSection(".text", F);
+    EmitAlignment(4, F);     // FIXME: This should be parameterized somewhere.
+    break;
+  case Function::ExternalLinkage:
+    SwitchSection(".text", F);
+    EmitAlignment(4, F);     // FIXME: This should be parameterized somewhere.
     O << "\t.globl\t" << CurrentFnName << "\n";
-  if (HasDotTypeDotSizeDirective)
-    O << "\t.type\t" << CurrentFnName << ", @function\n";
+    break;
+  case Function::WeakLinkage:
+  case Function::LinkOnceLinkage:
+    if (forDarwin) {
+      SwitchSection(".section __TEXT,__textcoal_nt,coalesced,pure_instructions",
+                    F);
+      O << "\t.weak_definition\t" << CurrentFnName << "\n";
+    } else {
+      EmitAlignment(4, F);     // FIXME: This should be parameterized somewhere.
+      O << "\t.section\t.llvm.linkonce.t." << CurrentFnName
+        << ",\"ax\",@progbits\n";
+      O << "\t.weak " << CurrentFnName << "\n";
+    }
+    break;
+  }
   O << CurrentFnName << ":\n";
 
   // Print out code for the function.
@@ -95,27 +115,24 @@ void X86ATTAsmPrinter::printOperand(const MachineInstr *MI, unsigned OpNo,
     return;
   case MachineOperand::MO_GlobalAddress: {
     bool isCallOp = Modifier && !strcmp(Modifier, "call");
-    // Darwin block shameless ripped from PowerPCAsmPrinter.cpp
+    bool isMemOp  = Modifier && !strcmp(Modifier, "mem");
+    // Darwin block shameless ripped from PPCAsmPrinter.cpp
     if (forDarwin) {
-      if (!isCallOp) O << '$';
+      if (!isMemOp && !isCallOp) O << '$';
       GlobalValue *GV = MO.getGlobal();
       std::string Name = Mang->getValueName(GV);
-
-      // Dynamically-resolved functions need a stub for the function.  Be
-      // wary however not to output $stub for external functions whose addresses
-      // are taken.  Those should be emitted as $non_lazy_ptr below.
-      Function *F = dyn_cast<Function>(GV);
-      if (F && isCallOp && F->isExternal()) {
-        FnStubs.insert(Name);
-        O << "L" << Name << "$stub";
-      } else if (GV->hasLinkOnceLinkage()) {
       // Link-once, External, or Weakly-linked global variables need
       // non-lazily-resolved stubs
-        LinkOnceStubs.insert(Name);
-        O << "L" << Name << "$non_lazy_ptr";
-      } else if (GV->isExternal() || GV->hasWeakLinkage()) {
+      if (GV->isExternal() || GV->hasWeakLinkage() ||
+          GV->hasLinkOnceLinkage()) {
+        // Dynamically-resolved functions need a stub for the function.
+        if (isCallOp && isa<Function>(GV) && cast<Function>(GV)->isExternal()) {
+          FnStubs.insert(Name);
+          O << "L" << Name << "$stub";
+        } else {
           GVStubs.insert(Name);
           O << "L" << Name << "$non_lazy_ptr";
+        }
       } else {
         O << Mang->getValueName(GV);
       }
@@ -126,7 +143,7 @@ void X86ATTAsmPrinter::printOperand(const MachineInstr *MI, unsigned OpNo,
         O << Offset;
       return;
     }
-    if (!isCallOp) O << '$';
+    if (!isMemOp && !isCallOp) O << '$';
     O << Mang->getValueName(MO.getGlobal());
     int Offset = MO.getOffset();
     if (Offset > 0)
@@ -137,13 +154,14 @@ void X86ATTAsmPrinter::printOperand(const MachineInstr *MI, unsigned OpNo,
   }
   case MachineOperand::MO_ExternalSymbol: {
     bool isCallOp = Modifier && !strcmp(Modifier, "call");
+    bool isMemOp  = Modifier && !strcmp(Modifier, "mem");
     if (isCallOp && forDarwin) {
       std::string Name(GlobalPrefix); Name += MO.getSymbolName();
       FnStubs.insert(Name);
       O << "L" << Name << "$stub";
       return;
     }
-    if (!isCallOp) O << '$';
+    if (!isMemOp && !isCallOp) O << '$';
     O << GlobalPrefix << MO.getSymbolName();
     return;
   }
@@ -197,7 +215,7 @@ void X86ATTAsmPrinter::printMemReference(const MachineInstr *MI, unsigned Op){
   }
 
   if (DispSpec.isGlobalAddress()) {
-    printOperand(MI, Op+3, "call");
+    printOperand(MI, Op+3, "mem");
   } else {
     int DispVal = DispSpec.getImmedValue();
     if (DispVal || (!IndexReg.getReg() && !BaseReg.getReg()))

lib/Target/X86/X86AsmPrinter.cpp

@@ -80,113 +80,93 @@ bool X86SharedAsmPrinter::doFinalization(Module &M) {
   const TargetData &TD = TM.getTargetData();
 
   // Print out module-level global variables here.
-  for (Module::const_global_iterator I = M.global_begin(),
-       E = M.global_end(); I != E; ++I) {
+  for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
+       I != E; ++I) {
     if (!I->hasInitializer()) continue;   // External global require no code
     
     // Check to see if this is a special global used by LLVM, if so, emit it.
     if (I->hasAppendingLinkage() && EmitSpecialLLVMGlobal(I))
       continue;
     
-    O << "\n\n";
     std::string name = Mang->getValueName(I);
     Constant *C = I->getInitializer();
     unsigned Size = TD.getTypeSize(C->getType());
     unsigned Align = getPreferredAlignmentLog(I);
 
-    switch (I->getLinkage()) {
-    default: assert(0 && "Unknown linkage type!");
-    case GlobalValue::LinkOnceLinkage:
-    case GlobalValue::WeakLinkage:   // FIXME: Verify correct for weak.
-      if (C->isNullValue()) {
-        O << COMMDirective << name << "," << Size;
-        if (COMMDirectiveTakesAlignment)
-          O << "," << (1 << Align);
-        O << "\t\t" << CommentString << " " << I->getName() << "\n";
-        continue;
-      }
-      
-      // Nonnull linkonce -> weak
-      O << "\t.weak " << name << "\n";
-      O << "\t.section\t.llvm.linkonce.d." << name << ",\"aw\",@progbits\n";
-      SwitchSection("", I);
-      break;
-    case GlobalValue::InternalLinkage:
-      if (C->isNullValue()) {
-        if (LCOMMDirective) {
-          O << LCOMMDirective << name << "," << Size << "," << Align;
-          continue;
-        } else {
-          SwitchSection(".bss", I);
-          O << "\t.local " << name << "\n";
-          O << COMMDirective << name << "," << Size;
-          if (COMMDirectiveTakesAlignment)
-            O << "," << (1 << Align);
-          O << "\t\t# ";
-          WriteAsOperand(O, I, true, true, &M);
-          O << "\n";
-          continue;
-        }
-      }
+    if (C->isNullValue() && /* FIXME: Verify correct */
+        (I->hasInternalLinkage() || I->hasWeakLinkage() ||
+         I->hasLinkOnceLinkage())) {
+      if (Size == 0) Size = 1;   // .comm Foo, 0 is undefined, avoid it.
+      if (forDarwin) {
         SwitchSection(".data", I);
+        if (I->hasInternalLinkage())
+          O << LCOMMDirective << name << "," << Size << "," << Align;
+        else
+          O << COMMDirective  << name << "," << Size;
+      } else {
+        SwitchSection(".local", I);
+        O << COMMDirective  << name << "," << Size << "," << Align;
+      }
+      O << "\t\t" << CommentString << " '" << I->getName() << "'\n";
+    } else {
+      switch (I->getLinkage()) {
+      case GlobalValue::LinkOnceLinkage:
+      case GlobalValue::WeakLinkage:
+        if (forDarwin) {
+          O << "\t.globl " << name << '\n'
+            << "\t.weak_definition " << name << '\n';
+          SwitchSection(".section __DATA,__datacoal_nt,coalesced", I);
+        } else {
+          O << "\t.section\t.llvm.linkonce.d." << name << ",\"aw\",@progbits\n";
+          O << "\t.weak " << name << "\n";
+        }
         break;
       case GlobalValue::AppendingLinkage:
         // FIXME: appending linkage variables should go into a section of
         // their name or something.  For now, just emit them as external.
       case GlobalValue::ExternalLinkage:
-      SwitchSection(C->isNullValue() ? ".bss" : ".data", I);
         // If external or appending, declare as a global symbol
         O << "\t.globl " << name << "\n";
+        // FALL THROUGH
+      case GlobalValue::InternalLinkage:
+        SwitchSection(".data", I);
         break;
+      default:
+        assert(0 && "Unknown linkage type!");
       }
 
-    EmitAlignment(Align);
-    if (HasDotTypeDotSizeDirective) {
-      O << "\t.type " << name << ",@object\n";
-      O << "\t.size " << name << "," << Size << "\n";
-    }
-    O << name << ":\t\t\t" << CommentString << ' ' << I->getName() << '\n';
+      EmitAlignment(Align, I);
+      O << name << ":\t\t\t\t" << CommentString << " '" << I->getName()
+        << "'\n";
       EmitGlobalConstant(C);
+      O << '\n';
+    }
   }
   
   if (forDarwin) {
     SwitchSection("", 0);
-    // Output stubs for external global variables
-    if (GVStubs.begin() != GVStubs.end())
-      O << "\t.non_lazy_symbol_pointer\n";
-    for (std::set<std::string>::iterator i = GVStubs.begin(), e = GVStubs.end();
-         i != e; ++i) {
-      O << "L" << *i << "$non_lazy_ptr:\n";
-      O << "\t.indirect_symbol " << *i << "\n";
-      O << "\t.long\t0\n";
-    }
 
     // Output stubs for dynamically-linked functions
     unsigned j = 1;
     for (std::set<std::string>::iterator i = FnStubs.begin(), e = FnStubs.end();
          i != e; ++i, ++j) {
-      O << "\t.symbol_stub\n";
+      SwitchSection(".section __IMPORT,__jump_table,symbol_stubs,"
+                    "self_modifying_code+pure_instructions,5", 0);
       O << "L" << *i << "$stub:\n";
       O << "\t.indirect_symbol " << *i << "\n";
-      O << "\tjmp\t*L" << j << "$lz\n";
-      O << "L" << *i << "$stub_binder:\n";
-      O << "\tpushl\t$L" << j << "$lz\n";
-      O << "\tjmp\tdyld_stub_binding_helper\n";
-      O << "\t.section __DATA, __la_sym_ptr3,lazy_symbol_pointers\n";
-      O << "L" << j << "$lz:\n";
-      O << "\t.indirect_symbol " << *i << "\n";
-      O << "\t.long\tL" << *i << "$stub_binder\n";
+      O << "\thlt ; hlt ; hlt ; hlt ; hlt\n";
     }
 
     O << "\n";
 
-    // Output stubs for link-once variables
-    if (LinkOnceStubs.begin() != LinkOnceStubs.end())
-      O << ".data\n.align 2\n";
-    for (std::set<std::string>::iterator i = LinkOnceStubs.begin(),
-         e = LinkOnceStubs.end(); i != e; ++i) {
-      O << "L" << *i << "$non_lazy_ptr:\n"
-        << "\t.long\t" << *i << '\n';
+    // Output stubs for external and common global variables.
+    if (GVStubs.begin() != GVStubs.end())
+      SwitchSection(".section __IMPORT,__pointers,non_lazy_symbol_pointers", 0);
+    for (std::set<std::string>::iterator i = GVStubs.begin(), e = GVStubs.end();
+         i != e; ++i) {
+      O << "L" << *i << "$non_lazy_ptr:\n";
+      O << "\t.indirect_symbol " << *i << "\n";
+      O << "\t.long\t0\n";
     }
   }
 

lib/Target/X86/X86ISelLowering.cpp

@@ -1876,11 +1876,13 @@ SDOperand X86TargetLowering::LowerOperation(SDOperand Op, SelectionDAG &DAG) {
     // the GlobalAddress must be in the base or index register of the address,
     // not the GV offset field.
     if (getTargetMachine().
-        getSubtarget<X86Subtarget>().getIndirectExternAndWeakGlobals() &&
-        (GV->hasWeakLinkage() || GV->isExternal()))
+        getSubtarget<X86Subtarget>().getIndirectExternAndWeakGlobals()) {
+      if (GV->hasWeakLinkage() || GV->hasLinkOnceLinkage() ||
+          (GV->isExternal() && !GV->hasNotBeenReadFromBytecode()))
         Result = DAG.getLoad(MVT::i32, DAG.getEntryNode(),
                              DAG.getTargetGlobalAddress(GV, getPointerTy()),
                              DAG.getSrcValue(NULL));
+    }
     return Result;
   }
   case ISD::VASTART: {

lib/Target/X86/X86IntelAsmPrinter.cpp

@@ -109,7 +109,7 @@ void X86IntelAsmPrinter::printOp(const MachineOperand &MO,
     abort ();
     return;
   case MachineOperand::MO_GlobalAddress: {
-    if (!Modifier || strcmp(Modifier, "call"))
+    if (!Modifier || strcmp(Modifier, "call") || strcmp(Modifier, "mem"))
       O << "OFFSET ";
     O << Mang->getValueName(MO.getGlobal());
     int Offset = MO.getOffset();
@@ -161,7 +161,7 @@ void X86IntelAsmPrinter::printMemReference(const MachineInstr *MI, unsigned Op){
   O << "[";
   bool NeedPlus = false;
   if (BaseReg.getReg()) {
-    printOp(BaseReg, "call");
+    printOp(BaseReg, "mem");
     NeedPlus = true;
   }
 
@@ -176,7 +176,7 @@ void X86IntelAsmPrinter::printMemReference(const MachineInstr *MI, unsigned Op){
   if (DispSpec.isGlobalAddress()) {
     if (NeedPlus)
       O << " + ";
-    printOp(DispSpec, "call");
+    printOp(DispSpec, "mem");
   } else {
     int DispVal = DispSpec.getImmedValue();
     if (DispVal || (!BaseReg.getReg() && !IndexReg.getReg())) {