Replace llvm::isPodLike<...> by llvm::is_trivially_copyable<...>

As noted in https://bugs.llvm.org/show_bug.cgi?id=36651, the specialization for
isPodLike<std::pair<...>> did not match the expectation of
std::is_trivially_copyable which makes the memcpy optimization invalid.

This patch renames the llvm::isPodLike trait into llvm::is_trivially_copyable.
Unfortunately std::is_trivially_copyable is not portable across compiler / STL
versions. So a portable version is provided too.

Note that the following specialization were invalid:

    std::pair<T0, T1>
    llvm::Optional<T>

Tests have been added to assert that former specialization are respected by the
standard usage of llvm::is_trivially_copyable, and that when a decent version
of std::is_trivially_copyable is available, llvm::is_trivially_copyable is
compared to std::is_trivially_copyable.

As of this patch, llvm::Optional is no longer considered trivially copyable,
even if T is. This is to be fixed in a later patch, as it has impact on a
long-running bug (see r347004)

Note that GCC warns about this UB, but this got silented by https://reviews.llvm.org/D50296.

Differential Revision: https://reviews.llvm.org/D54472



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@351701 91177308-0d34-0410-b5e6-96231b3b80d8

14 files changed, 0 insertions, 73 deletions

diff --git a/include/clang/AST/BaseSubobject.h b/include/clang/AST/BaseSubobject.h
index 151678fbd3..15600f02fc 100644
--- a/include/clang/AST/BaseSubobject.h
+++ b/include/clang/AST/BaseSubobject.h
@@ -80,11 +80,6 @@ template<> struct DenseMapInfo<clang::BaseSubobject> {
   }
 };
 
-// It's OK to treat BaseSubobject as a POD type.
-template <> struct isPodLike<clang::BaseSubobject> {
-  static const bool value = true;
-};
-
 } // namespace llvm
 
 #endif // LLVM_CLANG_AST_BASESUBOBJECT_H
diff --git a/include/clang/AST/CharUnits.h b/include/clang/AST/CharUnits.h
index b029a1a3ab..37f489c770 100644
--- a/include/clang/AST/CharUnits.h
+++ b/include/clang/AST/CharUnits.h
@@ -237,10 +237,6 @@ template<> struct DenseMapInfo<clang::CharUnits> {
   }
 };
 
-template <> struct isPodLike<clang::CharUnits> {
-  static const bool value = true;
-};
-
 } // end namespace llvm
 
 #endif // LLVM_CLANG_AST_CHARUNITS_H
diff --git a/include/clang/AST/DeclAccessPair.h b/include/clang/AST/DeclAccessPair.h
index 9b33379341..805342c291 100644
--- a/include/clang/AST/DeclAccessPair.h
+++ b/include/clang/AST/DeclAccessPair.h
@@ -60,12 +60,4 @@ public:
 };
 }
 
-// Take a moment to tell SmallVector that DeclAccessPair is POD.
-namespace llvm {
-template<typename> struct isPodLike;
-template<> struct isPodLike<clang::DeclAccessPair> {
-   static const bool value = true;
-};
-}
-
 #endif
diff --git a/include/clang/AST/DeclarationName.h b/include/clang/AST/DeclarationName.h
index 22f6bf7f44..e5d34399f8 100644
--- a/include/clang/AST/DeclarationName.h
+++ b/include/clang/AST/DeclarationName.h
@@ -861,9 +861,6 @@ struct DenseMapInfo<clang::DeclarationName> {
   }
 };
 
-template <>
-struct isPodLike<clang::DeclarationName> { static const bool value = true; };
-
 } // namespace llvm
 
 #endif // LLVM_CLANG_AST_DECLARATIONNAME_H
diff --git a/include/clang/AST/ExprObjC.h b/include/clang/AST/ExprObjC.h
index b51935d0d7..debe5acebf 100644
--- a/include/clang/AST/ExprObjC.h
+++ b/include/clang/AST/ExprObjC.h
@@ -255,12 +255,6 @@ struct ObjCDictionaryElement {
 
 } // namespace clang
 
-namespace llvm {
-
-template <> struct isPodLike<clang::ObjCDictionaryElement> : std::true_type {};
-
-} // namespace llvm
-
 namespace clang {
 
 /// Internal struct for storing Key/value pair.
diff --git a/include/clang/AST/GlobalDecl.h b/include/clang/AST/GlobalDecl.h
index d6d8b11062..a5937c239e 100644
--- a/include/clang/AST/GlobalDecl.h
+++ b/include/clang/AST/GlobalDecl.h
@@ -139,13 +139,6 @@ namespace llvm {
     }
   };
 
-  // GlobalDecl isn't *technically* a POD type. However, its copy constructor,
-  // copy assignment operator, and destructor are all trivial.
-  template <>
-  struct isPodLike<clang::GlobalDecl> {
-    static const bool value = true;
-  };
-
 } // namespace llvm
 
 #endif // LLVM_CLANG_AST_GLOBALDECL_H
diff --git a/include/clang/AST/Type.h b/include/clang/AST/Type.h
index 58e2f60fe7..fbf91d3088 100644
--- a/include/clang/AST/Type.h
+++ b/include/clang/AST/Type.h
@@ -94,9 +94,6 @@ namespace llvm {
     enum { NumLowBitsAvailable = clang::TypeAlignmentInBits };
   };
 
-  template <>
-  struct isPodLike<clang::QualType> { static const bool value = true; };
-
 } // namespace llvm
 
 namespace clang {
diff --git a/include/clang/Analysis/ProgramPoint.h b/include/clang/Analysis/ProgramPoint.h
index 0f869233af..623f5dc707 100644
--- a/include/clang/Analysis/ProgramPoint.h
+++ b/include/clang/Analysis/ProgramPoint.h
@@ -777,9 +777,6 @@ static bool isEqual(const clang::ProgramPoint &L,
 
 };
 
-template <>
-struct isPodLike<clang::ProgramPoint> { static const bool value = true; };
-
 } // end namespace llvm
 
 #endif
diff --git a/include/clang/Basic/IdentifierTable.h b/include/clang/Basic/IdentifierTable.h
index c5ad0e5830..465486ede7 100644
--- a/include/clang/Basic/IdentifierTable.h
+++ b/include/clang/Basic/IdentifierTable.h
@@ -938,9 +938,6 @@ struct DenseMapInfo<clang::Selector> {
   }
 };
 
-template <>
-struct isPodLike<clang::Selector> { static const bool value = true; };
-
 template<>
 struct PointerLikeTypeTraits<clang::Selector> {
   static const void *getAsVoidPointer(clang::Selector P) {
diff --git a/include/clang/Basic/SourceLocation.h b/include/clang/Basic/SourceLocation.h
index 2b7f967d05..ceebdf4822 100644
--- a/include/clang/Basic/SourceLocation.h
+++ b/include/clang/Basic/SourceLocation.h
@@ -25,7 +25,6 @@
 namespace llvm {
 
 template <typename T> struct DenseMapInfo;
-template <typename T> struct isPodLike;
 
 } // namespace llvm
 
@@ -457,11 +456,6 @@ namespace llvm {
     }
   };
 
-  template <>
-  struct isPodLike<clang::SourceLocation> { static const bool value = true; };
-  template <>
-  struct isPodLike<clang::FileID> { static const bool value = true; };
-
   // Teach SmallPtrSet how to handle SourceLocation.
   template<>
   struct PointerLikeTypeTraits<clang::SourceLocation> {
diff --git a/include/clang/Lex/Token.h b/include/clang/Lex/Token.h
index 83f4433709..20483e393c 100644
--- a/include/clang/Lex/Token.h
+++ b/include/clang/Lex/Token.h
@@ -328,9 +328,4 @@ struct PPConditionalInfo {
 
 } // end namespace clang
 
-namespace llvm {
-  template <>
-  struct isPodLike<clang::Token> { static const bool value = true; };
-} // end namespace llvm
-
 #endif // LLVM_CLANG_LEX_TOKEN_H
diff --git a/include/clang/Sema/CodeCompleteConsumer.h b/include/clang/Sema/CodeCompleteConsumer.h
index 005d62ad00..5c14fb8773 100644
--- a/include/clang/Sema/CodeCompleteConsumer.h
+++ b/include/clang/Sema/CodeCompleteConsumer.h
@@ -655,14 +655,6 @@ public:
 
 } // namespace clang
 
-namespace llvm {
-
-template <> struct isPodLike<clang::CodeCompletionString::Chunk> {
-  static const bool value = true;
-};
-
-} // namespace llvm
-
 namespace clang {
 
 /// A builder class used to construct new code-completion strings.
diff --git a/include/clang/Sema/Ownership.h b/include/clang/Sema/Ownership.h
index 8a82c1382d..f395282c0c 100644
--- a/include/clang/Sema/Ownership.h
+++ b/include/clang/Sema/Ownership.h
@@ -128,9 +128,6 @@ namespace llvm {
     }
   };
 
-  template <class T>
-  struct isPodLike<clang::OpaquePtr<T>> { static const bool value = true; };
-
 } // namespace llvm
 
 namespace clang {
diff --git a/include/clang/StaticAnalyzer/Core/PathSensitive/SVals.h b/include/clang/StaticAnalyzer/Core/PathSensitive/SVals.h
index d956133d03..e859936621 100644
--- a/include/clang/StaticAnalyzer/Core/PathSensitive/SVals.h
+++ b/include/clang/StaticAnalyzer/Core/PathSensitive/SVals.h
@@ -667,13 +667,4 @@ private:
 
 } // namespace clang
 
-namespace llvm {
-
-template <typename T> struct isPodLike;
-template <> struct isPodLike<clang::ento::SVal> {
-  static const bool value = true;
-};
-
-} // namespace llvm
-
 #endif // LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_SVALS_H