Revert r237766, "Support: Introduce LLVM_FALLTHROUGH macro."

[oota-llvm.git] / include / llvm / Support / Compiler.h

diff --git a/include/llvm/Support/Compiler.h b/include/llvm/Support/Compiler.h
index 8534316600a166ae42ddf23d044f5f6d59968bbb..c81fbaff9dba89f4ac5966a50efb432131415c45 100644 (file)
--- a/include/llvm/Support/Compiler.h
+++ b/include/llvm/Support/Compiler.h
@@ -72,20 +72,20 @@
 #define LLVM_NOEXCEPT
 #endif
 
-/// \brief Does the compiler support r-value reference *this?
+/// \brief Does the compiler support ref-qualifiers for *this?
 ///
-/// Sadly, this is separate from just r-value reference support because GCC
-/// implemented this later than everything else.
+/// Sadly, this is separate from just rvalue reference support because GCC
+/// and MSVC implemented this later than everything else.
 #if __has_feature(cxx_rvalue_references) || LLVM_GNUC_PREREQ(4, 8, 1)
 #define LLVM_HAS_RVALUE_REFERENCE_THIS 1
 #else
 #define LLVM_HAS_RVALUE_REFERENCE_THIS 0
 #endif
 
-/// Expands to '&' if r-value references are supported.
+/// Expands to '&' if ref-qualifiers for *this are supported.
 ///
-/// This can be used to provide l-value/r-value overrides of member functions.
-/// The r-value override should be guarded by LLVM_HAS_RVALUE_REFERENCE_THIS
+/// This can be used to provide lvalue/rvalue overrides of member functions.
+/// The rvalue override should be guarded by LLVM_HAS_RVALUE_REFERENCE_THIS
 #if LLVM_HAS_RVALUE_REFERENCE_THIS
 #define LLVM_LVALUE_FUNCTION &
 #else
@@ -223,6 +223,16 @@
 #define LLVM_ATTRIBUTE_RETURNS_NONNULL
 #endif
 
+/// \macro LLVM_ATTRIBUTE_RETURNS_NOALIAS Used to mark a function as returning a
+/// pointer that does not alias any other valid pointer.
+#ifdef __GNUC__
+#define LLVM_ATTRIBUTE_RETURNS_NOALIAS __attribute__((__malloc__))
+#elif defined(_MSC_VER)
+#define LLVM_ATTRIBUTE_RETURNS_NOALIAS __declspec(restrict)
+#else
+#define LLVM_ATTRIBUTE_RETURNS_NOALIAS
+#endif
+
 /// LLVM_EXTENSION - Support compilers where we have a keyword to suppress
 /// pedantic diagnostics.
 #ifdef __GNUC__