From ff0c0d8ab3e316bb6e2741fedb3b545e198eab7a Mon Sep 17 00:00:00 2001 From: Hans Wennborg Date: Fri, 2 Mar 2018 09:50:00 +0000 Subject: ReleaseNotes: move the retpoline bullets higher git-svn-id: https://llvm.org/svn/llvm-project/cfe/branches/release_60@326550 91177308-0d34-0410-b5e6-96231b3b80d8 --- docs/ReleaseNotes.rst | 36 ++++++++++++++++++------------------ 1 file changed, 18 insertions(+), 18 deletions(-) diff --git a/docs/ReleaseNotes.rst b/docs/ReleaseNotes.rst index 5ceb1a4b51..d817907e22 100644 --- a/docs/ReleaseNotes.rst +++ b/docs/ReleaseNotes.rst @@ -35,6 +35,12 @@ sections with improvements to Clang's support for those languages. Non-comprehensive list of changes in this release ------------------------------------------------- +- Support for `retpolines `_ + was added to help mitigate "branch target injection" (variant #2) of the + "Spectre" speculative side channels described by `Project Zero + `_ + and the `Spectre paper `_. + - Bitrig OS was merged back into OpenBSD, so Bitrig support has been removed from Clang/LLVM. @@ -51,12 +57,6 @@ Non-comprehensive list of changes in this release ``__is_target_vendor``, ``__is_target_os``, and ``__is_target_environment`` can be used to to examine the individual components of the target triple. -- Support for `retpolines `_ - was added to help mitigate "branch target injection" (variant #2) of the - "Spectre" speculative side channels described by `Project Zero - `_ - and the `Spectre paper `_. - Improvements to Clang's diagnostics ----------------------------------- @@ -115,6 +115,18 @@ Improvements to Clang's diagnostics New Compiler Flags ------------------ +- Clang supports the ``-mretpoline`` flag to enable `retpolines + `_. Code compiled with this + flag will be hardened against variant #2 of the Spectre attack. Indirect + branches from switches or gotos removed from the code, and indirect calls + will be made through a "retpoline" thunk. The necessary thunks will + automatically be inserted into the generated code. Clang also supports + ``-mretpoline-external-thunk`` which works like ``-mretpoline`` but requires + the user to provide their own thunk definitions. The external thunk names + start with ``__x86_indirect_thunk_`` and end in a register name. For 64-bit + platforms, only an ``r11`` thunk is used, but for 32-bit platforms ``eax``, + ``ecx``, ``edx``, and ``edi`` thunks are used. + - Clang now supports configuration files. These are collections of driver options, which can be applied by specifying the configuration file, either using command line option ``--config foo.cfg`` or encoding it into executable @@ -144,18 +156,6 @@ New Compiler Flags - New ``-nostdlib++`` flag to disable linking the C++ standard library. Similar to using ``clang`` instead of ``clang++`` but doesn't disable ``-lm``. -- Clang supports the ``-mretpoline`` flag to enable `retpolines - `_. Code compiled with this - flag will be hardened against variant #2 of the Spectre attack. Indirect - branches from switches or gotos removed from the code, and indirect calls - will be made through a "retpoline" thunk. The necessary thunks will - automatically be inserted into the generated code. Clang also supports - ``-mretpoline-external-thunk`` which works like ``-mretpoline`` but requires - the user to provide their own thunk definitions. The external thunk names - start with ``__x86_indirect_thunk_`` and end in a register name. For 64-bit - platforms, only an ``r11`` thunk is used, but for 32-bit platforms ``eax``, - ``ecx``, ``edx``, and ``edi`` thunks are used. - Attribute Changes in Clang -------------------------- -- cgit v1.2.3