Merged main:902b2a26ab9e1e78dfb66b52fba4512c91472e09 into amd-gfx:9b007be77fcd

Local branch amd-gfx 9b007be Merged main:175aa864f33786f3a6a4ee7381cbcafd0758501a into amd-gfx:ad92d65754df
Remote branch main 902b2a2 [clang] Add lifetimebound attr to std::span/std::string_view constructor (llvm#103716)

Author: SC llvm team

clang/docs/ReleaseNotes.rst

@@ -220,6 +220,11 @@ Attribute Changes in Clang
 - ``[[clang::lifetimebound]]`` is now explicitly disallowed on explicit object member functions
   where they were previously silently ignored.
 
+- Clang now automatically adds ``[[clang::lifetimebound]]`` to the parameters of
+  ``std::span, std::string_view`` constructors, this enables Clang to capture
+  more cases where the returned reference outlives the object.
+  (#GH100567)
+
 Improvements to Clang's diagnostics
 -----------------------------------
 

clang/include/clang/Sema/Sema.h

@@ -1806,6 +1806,9 @@ class Sema final : public SemaBase {
   /// Add [[gsl::Owner]] and [[gsl::Pointer]] attributes for std:: types.
   void inferGslOwnerPointerAttribute(CXXRecordDecl *Record);
 
+  /// Add [[clang:::lifetimebound]] attr for std:: functions and methods.
+  void inferLifetimeBoundAttribute(FunctionDecl *FD);
+
   /// Add [[gsl::Pointer]] attributes for std:: types.
   void inferGslPointerAttribute(TypedefNameDecl *TD);
 

clang/lib/Sema/SemaAttr.cpp

@@ -216,6 +216,59 @@ void Sema::inferGslOwnerPointerAttribute(CXXRecordDecl *Record) {
   inferGslPointerAttribute(Record, Record);
 }
 
+void Sema::inferLifetimeBoundAttribute(FunctionDecl *FD) {
+  if (FD->getNumParams() == 0)
+    return;
+
+  if (unsigned BuiltinID = FD->getBuiltinID()) {
+    // Add lifetime attribute to std::move, std::fowrard et al.
+    switch (BuiltinID) {
+    case Builtin::BIaddressof:
+    case Builtin::BI__addressof:
+    case Builtin::BI__builtin_addressof:
+    case Builtin::BIas_const:
+    case Builtin::BIforward:
+    case Builtin::BIforward_like:
+    case Builtin::BImove:
+    case Builtin::BImove_if_noexcept:
+      if (ParmVarDecl *P = FD->getParamDecl(0u);
+          !P->hasAttr<LifetimeBoundAttr>())
+        P->addAttr(
+            LifetimeBoundAttr::CreateImplicit(Context, FD->getLocation()));
+      break;
+    default:
+      break;
+    }
+    return;
+  }
+  if (auto *CMD = dyn_cast<CXXMethodDecl>(FD)) {
+    const auto *CRD = CMD->getParent();
+    if (!CRD->isInStdNamespace() || !CRD->getIdentifier())
+      return;
+
+    if (isa<CXXConstructorDecl>(CMD)) {
+      auto *Param = CMD->getParamDecl(0);
+      if (Param->hasAttr<LifetimeBoundAttr>())
+        return;
+      if (CRD->getName() == "basic_string_view" &&
+          Param->getType()->isPointerType()) {
+        // construct from a char array pointed by a pointer.
+        //   basic_string_view(const CharT* s);
+        //   basic_string_view(const CharT* s, size_type count);
+        Param->addAttr(
+            LifetimeBoundAttr::CreateImplicit(Context, FD->getLocation()));
+      } else if (CRD->getName() == "span") {
+        // construct from a reference of array.
+        //   span(std::type_identity_t<element_type> (&arr)[N]);
+        const auto *LRT = Param->getType()->getAs<LValueReferenceType>();
+        if (LRT && LRT->getPointeeType().IgnoreParens()->isArrayType())
+          Param->addAttr(
+              LifetimeBoundAttr::CreateImplicit(Context, FD->getLocation()));
+      }
+    }
+  }
+}
+
 void Sema::inferNullableClassAttribute(CXXRecordDecl *CRD) {
   static const llvm::StringSet<> Nullable{
       "auto_ptr",         "shared_ptr", "unique_ptr",         "exception_ptr",

clang/lib/Sema/SemaDecl.cpp

@@ -16608,27 +16608,9 @@ void Sema::AddKnownFunctionAttributes(FunctionDecl *FD) {
     default:
       break;
     }
-
-    // Add lifetime attribute to std::move, std::fowrard et al.
-    switch (BuiltinID) {
-    case Builtin::BIaddressof:
-    case Builtin::BI__addressof:
-    case Builtin::BI__builtin_addressof:
-    case Builtin::BIas_const:
-    case Builtin::BIforward:
-    case Builtin::BIforward_like:
-    case Builtin::BImove:
-    case Builtin::BImove_if_noexcept:
-      if (ParmVarDecl *P = FD->getParamDecl(0u);
-          !P->hasAttr<LifetimeBoundAttr>())
-        P->addAttr(
-            LifetimeBoundAttr::CreateImplicit(Context, FD->getLocation()));
-      break;
-    default:
-      break;
-    }
   }
 
+  inferLifetimeBoundAttribute(FD);
   AddKnownFunctionAttributesForReplaceableGlobalAllocationFunction(FD);
 
   // If C++ exceptions are enabled but we are told extern "C" functions cannot

clang/test/SemaCXX/attr-lifetimebound.cpp

@@ -238,6 +238,16 @@ template <class T> T *addressof(T &arg) {
         &const_cast<char &>(reinterpret_cast<const volatile char &>(arg)));
 }
 
+template<typename T>
+struct basic_string_view {
+  basic_string_view(const T *);
+};
+
+template <class T> struct span {
+  template<size_t _ArrayExtent>
+	span(const T (&__arr)[_ArrayExtent]) noexcept;
+};
+
 } // namespace foo
 } // namespace std
 
@@ -266,3 +276,14 @@ namespace move_forward_et_al_examples {
   S *AddressOfOk = std::addressof(X);
 } // namespace move_forward_et_al_examples
 
+namespace ctor_cases {
+std::basic_string_view<char> test1() {
+  char abc[10];
+  return abc;  // expected-warning {{address of stack memory associated with local variable}}
+}
+
+std::span<int> test2() {
+  int abc[10];
+  return abc; // expected-warning {{address of stack memory associated with local variable}}
+}
+} // namespace ctor_cases

libcxx/include/__math/traits.h

@@ -127,14 +127,21 @@ _LIBCPP_NODISCARD inline _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI boo
 
 // isnormal
 
-template <class _A1, __enable_if_t<is_floating_point<_A1>::value, int> = 0>
+template <class _A1, __enable_if_t<is_integral<_A1>::value, int> = 0>
 _LIBCPP_NODISCARD _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool isnormal(_A1 __x) _NOEXCEPT {
+  return __x != 0;
+}
+
+_LIBCPP_NODISCARD inline _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool isnormal(float __x) _NOEXCEPT {
   return __builtin_isnormal(__x);
 }
 
-template <class _A1, __enable_if_t<is_integral<_A1>::value, int> = 0>
-_LIBCPP_NODISCARD _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool isnormal(_A1 __x) _NOEXCEPT {
-  return __x != 0;
+_LIBCPP_NODISCARD inline _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool isnormal(double __x) _NOEXCEPT {
+  return __builtin_isnormal(__x);
+}
+
+_LIBCPP_NODISCARD inline _LIBCPP_CONSTEXPR_SINCE_CXX23 _LIBCPP_HIDE_FROM_ABI bool isnormal(long double __x) _NOEXCEPT {
+  return __builtin_isnormal(__x);
 }
 
 // isgreater

libcxx/test/std/numerics/c.math/isnormal.pass.cpp

@@ -62,9 +62,23 @@ struct TestInt {
   }
 };
 
+template <typename T>
+struct ConvertibleTo {
+  operator T() const { return T(1); }
+};
+
 int main(int, char**) {
   types::for_each(types::floating_point_types(), TestFloat());
   types::for_each(types::integral_types(), TestInt());
 
+  // Make sure we can call `std::isnormal` with convertible types. This checks
+  // whether overloads for all cv-unqualified floating-point types are working
+  // as expected.
+  {
+    assert(std::isnormal(ConvertibleTo<float>()));
+    assert(std::isnormal(ConvertibleTo<double>()));
+    assert(std::isnormal(ConvertibleTo<long double>()));
+  }
+
   return 0;
 }

llvm/include/llvm/Config/llvm-config.h.cmake

@@ -16,7 +16,7 @@
 
 /* Indicate that this is LLVM compiled from the amd-gfx branch. */
 #define LLVM_HAVE_BRANCH_AMD_GFX
-#define LLVM_MAIN_REVISION 509868
+#define LLVM_MAIN_REVISION 509872
 
 /* Define if LLVM_ENABLE_DUMP is enabled */
 #cmakedefine LLVM_ENABLE_DUMP

llvm/lib/FileCheck/FileCheck.cpp

@@ -298,7 +298,7 @@ Pattern::parseVariable(StringRef &Str, const SourceMgr &SM) {
     ++I;
 
   if (I == Str.size())
-    return ErrorDiagnostic::get(SM, Str.slice(I, StringRef::npos),
+    return ErrorDiagnostic::get(SM, Str.substr(I),
                                 StringRef("empty ") +
                                     (IsPseudo ? "pseudo " : "global ") +
                                     "variable name");

llvm/lib/Target/AMDGPU/R600InstrInfo.cpp

@@ -75,12 +75,9 @@ void R600InstrInfo::copyPhysReg(MachineBasicBlock &MBB,
 /// \returns true if \p MBBI can be moved into a new basic.
 bool R600InstrInfo::isLegalToSplitMBBAt(MachineBasicBlock &MBB,
                                        MachineBasicBlock::iterator MBBI) const {
-  for (MachineInstr::const_mop_iterator I = MBBI->operands_begin(),
-                                        E = MBBI->operands_end(); I != E; ++I) {
-    if (I->isReg() && !I->getReg().isVirtual() && I->isUse() &&
-        RI.isPhysRegLiveAcrossClauses(I->getReg()))
+  for (const MachineOperand &MO : MBBI->all_uses())
+    if (!MO.getReg().isVirtual() && RI.isPhysRegLiveAcrossClauses(MO.getReg()))
       return false;
-  }
   return true;
 }
 
@@ -219,15 +216,10 @@ bool R600InstrInfo::readsLDSSrcReg(const MachineInstr &MI) const {
   if (!isALUInstr(MI.getOpcode())) {
     return false;
   }
-  for (MachineInstr::const_mop_iterator I = MI.operands_begin(),
-                                        E = MI.operands_end();
-       I != E; ++I) {
-    if (!I->isReg() || !I->isUse() || I->getReg().isVirtual())
-      continue;
-
-    if (R600::R600_LDS_SRC_REGRegClass.contains(I->getReg()))
+  for (const MachineOperand &MO : MI.all_uses())
+    if (MO.getReg().isPhysical() &&
+        R600::R600_LDS_SRC_REGRegClass.contains(MO.getReg()))
       return true;
-  }
   return false;
 }
 

llvm/tools/llvm-objcopy/ObjcopyOptions.cpp

@@ -556,9 +556,9 @@ static Expected<int64_t> parseChangeSectionLMA(StringRef ArgValue,
                                                StringRef OptionName) {
   StringRef StringValue;
   if (ArgValue.starts_with("*+")) {
-    StringValue = ArgValue.slice(2, StringRef::npos);
+    StringValue = ArgValue.substr(2);
   } else if (ArgValue.starts_with("*-")) {
-    StringValue = ArgValue.slice(1, StringRef::npos);
+    StringValue = ArgValue.substr(1);
   } else if (ArgValue.contains("=")) {
     return createStringError(errc::invalid_argument,
                              "bad format for " + OptionName +
@@ -608,7 +608,7 @@ parseChangeSectionAddr(StringRef ArgValue, StringRef OptionName,
           SectionPattern, SectionMatchStyle, ErrorCallback)))
     return std::move(E);
 
-  StringRef Value = ArgValue.slice(LastSymbolIndex + 1, StringRef::npos);
+  StringRef Value = ArgValue.substr(LastSymbolIndex + 1);
   if (Value.empty()) {
     switch (UpdateSymbol) {
     case '+':

llvm/unittests/Support/VirtualFileSystemTest.cpp

@@ -1583,7 +1583,7 @@ class VFSFromYAMLTest : public ::testing::Test {
       IntrusiveRefCntPtr<vfs::FileSystem> ExternalFS = new DummyFileSystem(),
       StringRef YAMLFilePath = "") {
     std::string VersionPlusContent("{\n  'version':0,\n");
-    VersionPlusContent += Content.slice(Content.find('{') + 1, StringRef::npos);
+    VersionPlusContent += Content.substr(Content.find('{') + 1);
     return getFromYAMLRawString(VersionPlusContent, ExternalFS, YAMLFilePath);
   }