[PATCH] D45520: [PowerPC] add secure plt support for TLS symbols

[Strahinja Petrovic via Phabricator via llvm-commits]

spetrovic created this revision.
spetrovic added reviewers: jhibbits, joerg, nemanjai.
Herald added subscribers: llvm-commits, kbarton.

This patch supports secure plt mode for TLS symbols, it's extension for https://reviews.llvm.org/D42112.


Repository:
  rL LLVM

https://reviews.llvm.org/D45520

Files:
  lib/Target/PowerPC/InstPrinter/PPCInstPrinter.cpp
  lib/Target/PowerPC/PPCAsmPrinter.cpp
  lib/Target/PowerPC/PPCISelDAGToDAG.cpp
  test/CodeGen/PowerPC/ppc32-secure-plt-tls.ll


Index: test/CodeGen/PowerPC/ppc32-secure-plt-tls.ll
===================================================================
--- test/CodeGen/PowerPC/ppc32-secure-plt-tls.ll
+++ test/CodeGen/PowerPC/ppc32-secure-plt-tls.ll
@@ -0,0 +1,17 @@
+; RUN: llc < %s -mtriple=powerpc-unknown-linux-gnu -mattr=+secure-plt -relocation-model=pic | FileCheck -check-prefix=SECURE-PLT-TLS %s
+
+ at a = thread_local local_unnamed_addr global i32 6, align 4
+define i32 @main() local_unnamed_addr #0 {
+entry:
+  %0 = load i32, i32* @a, align 4
+  ret i32 %0
+}
+
+
+!llvm.module.flags = !{!0}
+!0 = !{i32 7, !"PIC Level", i32 2}
+
+; SECURE-PLT-TLS:       mflr 30
+; SECURE-PLT-TLS-NEXT:  addis 30, 30, .LTOC-.L0$pb at ha
+; SECURE-PLT-TLS-NEXT:  addi 30, 30, .LTOC-.L0$pb at l
+; SECURE-PLT-TLS:       bl __tls_get_addr(a at tlsgd)@PLT+32768
\ No newline at end of file
Index: lib/Target/PowerPC/PPCISelDAGToDAG.cpp
===================================================================
--- lib/Target/PowerPC/PPCISelDAGToDAG.cpp
+++ lib/Target/PowerPC/PPCISelDAGToDAG.cpp
@@ -4008,7 +4008,17 @@
     if (trySETCC(N))
       return;
     break;
+  case PPCISD::ADDI_TLSLD_L_ADDR:
+  case PPCISD::ADDI_TLSGD_L_ADDR: {
+    const Module *Mod = MF->getFunction().getParent();
+    if (PPCLowering->getPointerTy(CurDAG->getDataLayout()) != MVT::i32 ||
+        !PPCSubTarget->isSecurePlt() || !PPCSubTarget->isTargetELF() ||
+        Mod->getPICLevel() == PICLevel::SmallPIC)
+      break;
 
+      getGlobalBaseReg();
+  }
+    break;
   case PPCISD::CALL: {
     const Module *M = MF->getFunction().getParent();
 
Index: lib/Target/PowerPC/PPCAsmPrinter.cpp
===================================================================
--- lib/Target/PowerPC/PPCAsmPrinter.cpp
+++ lib/Target/PowerPC/PPCAsmPrinter.cpp
@@ -487,8 +487,12 @@
   if (!Subtarget->isPPC64() && !Subtarget->isDarwin() &&
       isPositionIndependent())
     Kind = MCSymbolRefExpr::VK_PLT;
-  const MCSymbolRefExpr *TlsRef =
+  const MCExpr *TlsRef =
     MCSymbolRefExpr::create(TlsGetAddr, Kind, OutContext);
+    if (Kind == MCSymbolRefExpr::VK_PLT && Subtarget->isSecurePlt())
+      TlsRef = MCBinaryExpr::createAdd(TlsRef,
+                                       MCConstantExpr::create(32768, OutContext),
+                                       OutContext);
   const MachineOperand &MO = MI->getOperand(2);
   const GlobalValue *GValue = MO.getGlobal();
   MCSymbol *MOSymbol = getSymbol(GValue);
Index: lib/Target/PowerPC/InstPrinter/PPCInstPrinter.cpp
===================================================================
--- lib/Target/PowerPC/InstPrinter/PPCInstPrinter.cpp
+++ lib/Target/PowerPC/InstPrinter/PPCInstPrinter.cpp
@@ -442,13 +442,22 @@
   // On PPC64, VariantKind is VK_None, but on PPC32, it's VK_PLT, and it must
   // come at the _end_ of the expression.
   const MCOperand &Op = MI->getOperand(OpNo);
-  const MCSymbolRefExpr &refExp = cast<MCSymbolRefExpr>(*Op.getExpr());
-  O << refExp.getSymbol().getName();
+  const MCSymbolRefExpr *refExp = nullptr;
+  const MCConstantExpr *constExp = nullptr;
+  if (const MCBinaryExpr *BinExpr = dyn_cast<MCBinaryExpr>(Op.getExpr())) {
+    refExp = cast<MCSymbolRefExpr>(BinExpr->getLHS());
+    constExp = cast<MCConstantExpr>(BinExpr->getRHS());
+  } else
+    refExp = cast<MCSymbolRefExpr>(Op.getExpr());
+
+  O << refExp->getSymbol().getName();
   O << '(';
   printOperand(MI, OpNo+1, O);
   O << ')';
-  if (refExp.getKind() != MCSymbolRefExpr::VK_None)
-    O << '@' << MCSymbolRefExpr::getVariantKindName(refExp.getKind());
+  if (refExp->getKind() != MCSymbolRefExpr::VK_None)
+    O << '@' << MCSymbolRefExpr::getVariantKindName(refExp->getKind());
+  if (constExp != nullptr)
+    O << '+' << constExp->getValue();
 }
 
 /// showRegistersWithPercentPrefix - Check if this register name should be


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