PR libstdc++/68210 adjust operator new and delete for LWG 206

Ensure that nothrow versions of new and delete call the ordinary
versions of new or delete, instead of calling malloc or free directly.

These files are all compiled with -std=gnu++14 so can use noexcept and
nullptr to make the code more readable.

	PR libstdc++/68210
	* doc/xml/manual/intro.xml: Document LWG 206 change.
	* libsupc++/del_op.cc: Replace _GLIBCXX_USE_NOEXCEPT with noexcept.
	* libsupc++/del_opa.cc: Likewise.
	* libsupc++/del_opant.cc: Likewise.
	* libsupc++/del_opnt.cc: Likewise. Call operator delete(ptr) instead
	of free(ptr).
	* libsupc++/del_ops.cc: Replace _GLIBCXX_USE_NOEXCEPT with noexcept.
	* libsupc++/del_opsa.cc: Likewise.
	* libsupc++/del_opva.cc: Likewise.
	* libsupc++/del_opvant.cc: Likewise.
	* libsupc++/del_opvnt.cc: Likewise. Call operator delete[](ptr)
	instead of operator delete(ptr).
	* libsupc++/del_opvs.cc: Replace _GLIBCXX_USE_NOEXCEPT with noexcept.
	* libsupc++/del_opvsa.cc: Likewise.
	* libsupc++/new_op.cc: Use __builtin_expect in check for zero size.
	* libsupc++/new_opa.cc: Use nullptr instead of literal 0.
	* libsupc++/new_opant.cc: Likewise. Replace _GLIBCXX_USE_NOEXCEPT
	with noexcept.
	* libsupc++/new_opnt.cc: Likewise. Call operator new(sz) instead of
	malloc(sz).
	* libsupc++/new_opvant.cc: Use nullptr and noexcept.
	* libsupc++/new_opvnt.cc: Likewise. Call operator new[](sz) instead of
	operator new(sz, nothrow).
	* testsuite/18_support/new_nothrow.cc: New test.

From-SVN: r263478

17 files changed, 46 insertions, 45 deletions

diff --git a/libstdc++-v3/libsupc++/del_op.cc b/libstdc++-v3/libsupc++/del_op.cc
index 9a5cb82..ab3b617 100644
--- a/libstdc++-v3/libsupc++/del_op.cc
+++ b/libstdc++-v3/libsupc++/del_op.cc
@@ -44,7 +44,7 @@ _GLIBCXX_END_NAMESPACE_VERSION
 #pragma GCC diagnostic ignored "-Wsized-deallocation"
 
 _GLIBCXX_WEAK_DEFINITION void
-operator delete(void* ptr) _GLIBCXX_USE_NOEXCEPT
+operator delete(void* ptr) noexcept
 {
   std::free(ptr);
 }
diff --git a/libstdc++-v3/libsupc++/del_opa.cc b/libstdc++-v3/libsupc++/del_opa.cc
index 71f384d..2a1f0ab 100644
--- a/libstdc++-v3/libsupc++/del_opa.cc
+++ b/libstdc++-v3/libsupc++/del_opa.cc
@@ -44,7 +44,7 @@ _GLIBCXX_END_NAMESPACE_VERSION
 #pragma GCC diagnostic ignored "-Wsized-deallocation"
 
 _GLIBCXX_WEAK_DEFINITION void
-operator delete(void* ptr, std::align_val_t) _GLIBCXX_USE_NOEXCEPT
+operator delete(void* ptr, std::align_val_t) noexcept
 {
 #if _GLIBCXX_HAVE_ALIGNED_ALLOC || _GLIBCXX_HAVE_POSIX_MEMALIGN \
     || _GLIBCXX_HAVE_MEMALIGN
diff --git a/libstdc++-v3/libsupc++/del_opant.cc b/libstdc++-v3/libsupc++/del_opant.cc
index a4305a3..603d9f2 100644
--- a/libstdc++-v3/libsupc++/del_opant.cc
+++ b/libstdc++-v3/libsupc++/del_opant.cc
@@ -27,7 +27,7 @@
 #include "new"
 
 _GLIBCXX_WEAK_DEFINITION void
-operator delete (void *ptr, std::align_val_t al, const std::nothrow_t&) _GLIBCXX_USE_NOEXCEPT
+operator delete (void *ptr, std::align_val_t al, const std::nothrow_t&) noexcept
 {
   ::operator delete (ptr, al);
 }
diff --git a/libstdc++-v3/libsupc++/del_opnt.cc b/libstdc++-v3/libsupc++/del_opnt.cc
index 2bbcdc3..a276265 100644
--- a/libstdc++-v3/libsupc++/del_opnt.cc
+++ b/libstdc++-v3/libsupc++/del_opnt.cc
@@ -41,7 +41,10 @@ _GLIBCXX_END_NAMESPACE_VERSION
 #include "new"
 
 _GLIBCXX_WEAK_DEFINITION void
-operator delete (void *ptr, const std::nothrow_t&) _GLIBCXX_USE_NOEXCEPT
+operator delete (void *ptr, const std::nothrow_t&) noexcept
 {
-  std::free(ptr);
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // 206. operator new(size_t, nothrow) may become unlinked to ordinary
+  // operator new if ordinary version replaced
+  ::operator delete (ptr);
 }
diff --git a/libstdc++-v3/libsupc++/del_ops.cc b/libstdc++-v3/libsupc++/del_ops.cc
index 1fa24f2..e452c7c 100644
--- a/libstdc++-v3/libsupc++/del_ops.cc
+++ b/libstdc++-v3/libsupc++/del_ops.cc
@@ -28,7 +28,7 @@
 #include "new"
 
 _GLIBCXX_WEAK_DEFINITION void
-operator delete(void* ptr, std::size_t) _GLIBCXX_USE_NOEXCEPT
+operator delete(void* ptr, std::size_t) noexcept
 {
   ::operator delete (ptr);
 }
diff --git a/libstdc++-v3/libsupc++/del_opsa.cc b/libstdc++-v3/libsupc++/del_opsa.cc
index 1984fce..2cadb4b 100644
--- a/libstdc++-v3/libsupc++/del_opsa.cc
+++ b/libstdc++-v3/libsupc++/del_opsa.cc
@@ -27,7 +27,7 @@
 #include "new"
 
 _GLIBCXX_WEAK_DEFINITION void
-operator delete(void* ptr, std::size_t, std::align_val_t al) _GLIBCXX_USE_NOEXCEPT
+operator delete(void* ptr, std::size_t, std::align_val_t al) noexcept
 {
   ::operator delete (ptr, al);
 }
diff --git a/libstdc++-v3/libsupc++/del_opva.cc b/libstdc++-v3/libsupc++/del_opva.cc
index dc727b3..a539ccc 100644
--- a/libstdc++-v3/libsupc++/del_opva.cc
+++ b/libstdc++-v3/libsupc++/del_opva.cc
@@ -30,7 +30,7 @@
 #pragma GCC diagnostic ignored "-Wsized-deallocation"
 
 _GLIBCXX_WEAK_DEFINITION void
-operator delete[] (void *ptr, std::align_val_t al) _GLIBCXX_USE_NOEXCEPT
+operator delete[] (void *ptr, std::align_val_t al) noexcept
 {
   ::operator delete (ptr, al);
 }
diff --git a/libstdc++-v3/libsupc++/del_opvant.cc b/libstdc++-v3/libsupc++/del_opvant.cc
index 86406b2..892c8b7 100644
--- a/libstdc++-v3/libsupc++/del_opvant.cc
+++ b/libstdc++-v3/libsupc++/del_opvant.cc
@@ -27,7 +27,7 @@
 #include "new"
 
 _GLIBCXX_WEAK_DEFINITION void
-operator delete[] (void *ptr, std::align_val_t al, const std::nothrow_t&) _GLIBCXX_USE_NOEXCEPT
+operator delete[] (void *ptr, std::align_val_t al, const std::nothrow_t&) noexcept
 {
   ::operator delete[] (ptr, al);
 }
diff --git a/libstdc++-v3/libsupc++/del_opvnt.cc b/libstdc++-v3/libsupc++/del_opvnt.cc
index ed06d2e..f050526 100644
--- a/libstdc++-v3/libsupc++/del_opvnt.cc
+++ b/libstdc++-v3/libsupc++/del_opvnt.cc
@@ -27,7 +27,7 @@
 #include "new"
 
 _GLIBCXX_WEAK_DEFINITION void
-operator delete[] (void *ptr, const std::nothrow_t&) _GLIBCXX_USE_NOEXCEPT
+operator delete[] (void *ptr, const std::nothrow_t&) noexcept
 {
-  ::operator delete (ptr);
+  ::operator delete[] (ptr);
 }
diff --git a/libstdc++-v3/libsupc++/del_opvs.cc b/libstdc++-v3/libsupc++/del_opvs.cc
index 2be94d6..4b1e161 100644
--- a/libstdc++-v3/libsupc++/del_opvs.cc
+++ b/libstdc++-v3/libsupc++/del_opvs.cc
@@ -28,7 +28,7 @@
 #include "new"
 
 _GLIBCXX_WEAK_DEFINITION void
-operator delete[] (void *ptr, std::size_t) _GLIBCXX_USE_NOEXCEPT
+operator delete[] (void *ptr, std::size_t) noexcept
 {
   ::operator delete[] (ptr);
 }
diff --git a/libstdc++-v3/libsupc++/del_opvsa.cc b/libstdc++-v3/libsupc++/del_opvsa.cc
index 02f1845..00ea369 100644
--- a/libstdc++-v3/libsupc++/del_opvsa.cc
+++ b/libstdc++-v3/libsupc++/del_opvsa.cc
@@ -27,7 +27,7 @@
 #include "new"
 
 _GLIBCXX_WEAK_DEFINITION void
-operator delete[] (void *ptr, std::size_t, std::align_val_t al) _GLIBCXX_USE_NOEXCEPT
+operator delete[] (void *ptr, std::size_t, std::align_val_t al) noexcept
 {
   ::operator delete[] (ptr, al);
 }
diff --git a/libstdc++-v3/libsupc++/new_op.cc b/libstdc++-v3/libsupc++/new_op.cc
index 3caa0ba..df77950 100644
--- a/libstdc++-v3/libsupc++/new_op.cc
+++ b/libstdc++-v3/libsupc++/new_op.cc
@@ -44,7 +44,7 @@ operator new (std::size_t sz) _GLIBCXX_THROW (std::bad_alloc)
   void *p;
 
   /* malloc (0) is unpredictable; avoid it.  */
-  if (sz == 0)
+  if (__builtin_expect (sz == 0, false))
     sz = 1;
 
   while ((p = malloc (sz)) == 0)
diff --git a/libstdc++-v3/libsupc++/new_opa.cc b/libstdc++-v3/libsupc++/new_opa.cc
index a27ff84..aa3e5dc 100644
--- a/libstdc++-v3/libsupc++/new_opa.cc
+++ b/libstdc++-v3/libsupc++/new_opa.cc
@@ -101,7 +101,6 @@ aligned_alloc (std::size_t al, std::size_t sz)
 _GLIBCXX_WEAK_DEFINITION void *
 operator new (std::size_t sz, std::align_val_t al)
 {
-  void *p;
   std::size_t align = (std::size_t)al;
 
   /* Alignment must be a power of two.  */
@@ -125,8 +124,9 @@ operator new (std::size_t sz, std::align_val_t al)
     sz += align - rem;
 #endif
 
-  using __gnu_cxx::aligned_alloc;
-  while ((p = aligned_alloc (align, sz)) == 0)
+  void *p;
+
+  while ((p = __gnu_cxx::aligned_alloc (align, sz)) == nullptr)
     {
       new_handler handler = std::get_new_handler ();
       if (! handler)
diff --git a/libstdc++-v3/libsupc++/new_opant.cc b/libstdc++-v3/libsupc++/new_opant.cc
index b445840..f08ae0c 100644
--- a/libstdc++-v3/libsupc++/new_opant.cc
+++ b/libstdc++-v3/libsupc++/new_opant.cc
@@ -29,7 +29,7 @@
 
 _GLIBCXX_WEAK_DEFINITION void*
 operator new(std::size_t sz, std::align_val_t al, const std::nothrow_t&)
-  _GLIBCXX_USE_NOEXCEPT
+  noexcept
 {
   __try
     {
@@ -37,6 +37,6 @@ operator new(std::size_t sz, std::align_val_t al, const std::nothrow_t&)
     }
   __catch(...)
     {
-      return 0;
+      return nullptr;
     }
 }
diff --git a/libstdc++-v3/libsupc++/new_opnt.cc b/libstdc++-v3/libsupc++/new_opnt.cc
index faab44e..ffe44b9 100644
--- a/libstdc++-v3/libsupc++/new_opnt.cc
+++ b/libstdc++-v3/libsupc++/new_opnt.cc
@@ -32,28 +32,17 @@ using std::bad_alloc;
 extern "C" void *malloc (std::size_t);
 
 _GLIBCXX_WEAK_DEFINITION void *
-operator new (std::size_t sz, const std::nothrow_t&) _GLIBCXX_USE_NOEXCEPT
+operator new (std::size_t sz, const std::nothrow_t&) noexcept
 {
-  void *p;
-
-  /* malloc (0) is unpredictable; avoid it.  */
-  if (sz == 0)
-    sz = 1;
-
-  while ((p = malloc (sz)) == 0)
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // 206. operator new(size_t, nothrow) may become unlinked to ordinary
+  // operator new if ordinary version replaced
+  __try
     {
-      new_handler handler = std::get_new_handler ();
-      if (! handler)
-	return 0;
-      __try
-	{
-	  handler ();
-	}
-      __catch(const bad_alloc&)
-	{
-	  return 0;
-	}
+      return ::operator new(sz);
+    }
+  __catch (...)
+    {
+      return nullptr;
     }
-
-  return p;
 }
diff --git a/libstdc++-v3/libsupc++/new_opvant.cc b/libstdc++-v3/libsupc++/new_opvant.cc
index faeb4dc..4ba1268 100644
--- a/libstdc++-v3/libsupc++/new_opvant.cc
+++ b/libstdc++-v3/libsupc++/new_opvant.cc
@@ -29,7 +29,7 @@
 
 _GLIBCXX_WEAK_DEFINITION void*
 operator new[] (std::size_t sz, std::align_val_t al, const std::nothrow_t&)
-  _GLIBCXX_USE_NOEXCEPT
+  noexcept
 {
   __try
     {
@@ -37,6 +37,6 @@ operator new[] (std::size_t sz, std::align_val_t al, const std::nothrow_t&)
     }
   __catch(...)
     {
-      return 0;
+      return nullptr;
     }
 }
diff --git a/libstdc++-v3/libsupc++/new_opvnt.cc b/libstdc++-v3/libsupc++/new_opvnt.cc
index 828a971..3678b8e 100644
--- a/libstdc++-v3/libsupc++/new_opvnt.cc
+++ b/libstdc++-v3/libsupc++/new_opvnt.cc
@@ -27,8 +27,17 @@
 #include "new"
  
 _GLIBCXX_WEAK_DEFINITION void*
-operator new[] (std::size_t sz, const std::nothrow_t& nothrow)
-  _GLIBCXX_USE_NOEXCEPT
+operator new[] (std::size_t sz, const std::nothrow_t&) noexcept
 {
-  return ::operator new(sz, nothrow);
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // 206. operator new(size_t, nothrow) may become unlinked to ordinary
+  // operator new if ordinary version replaced
+  __try
+    {
+      return ::operator new[](sz);
+    }
+  __catch (...)
+    {
+      return nullptr;
+    }
 }