[PowerPC][ISelLowering] Support -mstack-protector-guard=tls

Add support for using a thread-local variable with a specified offset
for holding the stack guard canary value.

Signed-off-by: Keith Packard <[email protected]>

Author: keith-packard

clang/lib/Driver/ToolChains/Clang.cpp

@@ -3605,7 +3605,7 @@ static void RenderSSPOptions(const Driver &D, const ToolChain &TC,
     StringRef Value = A->getValue();
     if (!EffectiveTriple.isX86() && !EffectiveTriple.isAArch64() &&
         !EffectiveTriple.isARM() && !EffectiveTriple.isThumb() &&
-        !EffectiveTriple.isRISCV())
+        !EffectiveTriple.isRISCV() && !EffectiveTriple.isPPC())
       D.Diag(diag::err_drv_unsupported_opt_for_target)
           << A->getAsString(Args) << TripleStr;
     if ((EffectiveTriple.isX86() || EffectiveTriple.isARM() ||
@@ -3645,7 +3645,7 @@ static void RenderSSPOptions(const Driver &D, const ToolChain &TC,
           << A->getOption().getName() << Value << "sysreg global";
       return;
     }
-    if (EffectiveTriple.isRISCV()) {
+    if (EffectiveTriple.isRISCV() || EffectiveTriple.isPPC()) {
       if (Value != "tls" && Value != "global") {
         D.Diag(diag::err_drv_invalid_value_with_suggestion)
             << A->getOption().getName() << Value << "tls global";
@@ -3666,7 +3666,7 @@ static void RenderSSPOptions(const Driver &D, const ToolChain &TC,
     StringRef Value = A->getValue();
     if (!EffectiveTriple.isX86() && !EffectiveTriple.isAArch64() &&
         !EffectiveTriple.isARM() && !EffectiveTriple.isThumb() &&
-        !EffectiveTriple.isRISCV())
+        !EffectiveTriple.isRISCV() && !EffectiveTriple.isPPC())
       D.Diag(diag::err_drv_unsupported_opt_for_target)
           << A->getAsString(Args) << TripleStr;
     int Offset;
@@ -3686,7 +3686,7 @@ static void RenderSSPOptions(const Driver &D, const ToolChain &TC,
   if (Arg *A = Args.getLastArg(options::OPT_mstack_protector_guard_reg_EQ)) {
     StringRef Value = A->getValue();
     if (!EffectiveTriple.isX86() && !EffectiveTriple.isAArch64() &&
-        !EffectiveTriple.isRISCV())
+        !EffectiveTriple.isRISCV() && !EffectiveTriple.isPPC())
       D.Diag(diag::err_drv_unsupported_opt_for_target)
           << A->getAsString(Args) << TripleStr;
     if (EffectiveTriple.isX86() && (Value != "fs" && Value != "gs")) {
@@ -3703,6 +3703,16 @@ static void RenderSSPOptions(const Driver &D, const ToolChain &TC,
           << A->getOption().getName() << Value << "tp";
       return;
     }
+    if (EffectiveTriple.isPPC64() && Value != "r13") {
+      D.Diag(diag::err_drv_invalid_value_with_suggestion)
+          << A->getOption().getName() << Value << "r13";
+      return;
+    }
+    if (EffectiveTriple.isPPC32() && Value != "r2") {
+      D.Diag(diag::err_drv_invalid_value_with_suggestion)
+          << A->getOption().getName() << Value << "r2";
+      return;
+    }
     A->render(Args, CmdArgs);
   }
 

llvm/lib/Target/PowerPC/PPCISelLowering.cpp

@@ -17889,10 +17889,10 @@ SDValue PPCTargetLowering::getNegatedExpression(SDValue Op, SelectionDAG &DAG,
 }
 
 // Override to enable LOAD_STACK_GUARD lowering on Linux.
-bool PPCTargetLowering::useLoadStackGuardNode() const {
-  if (!Subtarget.isTargetLinux())
-    return TargetLowering::useLoadStackGuardNode();
-  return true;
+bool PPCTargetLowering::useLoadStackGuardNode(const Module &M) const {
+  if (M.getStackProtectorGuard() == "tls" || Subtarget.isTargetLinux())
+    return true;
+  return TargetLowering::useLoadStackGuardNode();
 }
 
 // Override to disable global variable loading on Linux and insert AIX canary

llvm/lib/Target/PowerPC/PPCISelLowering.h

@@ -1137,7 +1137,7 @@ namespace llvm {
     getExceptionSelectorRegister(const Constant *PersonalityFn) const override;
 
     /// Override to support customized stack guard loading.
-    bool useLoadStackGuardNode() const override;
+    bool useLoadStackGuardNode(const Module &M) const override;
     void insertSSPDeclarations(Module &M) const override;
     Value *getSDagStackGuard(const Module &M) const override;
 

llvm/lib/Target/PowerPC/PPCInstrInfo.cpp

@@ -35,6 +35,7 @@
 #include "llvm/CodeGen/ScheduleDAG.h"
 #include "llvm/CodeGen/SlotIndexes.h"
 #include "llvm/CodeGen/StackMaps.h"
+#include "llvm/IR/Module.h"
 #include "llvm/MC/MCAsmInfo.h"
 #include "llvm/MC/MCInst.h"
 #include "llvm/MC/TargetRegistry.h"
@@ -3107,9 +3108,17 @@ bool PPCInstrInfo::expandPostRAPseudo(MachineInstr &MI) const {
     return true;
   }
   case TargetOpcode::LOAD_STACK_GUARD: {
-    assert(Subtarget.isTargetLinux() &&
-           "Only Linux target is expected to contain LOAD_STACK_GUARD");
-    const int64_t Offset = Subtarget.isPPC64() ? -0x7010 : -0x7008;
+    // MBB might not have an associated BB; use the function to find one
+    auto M = MBB.getParent()->getFunction().getEntryBlock().getModule();
+    assert(
+        (Subtarget.isTargetLinux() || M->getStackProtectorGuard() == "tls") &&
+        "Only Linux target or tls mode are expected to contain "
+        "LOAD_STACK_GUARD");
+    int64_t Offset;
+    if (M->getStackProtectorGuard() == "tls")
+      Offset = M->getStackProtectorGuardOffset();
+    else
+      Offset = Subtarget.isPPC64() ? -0x7010 : -0x7008;
     const unsigned Reg = Subtarget.isPPC64() ? PPC::X13 : PPC::R2;
     MI.setDesc(get(Subtarget.isPPC64() ? PPC::LD : PPC::LWZ));
     MachineInstrBuilder(*MI.getParent()->getParent(), MI)