Enable optimization suggested by Chris Lattner to not emit reloc stubs for

static global variables whose addresses are taken.  This allows us to
convert the following code for taking the address of a static function foo

        addis r2, r30, ha16(Ll1__2E_foo_2$non_lazy_ptr-"L00001$pb")
        lwz r3, lo16(Ll1__2E_foo_2$non_lazy_ptr-"L00001$pb")(r2)

which also includes linker stub code emitted at the end of the .s file not
shown here, and replace it with this:

        addis r2, r30, ha16(l1__2E_foo_2-"L00001$pb")
        la r3, lo16(l1__2E_foo_2-"L00001$pb")(r2)

which in addition to not needing linker help, also has no load instruction.
For those not up on PowerPC mnemonics, la is shorthand for add immediate.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@18239 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/PowerPC/PPC32ISelSimple.cpp b/lib/Target/PowerPC/PPC32ISelSimple.cpp
index 465f560266a4816914c2b92e9135c01792125824..f2fc56395748b6d0a612f3cdc7d478db757dfd11 100644 (file)
--- a/lib/Target/PowerPC/PPC32ISelSimple.cpp
+++ b/lib/Target/PowerPC/PPC32ISelSimple.cpp
@@ -703,7 +703,7 @@ void PPC32ISel::copyConstantToRegister(MachineBasicBlock *MBB,
     BuildMI(*MBB, IP, PPC::LOADHiAddr, 2, TmpReg)
       .addReg(getGlobalBaseReg(MBB, IP)).addGlobalAddress(GV);
 
-    if (GV->hasWeakLinkage() || GV->isExternal() || isa<Function>(GV)) {
+    if (GV->hasWeakLinkage() || GV->isExternal()) {
       BuildMI(*MBB, IP, PPC::LWZ, 2, R).addGlobalAddress(GV).addReg(TmpReg);
     } else {
       BuildMI(*MBB, IP, PPC::LA, 2, R).addReg(TmpReg).addGlobalAddress(GV);

diff --git a/lib/Target/PowerPC/PPCAsmPrinter.cpp b/lib/Target/PowerPC/PPCAsmPrinter.cpp
index 4316abc61359c77276e5025ff6f8319a0b947e52..f4e36bab2e8c458be93b90cdf17e7640197d24c0 100644 (file)
--- a/lib/Target/PowerPC/PPCAsmPrinter.cpp
+++ b/lib/Target/PowerPC/PPCAsmPrinter.cpp
@@ -33,6 +33,7 @@
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Target/MRegisterInfo.h"
+#include "llvm/Target/TargetInstrInfo.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/ADT/StringExtras.h"
 #include <set>
@@ -67,7 +68,7 @@ namespace {
     bool printInstruction(const MachineInstr *MI);
 
     void printMachineInstruction(const MachineInstr *MI);
-    void printOp(const MachineOperand &MO, bool LoadAddrOp = false);
+    void printOp(const MachineOperand &MO, bool IsCallOp = false);
 
     void printOperand(const MachineInstr *MI, unsigned OpNo, MVT::ValueType VT){
       const MachineOperand &MO = MI->getOperand(OpNo);
@@ -108,7 +109,8 @@ namespace {
       if (MI->getOperand(OpNo).isImmediate()) {
         O << "$+" << MI->getOperand(OpNo).getImmedValue() << '\n';
       } else {
-        printOp(MI->getOperand(OpNo));
+        printOp(MI->getOperand(OpNo), 
+                TM.getInstrInfo()->isCall(MI->getOpcode()));
       }
     }
     void printPICLabel(const MachineInstr *MI, unsigned OpNo,
@@ -120,7 +122,7 @@ namespace {
     void printSymbolHi(const MachineInstr *MI, unsigned OpNo,
                        MVT::ValueType VT) {
       O << "ha16(";
-      printOp(MI->getOperand(OpNo), true /* LoadAddrOp */);
+      printOp(MI->getOperand(OpNo));
       O << "-\"L0000" << LabelNumber << "$pb\")";
     }
     void printSymbolLo(const MachineInstr *MI, unsigned OpNo,
@@ -132,7 +134,7 @@ namespace {
         O << (short)MI->getOperand(OpNo).getImmedValue();
       } else {
         O << "lo16(";
-        printOp(MI->getOperand(OpNo), true /* LoadAddrOp */);
+        printOp(MI->getOperand(OpNo));
         O << "-\"L0000" << LabelNumber << "$pb\")";
       }
     }
@@ -307,8 +309,7 @@ FunctionPass *llvm::createAIXAsmPrinter(std::ostream &o, TargetMachine &tm) {
 // Include the auto-generated portion of the assembly writer
 #include "PowerPCGenAsmWriter.inc"
 
-void PowerPCAsmPrinter::printOp(const MachineOperand &MO,
-                              bool LoadAddrOp /* = false */) {
+void PowerPCAsmPrinter::printOp(const MachineOperand &MO, bool IsCallOp) {
   const MRegisterInfo &RI = *TM.getRegisterInfo();
   int new_symbol;
   
@@ -359,27 +360,23 @@ void PowerPCAsmPrinter::printOp(const MachineOperand &MO,
     // wary however not to output $stub for external functions whose addresses
     // are taken.  Those should be emitted as $non_lazy_ptr below.
     Function *F = dyn_cast<Function>(GV);
-    if (F && F->isExternal() && !LoadAddrOp &&
-        getTM().CalledFunctions.count(F)) {
+    if (F && F->isExternal() && IsCallOp && getTM().CalledFunctions.count(F)) {
       FnStubs.insert(Name);
       O << "L" << Name << "$stub";
       return;
     }
     
     // External or weakly linked global variables need non-lazily-resolved stubs
-    if ((GV->isExternal() || GV->hasWeakLinkage() || GV->hasLinkOnceLinkage()) 
+    if ((GV->isExternal() || GV->hasWeakLinkage() || GV->hasLinkOnceLinkage())
          && getTM().AddressTaken.count(GV)) {
-      GVStubs.insert(Name);
+      if (GV->hasLinkOnceLinkage())
+        LinkOnceStubs.insert(Name);
+      else
+        GVStubs.insert(Name);
       O << "L" << Name << "$non_lazy_ptr";
       return;
     }
-    
-    if (F && LoadAddrOp && getTM().AddressTaken.count(GV)) {
-      LinkOnceStubs.insert(Name);
-      O << "L" << Name << "$non_lazy_ptr";
-      return;
-    }
-            
+
     O << Mang->getValueName(GV);
     return;
   }

diff --git a/lib/Target/PowerPC/PPCCodeEmitter.cpp b/lib/Target/PowerPC/PPCCodeEmitter.cpp
index e46d0ea4c361874c81650674d31bd7f3b78aaa36..2f9c8c23b3e9d335f8458c15c00d58fdd9fca0ba 100644 (file)
--- a/lib/Target/PowerPC/PPCCodeEmitter.cpp
+++ b/lib/Target/PowerPC/PPCCodeEmitter.cpp
@@ -199,20 +199,20 @@ int PPC32CodeEmitter::getMachineOpValue(MachineInstr &MI, MachineOperand &MO) {
       Offset = -((intptr_t)MovePCtoLROffset+4);
 
       if (MI.getOpcode() == PPC::LOADHiAddr) {
-        if (GV->hasWeakLinkage() || GV->isExternal() || isa<Function>(GV))
+        if (GV->hasWeakLinkage() || GV->isExternal())
           Reloc = PPC::reloc_absolute_ptr_high;   // Pointer to stub
         else
           Reloc = PPC::reloc_absolute_high;       // Pointer to symbol
 
       } else if (MI.getOpcode() == PPC::LA) {
-        assert(!(GV->hasWeakLinkage() || GV->isExternal() || isa<Function>(GV))
+        assert(!(GV->hasWeakLinkage() || GV->isExternal())
                && "Something in the ISEL changed\n");
 
         Reloc = PPC::reloc_absolute_low;
       } else if (MI.getOpcode() == PPC::LWZ) {
         Reloc = PPC::reloc_absolute_ptr_low;
 
-        assert((GV->hasWeakLinkage() || GV->isExternal() || isa<Function>(GV))&&
+        assert((GV->hasWeakLinkage() || GV->isExternal()) &&
                "Something in the ISEL changed\n");
       } else {
         // These don't show up for global value references AFAIK, only for