RuntimeLibcalls: Add entries for stackprotector globals (llvm#154930)

Add entries for_stack_chk_guard, __ssp_canary_word, __security_cookie,
and __guard_local. As far as I can tell these are all just different
names for the same shaped functionality on different systems.

These aren't really functions, but special global variable names. They
should probably be treated the same way; all the same contexts that
need to know about emittable function names also need to know about
this. This avoids a special case check in IRSymtab.

This isn't a complete change, there's a lot more cleanup which
should be done. The stack protector configuration system is a
complete mess. There are multiple overlapping controls, used in
3 different places. Some of the target control implementations overlap
with conditions used in the emission points, and some use correlated
but not identical conditions in different contexts.

i.e. useLoadStackGuardNode, getIRStackGuard, getSSPStackGuardCheck and
insertSSPDeclarations are all used in inconsistent ways so I don't know
if I've tracked the intention of the system correctly.

The PowerPC test change is a bug fix on linux. Previously the manual
conditions were based around !isOSOpenBSD, which is not the condition
where __stack_chk_guard are used. Now getSDagStackGuard returns the
proper global reference, resulting in LOAD_STACK_GUARD getting a
MachineMemOperand which allows scheduling.

Author: arsenm

llvm/include/llvm/IR/RuntimeLibcalls.td

@@ -21,13 +21,20 @@ def isOSOpenBSD : RuntimeLibcallPredicate<"TT.isOSOpenBSD()">;
 def isNotOSOpenBSD : RuntimeLibcallPredicate<"!TT.isOSOpenBSD()">;
 def isOSWindows : RuntimeLibcallPredicate<"TT.isOSWindows()">;
 def isNotOSWindows : RuntimeLibcallPredicate<"!TT.isOSWindows()">;
+def isNotOSLinux : RuntimeLibcallPredicate<[{!TT.isOSLinux()}]>;
 def isNotOSMSVCRT : RuntimeLibcallPredicate<"!TT.isOSMSVCRT()">;
 def isPS : RuntimeLibcallPredicate<"TT.isPS()">;
 def isNotOSWindowsOrIsCygwinMinGW
   : RuntimeLibcallPredicate<"!TT.isOSWindows() || TT.isOSCygMing()">;
 def isWindowsMSVCEnvironment : RuntimeLibcallPredicate<
   [{TT.isWindowsMSVCEnvironment()}]>;
 
+def isNotOSLinuxAndNotOSOpenBSD : RuntimeLibcallPredicate<
+  [{!TT.isOSLinux() && !TT.isOSOpenBSD()}]>;
+
+def isWindowsMSVCOrItaniumEnvironment : RuntimeLibcallPredicate<
+  [{TT.isWindowsMSVCEnvironment() || TT.isWindowsItaniumEnvironment()}]>;
+
 def isGNUEnvironment : RuntimeLibcallPredicate<"TT.isGNUEnvironment()">;
 def darwinHasSinCosStret : RuntimeLibcallPredicate<"darwinHasSinCosStret(TT)">;
 def darwinHasExp10 : RuntimeLibcallPredicate<"darwinHasExp10(TT)">;
@@ -471,6 +478,16 @@ def OBJC_RETAIN_AUTORELEASE : RuntimeLibcall;
 def OBJC_SYNC_ENTER : RuntimeLibcall;
 def OBJC_SYNC_EXIT : RuntimeLibcall;
 
+//--------------------------------------------------------------------
+// Global variable references
+//--------------------------------------------------------------------
+//
+// TODO: These are not libcalls and probably should be distinguished
+// in some way from callable functions.
+// --------------------------------------------------------------------
+
+def STACK_CHECK_GUARD : RuntimeLibcall;
+
 //--------------------------------------------------------------------
 // Define implementation default libcalls
 //--------------------------------------------------------------------
@@ -1103,6 +1120,21 @@ defset list<RuntimeLibcallImpl> LibmF128FiniteLibcalls = {
   def __powf128_finite : RuntimeLibcallImpl<POW_FINITE_F128>;
 }
 
+//--------------------------------------------------------------------
+// Global variable references
+//--------------------------------------------------------------------
+
+def __stack_chk_guard : RuntimeLibcallImpl<STACK_CHECK_GUARD>;
+
+// Name used on OpenBSD
+def __guard_local : RuntimeLibcallImpl<STACK_CHECK_GUARD>;
+
+// Name used with Windows MSVC
+def __security_cookie : RuntimeLibcallImpl<STACK_CHECK_GUARD>;
+
+// Name used on AIX
+def __ssp_canary_word : RuntimeLibcallImpl<STACK_CHECK_GUARD>;
+
 //===----------------------------------------------------------------------===//
 // Common Libcall Sets
 //===----------------------------------------------------------------------===//
@@ -1159,7 +1191,8 @@ defvar DarwinSinCosStret = LibcallImpls<(add __sincosf_stret, __sincos_stret),
 defvar DarwinExp10 = LibcallImpls<(add __exp10f, __exp10), darwinHasExp10>;
 
 defvar SecurityCheckCookieIfWinMSVC =
-    LibcallImpls<(add __security_check_cookie), isWindowsMSVCEnvironment>;
+    LibcallImpls<(add __security_check_cookie, __security_cookie),
+                 isWindowsMSVCOrItaniumEnvironment>;
 
 defvar LibmHasSinCosF32 = LibcallImpls<(add sincosf), hasSinCos>;
 defvar LibmHasSinCosF64 =  LibcallImpls<(add sincos), hasSinCos>;
@@ -1205,10 +1238,13 @@ defvar LibmHasFrexpF128 = LibcallImpls<(add frexp_f128), isNotOSWindowsOrIsCygwi
 defvar LibmHasLdexpF128 = LibcallImpls<(add ldexp_f128), isNotOSWindowsOrIsCygwinMinGW>;
 
 defvar has__stack_chk_fail = LibcallImpls<(add __stack_chk_fail), isNotOSOpenBSD>;
+defvar has__stack_chk_guard =
+    LibcallImpls<(add __stack_chk_guard), isNotOSOpenBSD>;
 defvar has__stack_smash_handler = LibcallImpls<(add __stack_smash_handler), isOSOpenBSD>;
+defvar has___guard_local = LibcallImpls<(add __guard_local), isOSOpenBSD>;
 
-defvar DefaultStackProtector = (add has__stack_chk_fail,
-                                    has__stack_smash_handler);
+defvar DefaultStackProtector = (add has__stack_chk_fail, has__stack_chk_guard,
+    has__stack_smash_handler, has___guard_local);
 
 //===----------------------------------------------------------------------===//
 // Objective-C Runtime Libcalls
@@ -1357,7 +1393,9 @@ def WindowsARM64ECSystemLibrary
     : SystemRuntimeLibrary<isWindowsArm64EC,
                            (add WinArm64ECDefaultRuntimeLibcallImpls,
                                 arm64ec___stack_chk_fail,
-                                LibcallImpls<(add __security_check_cookie_arm64ec),
+                                __stack_chk_guard,
+                                LibcallImpls<(add __security_check_cookie_arm64ec,
+                                                  __security_cookie),
                                               isWindowsMSVCEnvironment>,
                                 ExceptionModelCallsArm64EC)>;
 
@@ -1848,7 +1886,7 @@ def HexagonSystemLibrary
     __umoddi3, __divdf3, __muldf3, __divsi3, __subdf3, sqrtf,
     __divdi3, __umodsi3, __moddi3, __modsi3), HexagonLibcalls,
     LibmHasSinCosF32, LibmHasSinCosF64, LibmHasSinCosF128,
-    exp10f, exp10, exp10l_f128, __stack_chk_fail)>;
+    exp10f, exp10, exp10l_f128, __stack_chk_fail, __stack_chk_guard)>;
 
 //===----------------------------------------------------------------------===//
 // Lanai Runtime Libcalls
@@ -1859,7 +1897,7 @@ def isLanai : RuntimeLibcallPredicate<"TT.getArch() == Triple::lanai">;
 // Use fast calling convention for library functions.
 def LanaiSystemLibrary
     : SystemRuntimeLibrary<isLanai, (add DefaultRuntimeLibcallImpls,
-                                         __stack_chk_fail)> {
+                                        __stack_chk_fail, __stack_chk_guard)> {
   let DefaultLibcallCallingConv = FASTCC;
 }
 
@@ -2157,7 +2195,8 @@ def MSP430SystemLibrary
       __mspabi_slll,
       // __mspabi_[srlll/srall/sllll/rlli/rlll] are NOT implemented in libgcc
 
-      __stack_chk_fail
+      __stack_chk_fail,
+      __stack_chk_guard
   )
 >;
 
@@ -2251,7 +2290,11 @@ def PPCSystemLibrary
            LibmHasSinCosPPCF128,
            AvailableIf<memcpy, isNotAIX>,
            LibcallImpls<(add Int128RTLibcalls), isPPC64>,
-           DefaultStackProtector)>;
+           has__stack_chk_fail,
+           has__stack_smash_handler,
+           has___guard_local,
+           AvailableIf<__ssp_canary_word, isAIX>,
+           AvailableIf<__stack_chk_guard, isNotAIX>)>;
 
 //===----------------------------------------------------------------------===//
 // RISCV Runtime Libcalls
@@ -2334,7 +2377,10 @@ def SPARCSystemLibrary
        LibcallImpls<(add _Q_qtoll, _Q_qtoull, _Q_lltoq, _Q_ulltoq), isSPARC32>,
        LibcallImpls<(add SPARC64_MulDivCalls, Int128RTLibcalls), isSPARC64>,
        LibmHasSinCosF32, LibmHasSinCosF64, LibmHasSinCosF128,
-       DefaultStackProtector)
+       has__stack_chk_fail,
+       has__stack_smash_handler,
+       has___guard_local,
+       AvailableIf<__stack_chk_guard, isNotOSLinuxAndNotOSOpenBSD>)
 >;
 
 //===----------------------------------------------------------------------===//
@@ -2544,7 +2590,7 @@ def WasmSystemLibrary
            exp10f, exp10,
            _Unwind_CallPersonality,
            emscripten_return_address,
-           __stack_chk_fail)>;
+           __stack_chk_fail, __stack_chk_guard)>;
 
 //===----------------------------------------------------------------------===//
 // Legacy Default Runtime Libcalls

llvm/lib/CodeGen/TargetLoweringBase.cpp

@@ -2059,29 +2059,37 @@ Value *TargetLoweringBase::getIRStackGuard(IRBuilderBase &IRB) const {
 // Currently only support "standard" __stack_chk_guard.
 // TODO: add LOAD_STACK_GUARD support.
 void TargetLoweringBase::insertSSPDeclarations(Module &M) const {
-  if (!M.getNamedValue("__stack_chk_guard")) {
-    auto *GV = new GlobalVariable(M, PointerType::getUnqual(M.getContext()),
-                                  false, GlobalVariable::ExternalLinkage,
-                                  nullptr, "__stack_chk_guard");
-
-    // FreeBSD has "__stack_chk_guard" defined externally on libc.so
-    if (M.getDirectAccessExternalData() &&
-        !TM.getTargetTriple().isOSCygMing() &&
-        !(TM.getTargetTriple().isPPC64() &&
-          TM.getTargetTriple().isOSFreeBSD()) &&
-        (!TM.getTargetTriple().isOSDarwin() ||
-         TM.getRelocationModel() == Reloc::Static))
-      GV->setDSOLocal(true);
-  }
+  RTLIB::LibcallImpl StackGuardImpl = getLibcallImpl(RTLIB::STACK_CHECK_GUARD);
+  if (StackGuardImpl == RTLIB::Unsupported)
+    return;
+
+  StringRef StackGuardVarName = getLibcallImplName(StackGuardImpl);
+  M.getOrInsertGlobal(
+      StackGuardVarName, PointerType::getUnqual(M.getContext()), [=, &M]() {
+        auto *GV = new GlobalVariable(M, PointerType::getUnqual(M.getContext()),
+                                      false, GlobalVariable::ExternalLinkage,
+                                      nullptr, StackGuardVarName);
+
+        // FreeBSD has "__stack_chk_guard" defined externally on libc.so
+        if (M.getDirectAccessExternalData() &&
+            !TM.getTargetTriple().isOSCygMing() &&
+            !(TM.getTargetTriple().isPPC64() &&
+              TM.getTargetTriple().isOSFreeBSD()) &&
+            (!TM.getTargetTriple().isOSDarwin() ||
+             TM.getRelocationModel() == Reloc::Static))
+          GV->setDSOLocal(true);
+
+        return GV;
+      });
 }
 
 // Currently only support "standard" __stack_chk_guard.
 // TODO: add LOAD_STACK_GUARD support.
 Value *TargetLoweringBase::getSDagStackGuard(const Module &M) const {
-  if (getTargetMachine().getTargetTriple().isOSOpenBSD()) {
-    return M.getNamedValue("__guard_local");
-  }
-  return M.getNamedValue("__stack_chk_guard");
+  RTLIB::LibcallImpl GuardVarImpl = getLibcallImpl(RTLIB::STACK_CHECK_GUARD);
+  if (GuardVarImpl == RTLIB::Unsupported)
+    return nullptr;
+  return M.getNamedValue(getLibcallImplName(GuardVarImpl));
 }
 
 Function *TargetLoweringBase::getSSPStackGuardCheck(const Module &M) const {

llvm/lib/Object/IRSymtab.cpp

@@ -46,18 +46,6 @@ static cl::opt<bool> DisableBitcodeVersionUpgrade(
     "disable-bitcode-version-upgrade", cl::Hidden,
     cl::desc("Disable automatic bitcode upgrade for version mismatch"));
 
-static constexpr StringLiteral PreservedSymbols[] = {
-    // There are global variables, so put it here instead of in
-    // RuntimeLibcalls.td.
-    // TODO: Are there similar such variables?
-    "__ssp_canary_word",
-    "__stack_chk_guard",
-};
-
-static bool isPreservedGlobalVarName(StringRef Name) {
-  return PreservedSymbols[0] == Name || PreservedSymbols[1] == Name;
-}
-
 namespace {
 
 const char *getExpectedProducerName() {
@@ -106,7 +94,7 @@ struct Builder {
 
   std::vector<storage::Str> DependentLibraries;
 
-  bool isPreservedLibFuncName(StringRef Name) {
+  bool isPreservedName(StringRef Name) {
     return Libcalls.getSupportedLibcallImpl(Name) != RTLIB::Unsupported;
   }
 
@@ -281,8 +269,7 @@ Error Builder::addSymbol(const ModuleSymbolTable &Msymtab,
   StringRef GVName = GV->getName();
   setStr(Sym.IRName, GVName);
 
-  if (Used.count(GV) || isPreservedLibFuncName(GVName) ||
-      isPreservedGlobalVarName(GVName))
+  if (Used.count(GV) || isPreservedName(GVName))
     Sym.Flags |= 1 << storage::Symbol::FB_used;
   if (GV->isThreadLocal())
     Sym.Flags |= 1 << storage::Symbol::FB_tls;

llvm/lib/Target/AArch64/AArch64ISelLowering.cpp

@@ -28686,9 +28686,13 @@ void AArch64TargetLowering::insertSSPDeclarations(Module &M) const {
   // MSVC CRT provides functionalities for stack protection.
   RTLIB::LibcallImpl SecurityCheckCookieLibcall =
       getLibcallImpl(RTLIB::SECURITY_CHECK_COOKIE);
-  if (SecurityCheckCookieLibcall != RTLIB::Unsupported) {
+
+  RTLIB::LibcallImpl SecurityCookieVar =
+      getLibcallImpl(RTLIB::STACK_CHECK_GUARD);
+  if (SecurityCheckCookieLibcall != RTLIB::Unsupported &&
+      SecurityCookieVar != RTLIB::Unsupported) {
     // MSVC CRT has a global variable holding security cookie.
-    M.getOrInsertGlobal("__security_cookie",
+    M.getOrInsertGlobal(getLibcallImplName(SecurityCookieVar),
                         PointerType::getUnqual(M.getContext()));
 
     // MSVC CRT has a function to validate security cookie.
@@ -28705,13 +28709,6 @@ void AArch64TargetLowering::insertSSPDeclarations(Module &M) const {
   TargetLowering::insertSSPDeclarations(M);
 }
 
-Value *AArch64TargetLowering::getSDagStackGuard(const Module &M) const {
-  // MSVC CRT has a global variable holding security cookie.
-  if (Subtarget->getTargetTriple().isWindowsMSVCEnvironment())
-    return M.getGlobalVariable("__security_cookie");
-  return TargetLowering::getSDagStackGuard(M);
-}
-
 Function *AArch64TargetLowering::getSSPStackGuardCheck(const Module &M) const {
   // MSVC CRT has a function to validate security cookie.
   RTLIB::LibcallImpl SecurityCheckCookieLibcall =

llvm/lib/Target/AArch64/AArch64ISelLowering.h

@@ -354,7 +354,6 @@ class AArch64TargetLowering : public TargetLowering {
   Value *getIRStackGuard(IRBuilderBase &IRB) const override;
 
   void insertSSPDeclarations(Module &M) const override;
-  Value *getSDagStackGuard(const Module &M) const override;
   Function *getSSPStackGuardCheck(const Module &M) const override;
 
   /// If the target has a standard location for the unsafe stack pointer,

llvm/lib/Target/ARM/ARMISelLowering.cpp

@@ -21341,20 +21341,6 @@ void ARMTargetLowering::insertSSPDeclarations(Module &M) const {
     F->addParamAttr(0, Attribute::AttrKind::InReg);
 }
 
-Value *ARMTargetLowering::getSDagStackGuard(const Module &M) const {
-  RTLIB::LibcallImpl SecurityCheckCookieLibcall =
-      getLibcallImpl(RTLIB::SECURITY_CHECK_COOKIE);
-  if (SecurityCheckCookieLibcall != RTLIB::Unsupported) {
-    // MSVC CRT has a global variable holding security cookie.
-    //
-    // FIXME: We have a libcall entry for the correlated check function, but not
-    // the global name.
-    return M.getGlobalVariable("__security_cookie");
-  }
-
-  return TargetLowering::getSDagStackGuard(M);
-}
-
 Function *ARMTargetLowering::getSSPStackGuardCheck(const Module &M) const {
   // MSVC CRT has a function to validate security cookie.
   RTLIB::LibcallImpl SecurityCheckCookie =

llvm/lib/Target/ARM/ARMISelLowering.h

@@ -704,7 +704,6 @@ class VectorType;
     bool useLoadStackGuardNode(const Module &M) const override;
 
     void insertSSPDeclarations(Module &M) const override;
-    Value *getSDagStackGuard(const Module &M) const override;
     Function *getSSPStackGuardCheck(const Module &M) const override;
 
     bool canCombineStoreAndExtract(Type *VectorTy, Value *Idx,

llvm/lib/Target/PowerPC/PPCISelLowering.cpp

@@ -157,8 +157,6 @@ static bool isNByteElemShuffleMask(ShuffleVectorSDNode *, unsigned, int);
 
 static SDValue widenVec(SelectionDAG &DAG, SDValue Vec, const SDLoc &dl);
 
-static const char AIXSSPCanaryWordName[] = "__ssp_canary_word";
-
 // A faster local-[exec|dynamic] TLS access sequence (enabled with the
 // -maix-small-local-[exec|dynamic]-tls option) can be produced for TLS
 // variables; consistent with the IBM XL compiler, we apply a max size of
@@ -18655,24 +18653,6 @@ bool PPCTargetLowering::useLoadStackGuardNode(const Module &M) const {
   return TargetLowering::useLoadStackGuardNode(M);
 }
 
-// Override to disable global variable loading on Linux and insert AIX canary
-// word declaration.
-void PPCTargetLowering::insertSSPDeclarations(Module &M) const {
-  if (Subtarget.isAIXABI()) {
-    M.getOrInsertGlobal(AIXSSPCanaryWordName,
-                        PointerType::getUnqual(M.getContext()));
-    return;
-  }
-  if (!Subtarget.isTargetLinux())
-    return TargetLowering::insertSSPDeclarations(M);
-}
-
-Value *PPCTargetLowering::getSDagStackGuard(const Module &M) const {
-  if (Subtarget.isAIXABI())
-    return M.getGlobalVariable(AIXSSPCanaryWordName);
-  return TargetLowering::getSDagStackGuard(M);
-}
-
 bool PPCTargetLowering::isFPImmLegal(const APFloat &Imm, EVT VT,
                                      bool ForCodeSize) const {
   if (!VT.isSimple() || !Subtarget.hasVSX())

llvm/lib/Target/PowerPC/PPCISelLowering.h

@@ -1141,8 +1141,6 @@ namespace llvm {
 
     /// Override to support customized stack guard loading.
     bool useLoadStackGuardNode(const Module &M) const override;
-    void insertSSPDeclarations(Module &M) const override;
-    Value *getSDagStackGuard(const Module &M) const override;
 
     bool isFPImmLegal(const APFloat &Imm, EVT VT,
                       bool ForCodeSize) const override;

llvm/lib/Target/Sparc/SparcISelLowering.cpp

@@ -3549,12 +3549,6 @@ bool SparcTargetLowering::isFMAFasterThanFMulAndFAdd(const MachineFunction &MF,
   return Subtarget->isUA2007() && !Subtarget->useSoftFloat();
 }
 
-// Override to disable global variable loading on Linux.
-void SparcTargetLowering::insertSSPDeclarations(Module &M) const {
-  if (!Subtarget->isTargetLinux())
-    return TargetLowering::insertSSPDeclarations(M);
-}
-
 void SparcTargetLowering::AdjustInstrPostInstrSelection(MachineInstr &MI,
                                                         SDNode *Node) const {
   assert(MI.getOpcode() == SP::SUBCCrr || MI.getOpcode() == SP::SUBCCri);