From 4d28d3f32e7f213e300b24bc61c3f0ac9d6e1ab6 Mon Sep 17 00:00:00 2001 From: Alon Zakai Date: Thu, 19 Dec 2019 09:04:08 -0800 Subject: DWARF parsing and writing support using LLVM (#2520) This imports LLVM code for DWARF handling. That code has the Apache 2 license like us. It's also the same code used to emit DWARF in the common toolchain, so it seems like a safe choice. This adds two passes: --dwarfdump which runs the same code LLVM runs for llvm-dwarfdump. This shows we can parse it ok, and will be useful for debugging. And --dwarfupdate writes out the DWARF sections (unchanged from what we read, so it just roundtrips - for updating we need #2515). This puts LLVM in thirdparty which is added here. All the LLVM code is behind USE_LLVM_DWARF, which is on by default, but off in JS for now, as it increases code size by 20%. This current approach imports the LLVM files directly. This is not how they are intended to be used, so it required a bunch of local changes - more than I expected actually, for the platform-specific stuff. For now this seems to work, so it may be good enough, but in the long term we may want to switch to linking against libllvm. A downside to doing that is that binaryen users would need to have an LLVM build, and even in the waterfall builds we'd have a problem - while we ship LLVM there anyhow, we constantly update it, which means that binaryen would need to be on latest llvm all the time too (which otherwise, given DWARF is quite stable, we might not need to constantly update). An even larger issue is that as I did this work I learned about how DWARF works in LLVM, and while the reading code is easy to reuse, the writing code is trickier. The main code path is heavily integrated with the MC layer, which we don't have - we might want to create a "fake MC layer" for that, but it sounds hard. Instead, there is the YAML path which is used mostly for testing, and which can convert DWARF to and from YAML and from binary. Using the non-YAML parts there, we can convert binary DWARF to the YAML layer's nice Info data, then convert that to binary. This works, however, this is not the path LLVM uses normally, and it supports only some basic DWARF sections - I had to add ranges support, in fact. So if we need more complex things, we may end up needing to use the MC layer approach, or consider some other DWARF library. However, hopefully that should not affect the core binaryen code which just calls a library for DWARF stuff. Helps #2400 --- .../llvm-project/include/llvm/Support/Compiler.h | 585 +++++++++++++++++++++ 1 file changed, 585 insertions(+) create mode 100644 third_party/llvm-project/include/llvm/Support/Compiler.h (limited to 'third_party/llvm-project/include/llvm/Support/Compiler.h') diff --git a/third_party/llvm-project/include/llvm/Support/Compiler.h b/third_party/llvm-project/include/llvm/Support/Compiler.h new file mode 100644 index 000000000..cb7e57d4c --- /dev/null +++ b/third_party/llvm-project/include/llvm/Support/Compiler.h @@ -0,0 +1,585 @@ +//===-- llvm/Support/Compiler.h - Compiler abstraction support --*- C++ -*-===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// +// +// This file defines several macros, based on the current compiler. This allows +// use of compiler-specific features in a way that remains portable. This header +// can be included from either C or C++. +// +//===----------------------------------------------------------------------===// + +#ifndef LLVM_SUPPORT_COMPILER_H +#define LLVM_SUPPORT_COMPILER_H + +#include "llvm/Config/llvm-config.h" + +#ifdef __cplusplus +#include +#endif +#include + +#if defined(_MSC_VER) +#include +#endif + +#ifndef __has_feature +# define __has_feature(x) 0 +#endif + +#ifndef __has_extension +# define __has_extension(x) 0 +#endif + +#ifndef __has_attribute +# define __has_attribute(x) 0 +#endif + +#ifndef __has_builtin +# define __has_builtin(x) 0 +#endif + +// Only use __has_cpp_attribute in C++ mode. GCC defines __has_cpp_attribute in +// C mode, but the :: in __has_cpp_attribute(scoped::attribute) is invalid. +#ifndef LLVM_HAS_CPP_ATTRIBUTE +#if defined(__cplusplus) && defined(__has_cpp_attribute) +# define LLVM_HAS_CPP_ATTRIBUTE(x) __has_cpp_attribute(x) +#else +# define LLVM_HAS_CPP_ATTRIBUTE(x) 0 +#endif +#endif + +/// \macro LLVM_GNUC_PREREQ +/// Extend the default __GNUC_PREREQ even if glibc's features.h isn't +/// available. +#ifndef LLVM_GNUC_PREREQ +# if defined(__GNUC__) && defined(__GNUC_MINOR__) && defined(__GNUC_PATCHLEVEL__) +# define LLVM_GNUC_PREREQ(maj, min, patch) \ + ((__GNUC__ << 20) + (__GNUC_MINOR__ << 10) + __GNUC_PATCHLEVEL__ >= \ + ((maj) << 20) + ((min) << 10) + (patch)) +# elif defined(__GNUC__) && defined(__GNUC_MINOR__) +# define LLVM_GNUC_PREREQ(maj, min, patch) \ + ((__GNUC__ << 20) + (__GNUC_MINOR__ << 10) >= ((maj) << 20) + ((min) << 10)) +# else +# define LLVM_GNUC_PREREQ(maj, min, patch) 0 +# endif +#endif + +/// \macro LLVM_MSC_PREREQ +/// Is the compiler MSVC of at least the specified version? +/// The common \param version values to check for are: +/// * 1910: VS2017, version 15.1 & 15.2 +/// * 1911: VS2017, version 15.3 & 15.4 +/// * 1912: VS2017, version 15.5 +/// * 1913: VS2017, version 15.6 +/// * 1914: VS2017, version 15.7 +/// * 1915: VS2017, version 15.8 +/// * 1916: VS2017, version 15.9 +/// * 1920: VS2019, version 16.0 +/// * 1921: VS2019, version 16.1 +#ifdef _MSC_VER +#define LLVM_MSC_PREREQ(version) (_MSC_VER >= (version)) + +// We require at least MSVC 2017. +#if !LLVM_MSC_PREREQ(1910) +#error LLVM requires at least MSVC 2017. +#endif + +#else +#define LLVM_MSC_PREREQ(version) 0 +#endif + +/// Does the compiler support ref-qualifiers for *this? +/// +/// 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 ref-qualifiers for *this are supported. +/// +/// 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 +#define LLVM_LVALUE_FUNCTION +#endif + +/// LLVM_LIBRARY_VISIBILITY - If a class marked with this attribute is linked +/// into a shared library, then the class should be private to the library and +/// not accessible from outside it. Can also be used to mark variables and +/// functions, making them private to any shared library they are linked into. +/// On PE/COFF targets, library visibility is the default, so this isn't needed. +#if (__has_attribute(visibility) || LLVM_GNUC_PREREQ(4, 0, 0)) && \ + !defined(__MINGW32__) && !defined(__CYGWIN__) && !defined(_WIN32) +#define LLVM_LIBRARY_VISIBILITY __attribute__ ((visibility("hidden"))) +#else +#define LLVM_LIBRARY_VISIBILITY +#endif + +#if defined(__GNUC__) +#define LLVM_PREFETCH(addr, rw, locality) __builtin_prefetch(addr, rw, locality) +#else +#define LLVM_PREFETCH(addr, rw, locality) +#endif + +#if __has_attribute(used) || LLVM_GNUC_PREREQ(3, 1, 0) +#define LLVM_ATTRIBUTE_USED __attribute__((__used__)) +#else +#define LLVM_ATTRIBUTE_USED +#endif + +/// LLVM_NODISCARD - Warn if a type or return value is discarded. + +// Use the 'nodiscard' attribute in C++17 or newer mode. +#if __cplusplus > 201402L && LLVM_HAS_CPP_ATTRIBUTE(nodiscard) +#define LLVM_NODISCARD [[nodiscard]] +#elif LLVM_HAS_CPP_ATTRIBUTE(clang::warn_unused_result) +#define LLVM_NODISCARD [[clang::warn_unused_result]] +// Clang in C++14 mode claims that it has the 'nodiscard' attribute, but also +// warns in the pedantic mode that 'nodiscard' is a C++17 extension (PR33518). +// Use the 'nodiscard' attribute in C++14 mode only with GCC. +// TODO: remove this workaround when PR33518 is resolved. +#elif defined(__GNUC__) && LLVM_HAS_CPP_ATTRIBUTE(nodiscard) +#define LLVM_NODISCARD [[nodiscard]] +#else +#define LLVM_NODISCARD +#endif + +// Indicate that a non-static, non-const C++ member function reinitializes +// the entire object to a known state, independent of the previous state of +// the object. +// +// The clang-tidy check bugprone-use-after-move recognizes this attribute as a +// marker that a moved-from object has left the indeterminate state and can be +// reused. +#if LLVM_HAS_CPP_ATTRIBUTE(clang::reinitializes) +#define LLVM_ATTRIBUTE_REINITIALIZES [[clang::reinitializes]] +#else +#define LLVM_ATTRIBUTE_REINITIALIZES +#endif + +// Some compilers warn about unused functions. When a function is sometimes +// used or not depending on build settings (e.g. a function only called from +// within "assert"), this attribute can be used to suppress such warnings. +// +// However, it shouldn't be used for unused *variables*, as those have a much +// more portable solution: +// (void)unused_var_name; +// Prefer cast-to-void wherever it is sufficient. +#if __has_attribute(unused) || LLVM_GNUC_PREREQ(3, 1, 0) +#define LLVM_ATTRIBUTE_UNUSED __attribute__((__unused__)) +#else +#define LLVM_ATTRIBUTE_UNUSED +#endif + +// FIXME: Provide this for PE/COFF targets. +#if (__has_attribute(weak) || LLVM_GNUC_PREREQ(4, 0, 0)) && \ + (!defined(__MINGW32__) && !defined(__CYGWIN__) && !defined(_WIN32)) +#define LLVM_ATTRIBUTE_WEAK __attribute__((__weak__)) +#else +#define LLVM_ATTRIBUTE_WEAK +#endif + +// Prior to clang 3.2, clang did not accept any spelling of +// __has_attribute(const), so assume it is supported. +#if defined(__clang__) || defined(__GNUC__) +// aka 'CONST' but following LLVM Conventions. +#define LLVM_READNONE __attribute__((__const__)) +#else +#define LLVM_READNONE +#endif + +#if __has_attribute(pure) || defined(__GNUC__) +// aka 'PURE' but following LLVM Conventions. +#define LLVM_READONLY __attribute__((__pure__)) +#else +#define LLVM_READONLY +#endif + +#if __has_builtin(__builtin_expect) || LLVM_GNUC_PREREQ(4, 0, 0) +#define LLVM_LIKELY(EXPR) __builtin_expect((bool)(EXPR), true) +#define LLVM_UNLIKELY(EXPR) __builtin_expect((bool)(EXPR), false) +#else +#define LLVM_LIKELY(EXPR) (EXPR) +#define LLVM_UNLIKELY(EXPR) (EXPR) +#endif + +/// LLVM_ATTRIBUTE_NOINLINE - On compilers where we have a directive to do so, +/// mark a method "not for inlining". +#if __has_attribute(noinline) || LLVM_GNUC_PREREQ(3, 4, 0) +#define LLVM_ATTRIBUTE_NOINLINE __attribute__((noinline)) +#elif defined(_MSC_VER) +#define LLVM_ATTRIBUTE_NOINLINE __declspec(noinline) +#else +#define LLVM_ATTRIBUTE_NOINLINE +#endif + +/// LLVM_ATTRIBUTE_ALWAYS_INLINE - On compilers where we have a directive to do +/// so, mark a method "always inline" because it is performance sensitive. GCC +/// 3.4 supported this but is buggy in various cases and produces unimplemented +/// errors, just use it in GCC 4.0 and later. +#if __has_attribute(always_inline) || LLVM_GNUC_PREREQ(4, 0, 0) +#define LLVM_ATTRIBUTE_ALWAYS_INLINE __attribute__((always_inline)) +#elif defined(_MSC_VER) +#define LLVM_ATTRIBUTE_ALWAYS_INLINE __forceinline +#else +#define LLVM_ATTRIBUTE_ALWAYS_INLINE +#endif + +#ifdef __GNUC__ +#define LLVM_ATTRIBUTE_NORETURN __attribute__((noreturn)) +#elif defined(_MSC_VER) +#define LLVM_ATTRIBUTE_NORETURN __declspec(noreturn) +#else +#define LLVM_ATTRIBUTE_NORETURN +#endif + +#if __has_attribute(returns_nonnull) || LLVM_GNUC_PREREQ(4, 9, 0) +#define LLVM_ATTRIBUTE_RETURNS_NONNULL __attribute__((returns_nonnull)) +#elif defined(_MSC_VER) +#define LLVM_ATTRIBUTE_RETURNS_NONNULL _Ret_notnull_ +#else +#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_FALLTHROUGH - Mark fallthrough cases in switch statements. +#if __cplusplus > 201402L && LLVM_HAS_CPP_ATTRIBUTE(fallthrough) +#define LLVM_FALLTHROUGH [[fallthrough]] +#elif LLVM_HAS_CPP_ATTRIBUTE(gnu::fallthrough) +#define LLVM_FALLTHROUGH [[gnu::fallthrough]] +#elif __has_attribute(fallthrough) +#define LLVM_FALLTHROUGH __attribute__((fallthrough)) +#elif LLVM_HAS_CPP_ATTRIBUTE(clang::fallthrough) +#define LLVM_FALLTHROUGH [[clang::fallthrough]] +#else +#define LLVM_FALLTHROUGH +#endif + +/// LLVM_REQUIRE_CONSTANT_INITIALIZATION - Apply this to globals to ensure that +/// they are constant initialized. +#if LLVM_HAS_CPP_ATTRIBUTE(clang::require_constant_initialization) +#define LLVM_REQUIRE_CONSTANT_INITIALIZATION \ + [[clang::require_constant_initialization]] +#else +#define LLVM_REQUIRE_CONSTANT_INITIALIZATION +#endif + +/// LLVM_EXTENSION - Support compilers where we have a keyword to suppress +/// pedantic diagnostics. +#ifdef __GNUC__ +#define LLVM_EXTENSION __extension__ +#else +#define LLVM_EXTENSION +#endif + +// LLVM_ATTRIBUTE_DEPRECATED(decl, "message") +#if __has_feature(attribute_deprecated_with_message) +# define LLVM_ATTRIBUTE_DEPRECATED(decl, message) \ + decl __attribute__((deprecated(message))) +#elif defined(__GNUC__) +# define LLVM_ATTRIBUTE_DEPRECATED(decl, message) \ + decl __attribute__((deprecated)) +#elif defined(_MSC_VER) +# define LLVM_ATTRIBUTE_DEPRECATED(decl, message) \ + __declspec(deprecated(message)) decl +#else +# define LLVM_ATTRIBUTE_DEPRECATED(decl, message) \ + decl +#endif + +/// LLVM_BUILTIN_UNREACHABLE - On compilers which support it, expands +/// to an expression which states that it is undefined behavior for the +/// compiler to reach this point. Otherwise is not defined. +#if __has_builtin(__builtin_unreachable) || LLVM_GNUC_PREREQ(4, 5, 0) +# define LLVM_BUILTIN_UNREACHABLE __builtin_unreachable() +#elif defined(_MSC_VER) +# define LLVM_BUILTIN_UNREACHABLE __assume(false) +#endif + +/// LLVM_BUILTIN_TRAP - On compilers which support it, expands to an expression +/// which causes the program to exit abnormally. +#if __has_builtin(__builtin_trap) || LLVM_GNUC_PREREQ(4, 3, 0) +# define LLVM_BUILTIN_TRAP __builtin_trap() +#elif defined(_MSC_VER) +// The __debugbreak intrinsic is supported by MSVC, does not require forward +// declarations involving platform-specific typedefs (unlike RaiseException), +// results in a call to vectored exception handlers, and encodes to a short +// instruction that still causes the trapping behavior we want. +# define LLVM_BUILTIN_TRAP __debugbreak() +#else +# define LLVM_BUILTIN_TRAP *(volatile int*)0x11 = 0 +#endif + +/// LLVM_BUILTIN_DEBUGTRAP - On compilers which support it, expands to +/// an expression which causes the program to break while running +/// under a debugger. +#if __has_builtin(__builtin_debugtrap) +# define LLVM_BUILTIN_DEBUGTRAP __builtin_debugtrap() +#elif defined(_MSC_VER) +// The __debugbreak intrinsic is supported by MSVC and breaks while +// running under the debugger, and also supports invoking a debugger +// when the OS is configured appropriately. +# define LLVM_BUILTIN_DEBUGTRAP __debugbreak() +#else +// Just continue execution when built with compilers that have no +// support. This is a debugging aid and not intended to force the +// program to abort if encountered. +# define LLVM_BUILTIN_DEBUGTRAP +#endif + +/// \macro LLVM_ASSUME_ALIGNED +/// Returns a pointer with an assumed alignment. +#if __has_builtin(__builtin_assume_aligned) || LLVM_GNUC_PREREQ(4, 7, 0) +# define LLVM_ASSUME_ALIGNED(p, a) __builtin_assume_aligned(p, a) +#elif defined(LLVM_BUILTIN_UNREACHABLE) +// As of today, clang does not support __builtin_assume_aligned. +# define LLVM_ASSUME_ALIGNED(p, a) \ + (((uintptr_t(p) % (a)) == 0) ? (p) : (LLVM_BUILTIN_UNREACHABLE, (p))) +#else +# define LLVM_ASSUME_ALIGNED(p, a) (p) +#endif + +/// \macro LLVM_PACKED +/// Used to specify a packed structure. +/// LLVM_PACKED( +/// struct A { +/// int i; +/// int j; +/// int k; +/// long long l; +/// }); +/// +/// LLVM_PACKED_START +/// struct B { +/// int i; +/// int j; +/// int k; +/// long long l; +/// }; +/// LLVM_PACKED_END +#ifdef _MSC_VER +# define LLVM_PACKED(d) __pragma(pack(push, 1)) d __pragma(pack(pop)) +# define LLVM_PACKED_START __pragma(pack(push, 1)) +# define LLVM_PACKED_END __pragma(pack(pop)) +#else +# define LLVM_PACKED(d) d __attribute__((packed)) +# define LLVM_PACKED_START _Pragma("pack(push, 1)") +# define LLVM_PACKED_END _Pragma("pack(pop)") +#endif + +/// \macro LLVM_PTR_SIZE +/// A constant integer equivalent to the value of sizeof(void*). +/// Generally used in combination with alignas or when doing computation in the +/// preprocessor. +#ifdef __SIZEOF_POINTER__ +# define LLVM_PTR_SIZE __SIZEOF_POINTER__ +#elif defined(_WIN64) +# define LLVM_PTR_SIZE 8 +#elif defined(_WIN32) +# define LLVM_PTR_SIZE 4 +#elif defined(_MSC_VER) +# error "could not determine LLVM_PTR_SIZE as a constant int for MSVC" +#else +# define LLVM_PTR_SIZE sizeof(void *) +#endif + +/// \macro LLVM_MEMORY_SANITIZER_BUILD +/// Whether LLVM itself is built with MemorySanitizer instrumentation. +#if __has_feature(memory_sanitizer) +# define LLVM_MEMORY_SANITIZER_BUILD 1 +# include +#else +# define LLVM_MEMORY_SANITIZER_BUILD 0 +# define __msan_allocated_memory(p, size) +# define __msan_unpoison(p, size) +#endif + +/// \macro LLVM_ADDRESS_SANITIZER_BUILD +/// Whether LLVM itself is built with AddressSanitizer instrumentation. +#if __has_feature(address_sanitizer) || defined(__SANITIZE_ADDRESS__) +# define LLVM_ADDRESS_SANITIZER_BUILD 1 +# include +#else +# define LLVM_ADDRESS_SANITIZER_BUILD 0 +# define __asan_poison_memory_region(p, size) +# define __asan_unpoison_memory_region(p, size) +#endif + +/// \macro LLVM_THREAD_SANITIZER_BUILD +/// Whether LLVM itself is built with ThreadSanitizer instrumentation. +#if __has_feature(thread_sanitizer) || defined(__SANITIZE_THREAD__) +# define LLVM_THREAD_SANITIZER_BUILD 1 +#else +# define LLVM_THREAD_SANITIZER_BUILD 0 +#endif + +#if LLVM_THREAD_SANITIZER_BUILD +// Thread Sanitizer is a tool that finds races in code. +// See http://code.google.com/p/data-race-test/wiki/DynamicAnnotations . +// tsan detects these exact functions by name. +#ifdef __cplusplus +extern "C" { +#endif +void AnnotateHappensAfter(const char *file, int line, const volatile void *cv); +void AnnotateHappensBefore(const char *file, int line, const volatile void *cv); +void AnnotateIgnoreWritesBegin(const char *file, int line); +void AnnotateIgnoreWritesEnd(const char *file, int line); +#ifdef __cplusplus +} +#endif + +// This marker is used to define a happens-before arc. The race detector will +// infer an arc from the begin to the end when they share the same pointer +// argument. +# define TsanHappensBefore(cv) AnnotateHappensBefore(__FILE__, __LINE__, cv) + +// This marker defines the destination of a happens-before arc. +# define TsanHappensAfter(cv) AnnotateHappensAfter(__FILE__, __LINE__, cv) + +// Ignore any races on writes between here and the next TsanIgnoreWritesEnd. +# define TsanIgnoreWritesBegin() AnnotateIgnoreWritesBegin(__FILE__, __LINE__) + +// Resume checking for racy writes. +# define TsanIgnoreWritesEnd() AnnotateIgnoreWritesEnd(__FILE__, __LINE__) +#else +# define TsanHappensBefore(cv) +# define TsanHappensAfter(cv) +# define TsanIgnoreWritesBegin() +# define TsanIgnoreWritesEnd() +#endif + +/// \macro LLVM_NO_SANITIZE +/// Disable a particular sanitizer for a function. +#if __has_attribute(no_sanitize) +#define LLVM_NO_SANITIZE(KIND) __attribute__((no_sanitize(KIND))) +#else +#define LLVM_NO_SANITIZE(KIND) +#endif + +/// Mark debug helper function definitions like dump() that should not be +/// stripped from debug builds. +/// Note that you should also surround dump() functions with +/// `#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)` so they do always +/// get stripped in release builds. +// FIXME: Move this to a private config.h as it's not usable in public headers. +#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) +#define LLVM_DUMP_METHOD LLVM_ATTRIBUTE_NOINLINE LLVM_ATTRIBUTE_USED +#else +#define LLVM_DUMP_METHOD LLVM_ATTRIBUTE_NOINLINE +#endif + +/// \macro LLVM_PRETTY_FUNCTION +/// Gets a user-friendly looking function signature for the current scope +/// using the best available method on each platform. The exact format of the +/// resulting string is implementation specific and non-portable, so this should +/// only be used, for example, for logging or diagnostics. +#if defined(_MSC_VER) +#define LLVM_PRETTY_FUNCTION __FUNCSIG__ +#elif defined(__GNUC__) || defined(__clang__) +#define LLVM_PRETTY_FUNCTION __PRETTY_FUNCTION__ +#else +#define LLVM_PRETTY_FUNCTION __func__ +#endif + +/// \macro LLVM_THREAD_LOCAL +/// A thread-local storage specifier which can be used with globals, +/// extern globals, and static globals. +/// +/// This is essentially an extremely restricted analog to C++11's thread_local +/// support, and uses that when available. However, it falls back on +/// platform-specific or vendor-provided extensions when necessary. These +/// extensions don't support many of the C++11 thread_local's features. You +/// should only use this for PODs that you can statically initialize to +/// some constant value. In almost all circumstances this is most appropriate +/// for use with a pointer, integer, or small aggregation of pointers and +/// integers. +#if LLVM_ENABLE_THREADS +#if __has_feature(cxx_thread_local) +#define LLVM_THREAD_LOCAL thread_local +#elif defined(_MSC_VER) +// MSVC supports this with a __declspec. +#define LLVM_THREAD_LOCAL __declspec(thread) +#else +// Clang, GCC, and other compatible compilers used __thread prior to C++11 and +// we only need the restricted functionality that provides. +#define LLVM_THREAD_LOCAL __thread +#endif +#else // !LLVM_ENABLE_THREADS +// If threading is disabled entirely, this compiles to nothing and you get +// a normal global variable. +#define LLVM_THREAD_LOCAL +#endif + +/// \macro LLVM_ENABLE_EXCEPTIONS +/// Whether LLVM is built with exception support. +#if __has_feature(cxx_exceptions) +#define LLVM_ENABLE_EXCEPTIONS 1 +#elif defined(__GNUC__) && defined(__EXCEPTIONS) +#define LLVM_ENABLE_EXCEPTIONS 1 +#elif defined(_MSC_VER) && defined(_CPPUNWIND) +#define LLVM_ENABLE_EXCEPTIONS 1 +#endif + +#ifdef __cplusplus +namespace llvm { + +/// Allocate a buffer of memory with the given size and alignment. +/// +/// When the compiler supports aligned operator new, this will use it to to +/// handle even over-aligned allocations. +/// +/// However, this doesn't make any attempt to leverage the fancier techniques +/// like posix_memalign due to portability. It is mostly intended to allow +/// compatibility with platforms that, after aligned allocation was added, use +/// reduced default alignment. +inline void *allocate_buffer(size_t Size, size_t Alignment) { + return ::operator new(Size +#ifdef __cpp_aligned_new + , + std::align_val_t(Alignment) +#endif + ); +} + +/// Deallocate a buffer of memory with the given size and alignment. +/// +/// If supported, this will used the sized delete operator. Also if supported, +/// this will pass the alignment to the delete operator. +/// +/// The pointer must have been allocated with the corresponding new operator, +/// most likely using the above helper. +inline void deallocate_buffer(void *Ptr, size_t Size, size_t Alignment) { + ::operator delete(Ptr +#ifdef __cpp_sized_deallocation + , + Size +#endif +#ifdef __cpp_aligned_new + , + std::align_val_t(Alignment) +#endif + ); +} + +} // End namespace llvm + +#endif // __cplusplus +#endif -- cgit v1.2.3