llvm-project/clang
Erik Pilkington 9c3b588db9 Add a new builtin: __builtin_dynamic_object_size
This builtin has the same UI as __builtin_object_size, but has the
potential to be evaluated dynamically. It is meant to be used as a
drop-in replacement for libraries that use __builtin_object_size when
a dynamic checking mode is enabled. For instance,
__builtin_object_size fails to provide any extra checking in the
following function:

  void f(size_t alloc) {
    char* p = malloc(alloc);
    strcpy(p, "foobar"); // expands to __builtin___strcpy_chk(p, "foobar", __builtin_object_size(p, 0))
  }

This is an overflow if alloc < 7, but because LLVM can't fold the
object size intrinsic statically, it folds __builtin_object_size to
-1. With __builtin_dynamic_object_size, alloc is passed through to
__builtin___strcpy_chk.

rdar://32212419

Differential revision: https://reviews.llvm.org/D56760

llvm-svn: 352665
2019-01-30 20:34:53 +00:00
..
INPUTS
bindings Fix python3 compability issue in clang binding 2019-01-24 10:34:44 +00:00
cmake [CMake][Fuchsia] Re-enable iOS runtimes for Fuchsia standard 2019-01-30 02:06:06 +00:00
docs Add a new builtin: __builtin_dynamic_object_size 2019-01-30 20:34:53 +00:00
examples Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
include Add a new builtin: __builtin_dynamic_object_size 2019-01-30 20:34:53 +00:00
lib Add a new builtin: __builtin_dynamic_object_size 2019-01-30 20:34:53 +00:00
runtime Fix check-hwasan with LLVM_BUILD_EXTERNAL_COMPILER_RT=ON 2019-01-03 22:50:45 +00:00
test Add a new builtin: __builtin_dynamic_object_size 2019-01-30 20:34:53 +00:00
tools [clang][OpenMP] OMPFlushClause is synthetic, no such clause exists 2019-01-28 17:04:11 +00:00
unittests [clang-format] Fix line parsing for noexcept lambdas 2019-01-30 13:54:32 +00:00
utils [ASTDump] Rename methods which are conceptually Visits 2019-01-30 19:49:49 +00:00
www Adjust documentation for git migration. 2019-01-29 16:37:27 +00:00
.arcconfig
.clang-format
.clang-tidy
.gitignore Adjust documentation for git migration. 2019-01-29 16:37:27 +00:00
CMakeLists.txt inhereit LLVM_ENABLE_LIBXML2 2018-11-29 14:57:14 +00:00
CODE_OWNERS.TXT Add myself as code owner for OpenBSD driver 2018-11-30 21:42:34 +00:00
INSTALL.txt
LICENSE.TXT Fix typos throughout the license files that somehow I and my reviewers 2019-01-21 09:52:34 +00:00
ModuleInfo.txt
NOTES.txt PTH-- Remove feature entirely- 2018-12-04 14:34:09 +00:00
README.txt

README.txt

//===----------------------------------------------------------------------===//
// C Language Family Front-end
//===----------------------------------------------------------------------===//

Welcome to Clang.  This is a compiler front-end for the C family of languages
(C, C++, Objective-C, and Objective-C++) which is built as part of the LLVM
compiler infrastructure project.

Unlike many other compiler frontends, Clang is useful for a number of things
beyond just compiling code: we intend for Clang to be host to a number of
different source-level tools.  One example of this is the Clang Static Analyzer.

If you're interested in more (including how to build Clang) it is best to read
the relevant web sites.  Here are some pointers:

Information on Clang:             http://clang.llvm.org/
Building and using Clang:         http://clang.llvm.org/get_started.html
Clang Static Analyzer:            http://clang-analyzer.llvm.org/
Information on the LLVM project:  http://llvm.org/

If you have questions or comments about Clang, a great place to discuss them is
on the Clang development mailing list:
  http://lists.llvm.org/mailman/listinfo/cfe-dev

If you find a bug in Clang, please file it in the LLVM bug tracker:
  http://llvm.org/bugs/