[Sema] Issue diagnostics if a new/delete expression generates a call to

a c++17 aligned allocation/deallocation function that is unavailable in
the standard library on Apple platforms.

The aligned functions are implemented only in the following versions or
later versions of the OSes, so clang issues diagnostics if the deployment
target being targeted is older than these:

macosx: 10.13
ios: 11.0
tvos: 11.0
watchos: 4.0

The diagnostics are issued whenever the aligned functions are selected
except when the selected function has a definition in the same file.
If there is a user-defined function available somewhere else, option
-Wno-aligned-allocation-unavailable can be used to silence the
diagnostics.

rdar://problem/32664169

Differential Revision: https://reviews.llvm.org/D34574

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@306722 91177308-0d34-0410-b5e6-96231b3b80d8

5 files changed, 15 insertions, 1 deletions

diff --git a/include/clang/AST/Decl.h b/include/clang/AST/Decl.h
index 30552be9b3..08b34a75aa 100644
--- a/include/clang/AST/Decl.h
+++ b/include/clang/AST/Decl.h
@@ -2019,7 +2019,10 @@ public:
   /// These functions have special behavior under C++1y [expr.new]:
   ///    An implementation is allowed to omit a call to a replaceable global
   ///    allocation function. [...]
-  bool isReplaceableGlobalAllocationFunction() const;
+  ///
+  /// If this function is an aligned allocation/deallocation function, return
+  /// true through IsAligned.
+  bool isReplaceableGlobalAllocationFunction(bool *IsAligned = nullptr) const;
 
   /// Compute the language linkage.
   LanguageLinkage getLanguageLinkage() const;
diff --git a/include/clang/Basic/DiagnosticGroups.td b/include/clang/Basic/DiagnosticGroups.td
index 464c2425a1..3a0564806b 100644
--- a/include/clang/Basic/DiagnosticGroups.td
+++ b/include/clang/Basic/DiagnosticGroups.td
@@ -311,6 +311,7 @@ def : DiagGroup<"nonportable-cfstrings">;
 def NonVirtualDtor : DiagGroup<"non-virtual-dtor">;
 def : DiagGroup<"effc++", [NonVirtualDtor]>;
 def OveralignedType : DiagGroup<"over-aligned">;
+def AlignedAllocationUnavailable : DiagGroup<"aligned-allocation-unavailable">;
 def OldStyleCast : DiagGroup<"old-style-cast">;
 def : DiagGroup<"old-style-definition">;
 def OutOfLineDeclaration : DiagGroup<"out-of-line-declaration">;
diff --git a/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td
index 6224f13ce7..7b1671bb87 100644
--- a/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/include/clang/Basic/DiagnosticSemaKinds.td
@@ -6407,6 +6407,12 @@ def warn_overaligned_type : Warning<
   "type %0 requires %1 bytes of alignment and the default allocator only "
   "guarantees %2 bytes">,
   InGroup<OveralignedType>, DefaultIgnore;
+def warn_aligned_allocation_unavailable :Warning<
+  "aligned %select{allocation|deallocation}0 function of type '%1' possibly "
+  "unavailable on %2">, InGroup<AlignedAllocationUnavailable>, DefaultError;
+def note_silence_unligned_allocation_unavailable : Note<
+  "if you supply your own aligned allocation functions, use "
+  "-Wno-aligned-allocation-unavailable to silence this diagnostic">;
 
 def err_conditional_void_nonvoid : Error<
   "%select{left|right}1 operand to ? is void, but %select{right|left}1 operand "
diff --git a/include/clang/Basic/LangOptions.def b/include/clang/Basic/LangOptions.def
index 60c8a68cd2..dfdad10892 100644
--- a/include/clang/Basic/LangOptions.def
+++ b/include/clang/Basic/LangOptions.def
@@ -199,6 +199,7 @@ LANGOPT(CUDADeviceApproxTranscendentals, 1, 0, "using approximate transcendental
 
 LANGOPT(SizedDeallocation , 1, 0, "sized deallocation")
 LANGOPT(AlignedAllocation , 1, 0, "aligned allocation")
+LANGOPT(AlignedAllocationUnavailable, 1, 0, "aligned allocation functions are unavailable")
 LANGOPT(NewAlignOverride  , 32, 0, "maximum alignment guaranteed by '::operator new(size_t)'")
 LANGOPT(ConceptsTS , 1, 0, "enable C++ Extensions for Concepts")
 BENIGN_LANGOPT(ModulesCodegen , 1, 0, "Modules code generation")
diff --git a/include/clang/Driver/CC1Options.td b/include/clang/Driver/CC1Options.td
index c478cfc783..ab790c8a0a 100644
--- a/include/clang/Driver/CC1Options.td
+++ b/include/clang/Driver/CC1Options.td
@@ -568,6 +568,9 @@ def find_pch_source_EQ : Joined<["-"], "find-pch-source=">,
 def fno_pch_timestamp : Flag<["-"], "fno-pch-timestamp">,
   HelpText<"Disable inclusion of timestamp in precompiled headers">;
   
+def aligned_alloc_unavailable : Flag<["-"], "faligned-alloc-unavailable">,
+  HelpText<"Aligned allocation/deallocation functions are unavailable">;
+
 //===----------------------------------------------------------------------===//
 // Language Options
 //===----------------------------------------------------------------------===//