Commit Graph

6207 Commits

Author SHA1 Message Date
Kevin Athey e0b469ffa1 [clang-cl][sanitizer] Add -fsanitize-address-use-after-return to clang.
Also:
  - add driver test (fsanitize-use-after-return.c)
  - add basic IR test (asan-use-after-return.cpp)
  - (NFC) cleaned up logic for generating table of __asan_stack_malloc
    depending on flag.

for issue: https://github.com/google/sanitizers/issues/1394

Reviewed By: vitalybuka

Differential Revision: https://reviews.llvm.org/D104076
2021-06-11 12:07:35 -07:00
Aaron En Ye Shi f2cc0427b1 [HIP] Fix --hip-version flag with 0 as component
Allow the usage of minor version 0, for hip versions
such as 4.0. Change the default values when performing
version checks.

Reviewed By: yaxunl

Differential Revision: https://reviews.llvm.org/D104062
2021-06-11 16:25:03 +00:00
Matt Morehouse 0867edfc64 [HWASan] Add basic stack tagging support for LAM.
Adds the basic instrumentation needed for stack tagging.

Currently does not support stack short granules or TLS stack histories,
since a different code path is followed for the callback instrumentation
we use.

We may simply wait to support these two features until we switch to
a custom calling convention.

Patch By: xiangzhangllvm, morehouse

Reviewed By: vitalybuka

Differential Revision: https://reviews.llvm.org/D102901
2021-06-11 08:21:17 -07:00
Petr Hosek 22f194909a Revert "[Driver] Support libc++ in MSVC"
This reverts commit 9625d61eb6 since
libc++ currently has issues with disabled exceptions which breaks
the runtimes build.
2021-06-11 00:45:56 -07:00
Nick Desaulniers fc018ebb60 [IR] make -warn-frame-size into a module attr
-Wframe-larger-than= is an interesting warning; we can't know the frame
size until PrologueEpilogueInsertion (PEI); very late in the compilation
pipeline.

-Wframe-larger-than= was propagated through CC1 as an -mllvm flag, then
was a cl::opt in LLVM's PEI pass; this meant it was dropped during LTO
and needed to be re-specified via -plugin-opt.

Instead, make it part of the IR proper as a module level attribute,
similar to D103048. Introduce -fwarn-stack-size CC1 option.

Reviewed By: rsmith, qcolombet

Differential Revision: https://reviews.llvm.org/D103928
2021-06-10 16:15:27 -07:00
Melanie Blower c3cc14f87f Revert "[clang][FPEnv] Clang floatng point model ffp-model=precise enables ffp-contract=on"
This reverts commit 8daac37140.
The build bots are showing some fails on broadwell and arm.
Fix to LNT test suite needs work.
2021-06-10 12:19:02 -04:00
Markus Böck c70b0e808d [clang-cl] Add /permissive and /permissive-
This patch adds the command line options /permissive and /permissive- to clang-cl. These flags are used in MSVC to enable various /Zc language conformance options at once. In particular, /permissive is used to enable the various non standard behaviour of MSVC, while /permissive- is the opposite.

When either of two command lines are specified they are simply expanded to the various underlying /Zc options. In particular when /permissive is passed it currently expands to:

/Zc:twoPhase- (disable two phase lookup)
-fno-operator-names (disable C++ operator keywords)
/permissive- expands to the opposites of these flags + /Zc:strictStrings (/Zc:strictStrings- does not currently exist). In the future, if any more MSVC workarounds are ever added they can easily be added to the expansion. One is also able to override settings done by permissive. Specifying /permissive- /Zc:twoPhase- will apply the settings from permissive minus, but disables two phase lookup.

Motivation for this patch was mainly parity with MSVC as well as compatibility with Windows SDK headers. The /permissive page from MSVC documents various workarounds that have to be done for the Windows SDK headers [1], when MSVC is used with /permissive-. In these, Microsoft often recommends simply compiling with /permissive for the specified source files. Since some of these also apply to clang-cl (which acts like /permissive- by default mostly), and some are currently implemented as "hacks" within clang that I'd like to remove, adding /permissive and /permissive- to be in full parity with MSVC and Microsofts documentation made sense to me.

[1] https://docs.microsoft.com/en-us/cpp/build/reference/permissive-standards-conformance?view=msvc-160#windows-header-issues

Differential Revision: https://reviews.llvm.org/D103773
2021-06-10 17:06:19 +02:00
Markus Böck 936d6756cc [clang][msvc] Define _HAS_STATIC_RTTI to 0, when compiling with -fno-rtti
When using the -fno-rtti option of the GCC style clang++, using typeid results in an error. The MSVC STL however kindly provides a define flag called _HAS_STATIC_RTTI, which either enables or disables uses of typeid throughout the STL. By default, if undefined, it is set to 1, enabling the use of typeid.

With this patch, _HAS_STATIC_RTTI is set to 0 when -fno-rtti is specified. This way various headers of the MSVC STL like functional can be consumed without compilation failures.

Differential Revision: https://reviews.llvm.org/D103771
2021-06-10 17:02:44 +02:00
Markus Böck 9833b57981 [clang][driver] Add -foperator-names
This patch adds the command line option -foperator-names which acts as the opposite of -fno-operator-names. With this command line option it is possible to reenable C++ operator keywords on the command line if -fno-operator-names had previously been passed.

Differential Revision: https://reviews.llvm.org/D103749
2021-06-10 17:01:35 +02:00
Melanie Blower 8daac37140 [clang][FPEnv] Clang floatng point model ffp-model=precise enables ffp-contract=on
This patch changes the ffp-model=precise to enables -ffp-contract=on
(previously -ffp-model=precise enabled -ffp-contract=fast). This is a
follow-up to Andy Kaylor's comments in the llvm-dev discussion
"Floating Point semantic modes". From the same email thread, I put
Andy's distillation of floating point options and floating point modes
into UsersManual.rst

Differential Revision: https://reviews.llvm.org/D74436
2021-06-10 09:30:41 -04:00
Yaxun (Sam) Liu 5fc2673fbc [HIP] Add --gpu-bundle-output
Added --gpu-bundle-output to control bundling/unbundling output of HIP device compilation.

By default preprocessor expansion, llvm bitcode and assembly are unbundled, code objects are
bundled.

Reviewed by: Artem Belevich, Jan Svoboda

Differential Revision: https://reviews.llvm.org/D101630
2021-06-09 23:31:43 -04:00
Keith Smiley 1c7f3395b8 clang/darwin: use response files with ld64
This crasher was fixed with Xcode 13.0 beta 1 / ld64 705. This is an
updated revert of https://reviews.llvm.org/D92357

Differential Revision: https://reviews.llvm.org/D103934
2021-06-09 09:04:37 -07:00
Petr Hosek 9625d61eb6 [Driver] Support libc++ in MSVC
This implements support for using libc++ headers and library in the MSVC
toolchain.  We only support libc++ that is a part of the toolchain, and
not headers installed elsewhere on the system.

Differential Revision: https://reviews.llvm.org/D101479
2021-06-07 23:36:10 -07:00
Jian Cai 9145a3d4ab Revert "[AArch64] handle -Wa,-march="
This reverts commit fd11a26d36.
2021-06-07 14:31:07 -07:00
Harald van Dijk 75521bd9d8
[X32] Add Triple::isX32(), use it.
So far, support for x86_64-linux-gnux32 has been handled by explicit
comparisons of Triple.getEnvironment() to GNUX32. This worked as long as
x86_64-linux-gnux32 was the only X32 environment to worry about, but we
now have x86_64-linux-muslx32 as well. To support this, this change adds
an isX32() function and uses it. It replaces all checks for GNUX32 or
MuslX32 by isX32(), except for the following:

- Triple::isGNUEnvironment() and Triple::isMusl() are supposed to treat
  GNUX32 and MuslX32 differently.
- computeTargetTriple() needs to be able to transform triples to add or
  remove X32 from the environment and needs to map GNU to GNUX32, and
  Musl to MuslX32.
- getMultiarchTriple() completely lacks any Musl support and retains the
  explicit check for GNUX32 as it can only return x86_64-linux-gnux32.

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D103777
2021-06-07 20:48:39 +01:00
Jian Cai fd11a26d36 [AArch64] handle -Wa,-march=
This fixed PR#48894 for AArch64. The issue has been fixed for Arm in
https://reviews.llvm.org/D95872

The following rules apply to -Wa,-march with this change:
  - Only compiler options apply to non assembly files
  - Compiler and assembler options apply to assembly files
  - For assembly files, we prefer the assembler option(s) if we have both kinds of option
  - Of the options that apply (or are preferred), the last value wins (it's not additive)

Reviewed By: DavidSpickett, nickdesaulniers

Differential Revision: https://reviews.llvm.org/D103184
2021-06-07 10:15:53 -07:00
Ten Tzen 33ba8bd2c9 [Windows SEH]: Fix -O2 crash for Windows -EHa
This patch fixes a Windows -EHa crash induced by previous commit 797ad70152.
The crash was caused by "LifetimeMarker" scope (with option -O2) that should not be considered as SEH Scope.

This change also turns off -fasync-exceptions by default under -EHa option for now.

Differential Revision: https://reviews.llvm.org/D103664#2799944
2021-06-04 14:07:44 -07:00
Yaxun (Sam) Liu b5dea8701b [HIP] Fix spack HIP device lib detection
spack HIP device library is installed at amdgcn directory under llvm/clang
directory.

This patch fixes detection of HIP device library for spack.

Reviewed by: Artem Belevich, Harmen Stoppels

Differential Revision: https://reviews.llvm.org/D103281
2021-06-04 09:12:41 -04:00
Teresa Johnson d0ee8b64ec [LTO] Fix -fwhole-program-vtables handling after HIP ThinLTO patch
A recent change (D99683) to support ThinLTO for HIP caused a regression
when compiling cuda code with -flto=thin -fwhole-program-vtables.
Specifically, we now get an error:
error: invalid argument '-fwhole-program-vtables' only allowed with '-flto'

This error is coming from the device offload cc1 action being set up for
the cuda compile, for which -flto=thin doesn't apply and gets dropped.
This is a regression, but points to a potential issue that was silently
occurring before the patch, details below.

Before D99683, the check for fwhole-program-vtables in the driver looked
like:

  if (WholeProgramVTables) {
    if (!D.isUsingLTO())
      D.Diag(diag::err_drv_argument_only_allowed_with)
          << "-fwhole-program-vtables"
          << "-flto";
    CmdArgs.push_back("-fwhole-program-vtables");
  }

And D.isUsingLTO() returned true since we have -flto=thin. However,
because the cuda cc1 compile is doing device offloading, which didn't
support any LTO, there was other code that suppressed -flto* options
from being passed to the cc1 invocation. So the cc1 invocation silently
had -fwhole-program-vtables without any -flto*. This seems potentially
problematic, since if we had any virtual calls we would get type test
assume sequences without the corresponding LTO pass that handles them.

However, with the patch, which adds support for device offloading LTO
option -foffload-lto=thin, the code has changed so that we set a bool
IsUsingLTO based on either -flto* or -foffload-lto*, depending on
whether this is the device offloading action. For the device offload
action in our compile, since we don't have -foffload-lto, IsUsingLTO is
false, and the check for LTO with -fwhole-program-vtables now fails.

What we should do is only pass through -fwhole-program-vtables to the
cc1 invocation that has LTO enabled (either the device offload action
with -foffload-lto, or the non-device offload action with -flto), and
otherwise drop the -fwhole-program-vtables for the non-LTO action.
Then we should error only if we have -fwhole-program-vtables without any
-f*lto* options.

Differential Revision: https://reviews.llvm.org/D103579
2021-06-03 14:25:03 -07:00
Chris Bieneman 13a9b2220f Don't delete the module you're inspecting
Prior to this patch when you used `clang -module-file-info` clang would
delete the module on completion because the module was treated as an
output file.

This fixes the issue so you don't need to invoke cc1 directly to get
module file information.

Reviewed By: steven_wu, phosek

Differential Revision: https://reviews.llvm.org/D103547
2021-06-03 13:00:09 -05:00
Yi Kong dcd7664f92 Add -fno-visibility-inlines-hidden option
This allows overriding -fvisibility-inlines-hidden.

Differential Revision: https://reviews.llvm.org/D103537
2021-06-03 17:07:53 +08:00
Leonard Chan e6f88dc01a [clang][Fuchsia] Turn on relative-vtables by default for Fuchsia
All fuchsia targets will now use the relative-vtables ABI by default.
Also remove -fexperimental-relative-c++-abi-vtables from test RUNs targeting fuchsia.

Differential Revision: https://reviews.llvm.org/D102374
2021-06-01 15:46:09 -07:00
Ben Shi c1ee4fb5af [clang][AVR] Add avr-libc/include to clang system include paths
Reviewed By: dylanmckay

Differential Revision: https://reviews.llvm.org/D97669
2021-05-30 22:39:07 +08:00
Martin Storsjö f59cd8a4a6 [clang] [MinGW] Fix gcc version detection/picking
Actually compare each version to the version of the last chosen one.

There's no guarantee that the added test case does showcase the
previous issue (it depends on the order that directory entries
are returned when iterating), but with the issue fixed it should behave
deterministically in any case.

Also improve the match patterns in the mingw-sysroot.cpp test a bit.

Differential Revision: https://reviews.llvm.org/D102873
2021-05-28 11:44:20 +03:00
Zequan Wu 59b8afe502 [clang-cl] Bump default -fms-compatibility-version to 19.14
MSVC required version is 19.14 now (https://reviews.llvm.org/D92515). Update the
default -fms-compatibility-version to 19.14.

Differential Revision: https://reviews.llvm.org/D103293
2021-05-27 20:40:37 -07:00
Yaxun (Sam) Liu 6d2c095020 [HIP] Check compatibility of -fgpu-sanitize with offload arch
-fgpu-sanitize is incompatible with offload arch containing xnack-.

This patch checks that.

Reviewed by: Artem Belevich

Differential Revision: https://reviews.llvm.org/D102975
2021-05-27 12:06:42 -04:00
jasonliu 7922ff6010 [AIX] Add -lc++abi and -lunwind for linking
Summary:
We are going to have libc++abi.a and libunwind.a on AIX.
Add the necessary linking command to pick the libraries up.

Reviewed By: daltenty

Differential Revision: https://reviews.llvm.org/D102813
2021-05-27 15:48:53 +00:00
Mitch Phillips f7c5c0d87b Revert "[Scudo] Make -fsanitize=scudo use standalone. Migrate tests."
This reverts commit 6911114d8c.

Broke the QEMU sanitizer bots due to a missing header dependency. This
actually needs to be fixed on the bot-side, but for now reverting this
patch until I can fix up the bot.
2021-05-26 10:50:26 -07:00
Mitch Phillips 6911114d8c [Scudo] Make -fsanitize=scudo use standalone. Migrate tests.
This patch moves -fsanitize=scudo to link the standalone scudo library,
rather than the original compiler-rt based library. This is one of the
major remaining roadblocks to deleting the compiler-rt based scudo,
which should not be used any more. The standalone Scudo is better in
pretty much every way and is much more suitable for production usage.

As well as patching the litmus tests for checking that the
scudo_standalone lib is linked instead of the scudo lib, this patch also
ports all the scudo lit tests to run under scudo standalone.

This patch also adds a feature to scudo standalone that was under test
in the original scudo - that arguments passed to an aligned operator new
were checked that the alignment was a power of two.

Some lit tests could not be migrated, due to the following issues:
 1. Features that aren't supported in scudo standalone, like the rss
 limit.
 2. Different quarantine implementation where the test needs some more
 thought.
 3. Small bugs in scudo standalone that should probably be fixed, like
 the Secondary allocator having a full page on the LHS of an allocation
 that only contains the chunk header, so underflows by <= a page aren't
 caught.
 4. Slight differences in behaviour that's technically correct, like
 'realloc(malloc(1), 0)' returns nullptr in standalone, but a real
 pointer in old scudo.
 5. Some tests that might be migratable, but not easily.

Tests that are obviously not applicable to scudo standalone (like
testing that no sanitizer symbols made it into the DSO) have been
deleted.

After this patch, the remaining work is:
 1. Update the Scudo documentation. The flags have changed, etc.
 2. Delete the old version of scudo.
 3. Patch up the tests in lit-unmigrated, or fix Scudo standalone.

Reviewed By: cryptoad, vitalybuka

Differential Revision: https://reviews.llvm.org/D102543
2021-05-26 10:03:17 -07:00
Hans Wennborg a8f75d497d [clang-cl] Add driver support for /std:c++20 and bump /std:c++latest (PR50465)
VS 2019 16.11 (just released in Preview) is adding support for the
/std:c++20 option and bumping /std:c++latest to "post-c++20". This
updates clang-cl to match.

Differential revision: https://reviews.llvm.org/D103155
2021-05-26 16:05:52 +02:00
Jake Egan 5bc644aeca Revert "[AIX] Avoid structor alias; die before bad alias codegen"
Avoiding structor alias is no longer needed because AIX now has an alias implementation here: https://reviews.llvm.org/D83252.

This reverts commit b116ded57d.

Reviewed By: jasonliu

Differential Revision: https://reviews.llvm.org/D102724
2021-05-25 15:07:40 -04:00
David Spickett 8427053f81 [clang][ARM] When handling multiple -mimplicit-it mark all as used
Since 4468e5b899 clang will prefer
the last one it finds of "-mimplicit-it" or "-Wa,-mimplicit-it".

Due to a mistake in that patch the compiler argument "-mimplicit-it"
was never marked as used, even if it was the last one and was passed
to llvm.

Move the Claim call back to the start of the loop and update
the testing to check we don't get any unused argument warnings.

Reviewed By: mstorsjo

Differential Revision: https://reviews.llvm.org/D103086
2021-05-25 14:53:07 +00:00
Petr Hosek 5ff79f001f Revert "[Driver] Support libc++ in MSVC"
This reverts commit b604301be3 since
it caused compilation failure in sanitizer_unwind_win.cpp when using
the runtimes build.
2021-05-22 15:49:46 -07:00
Petr Hosek b604301be3 [Driver] Support libc++ in MSVC
This implements support for using libc++ headers and library in the MSVC
toolchain.  We only support libc++ that is a part of the toolchain, and
not headers installed elsewhere on the system.

Differential Revision: https://reviews.llvm.org/D101479
2021-05-22 13:32:23 -07:00
Yaxun (Sam) Liu bf6124580d [HIP] support ThinLTO
Add options -[no-]offload-lto and -foffload-lto=[thin,full] for controlling
LTO for offload compilation. Allow LTO for AMDGPU target.

AMDGPU target does not support codegen of object files containing
call of external functions, therefore the LLVM module passed to
AMDGPU backend needs to contain definitions of all the callees.
An LLVM option is added to allow function importer to import
functions with noinline attribute.

HIP toolchain passes proper LLVM options to lld to make sure
function importer imports definitions of all the callees.

Reviewed by: Teresa Johnson, Artem Belevich

Differential Revision: https://reviews.llvm.org/D99683
2021-05-22 10:48:34 -04:00
Martin Storsjö 4468e5b899 [clang] Don't pass multiple backend options if mixing -mimplicit-it and -Wa,-mimplicit-it
If multiple instances of the -arm-implicit-it option is passed to
the backend, it errors out.

Also fix cases where there are multiple -Wa,-mimplicit-it; the existing
tests indicate that the last one specified takes effect, while in
practice it passed double options, which didn't work as intended.

Differential Revision: https://reviews.llvm.org/D102812
2021-05-22 00:05:31 +03:00
Timm Bäder 95423c7c99 [clang][driver] Treat -flto=[auto,jobserver] as -flto
Instead of ignoring flto=auto and -flto=jobserver, treat them as -flto
and pass -flto=full along.

Differential Revision: https://reviews.llvm.org/D102479
2021-05-21 08:38:41 +02:00
Min-Yih Hsu e620bea211 [M68k] Allow user to preserve certain registers
Add `-ffixed-a[0-6]` and `-ffixed-d[0-7]` and the corresponding
subtarget features to prevent certain register from being allocated.

Differential Revision: https://reviews.llvm.org/D102805
2021-05-20 13:57:22 -07:00
Daniel Kiss 801ab71032 [ARM][AArch64] SLSHardening: make non-comdat thunks possible
Linker scripts might not handle COMDAT sections. SLSHardeing adds
new section for each __llvm_slsblr_thunk_xN. This new option allows
the generation of the thunks into the normal text section to handle these
exceptional cases.
,comdat or ,noncomdat can be added to harden-sls to control the codegen.
-mharden-sls=[all|retbr|blr],nocomdat.

Reviewed By: kristof.beyls

Differential Revision: https://reviews.llvm.org/D100546
2021-05-20 17:07:05 +02:00
Martin Storsjö 688b917b4b Revert "[Driver] Delete -mimplicit-it="
This reverts commit 2919222d80.

That commit broke backwards compatibility. Additionally, the
replacement, -Wa,-mimplicit-it, isn't yet supported by any stable
release of Clang.

See D102812 for a fix for the error cases when callers specify both
-mimplicit-it and -Wa,-mimplicit-it.
2021-05-20 00:17:50 +03:00
Melanie Blower d30dfa8676 [clang][patch] Add support for option -fextend-arguments={32,64}: widen integer arguments to int64 in unprototyped function calls
Reviewed By: Aaron Ballman

Differential Revision: https://reviews.llvm.org/D101640
2021-05-19 10:59:56 -04:00
Fangrui Song 2919222d80 [Driver] Delete -mimplicit-it=
This is a GNU as and Clang cc1as option, not a GCC option.
Users should specify `-Wa,-mimplicit-it=` instead.

Note: mixing the -m option and the -Wa, option doesn't work
`-Wa,-mimplicit-it=never -mimplicit-it=always` =>
`clang (LLVM option parsing): for the --arm-implicit-it option: may only occur zero or one times!`

Reviewed By: nickdesaulniers, raj.khem

Differential Revision: https://reviews.llvm.org/D102568
2021-05-18 10:57:24 -07:00
Aaron Ballman 6381664580 Introduce SYCL 2020 mode
Currently, we have support for SYCL 1.2.1 (also known as SYCL 2017).
This patch introduces the start of support for SYCL 2020 mode, which is
the latest SYCL standard available at (https://www.khronos.org/registry/SYCL/specs/sycl-2020/html/sycl-2020.html).
This sets the default SYCL to be 2020 in the driver, and introduces the
notion of a "default" version (set to 2020) when cc1 is in SYCL mode
but there was no explicit -sycl-std= specified on the command line.
2021-05-18 10:34:14 -04:00
Ten Tzen 797ad70152 [Windows SEH]: HARDWARE EXCEPTION HANDLING (MSVC -EHa) - Part 1
This patch is the Part-1 (FE Clang) implementation of HW Exception handling.

This new feature adds the support of Hardware Exception for Microsoft Windows
SEH (Structured Exception Handling).
This is the first step of this project; only X86_64 target is enabled in this patch.

Compiler options:
For clang-cl.exe, the option is -EHa, the same as MSVC.
For clang.exe, the extra option is -fasync-exceptions,
plus -triple x86_64-windows -fexceptions and -fcxx-exceptions as usual.

NOTE:: Without the -EHa or -fasync-exceptions, this patch is a NO-DIFF change.

The rules for C code:
For C-code, one way (MSVC approach) to achieve SEH -EHa semantic is to follow
three rules:
* First, no exception can move in or out of _try region., i.e., no "potential
  faulty instruction can be moved across _try boundary.
* Second, the order of exceptions for instructions 'directly' under a _try
  must be preserved (not applied to those in callees).
* Finally, global states (local/global/heap variables) that can be read
  outside of _try region must be updated in memory (not just in register)
  before the subsequent exception occurs.

The impact to C++ code:
Although SEH is a feature for C code, -EHa does have a profound effect on C++
side. When a C++ function (in the same compilation unit with option -EHa ) is
called by a SEH C function, a hardware exception occurs in C++ code can also
be handled properly by an upstream SEH _try-handler or a C++ catch(...).
As such, when that happens in the middle of an object's life scope, the dtor
must be invoked the same way as C++ Synchronous Exception during unwinding
process.

Design:
A natural way to achieve the rules above in LLVM today is to allow an EH edge
added on memory/computation instruction (previous iload/istore idea) so that
exception path is modeled in Flow graph preciously. However, tracking every
single memory instruction and potential faulty instruction can create many
Invokes, complicate flow graph and possibly result in negative performance
impact for downstream optimization and code generation. Making all
optimizations be aware of the new semantic is also substantial.

This design does not intend to model exception path at instruction level.
Instead, the proposed design tracks and reports EH state at BLOCK-level to
reduce the complexity of flow graph and minimize the performance-impact on CPP
code under -EHa option.

One key element of this design is the ability to compute State number at
block-level. Our algorithm is based on the following rationales:

A _try scope is always a SEME (Single Entry Multiple Exits) region as jumping
into a _try is not allowed. The single entry must start with a seh_try_begin()
invoke with a correct State number that is the initial state of the SEME.
Through control-flow, state number is propagated into all blocks. Side exits
marked by seh_try_end() will unwind to parent state based on existing
SEHUnwindMap[].
Note side exits can ONLY jump into parent scopes (lower state number).
Thus, when a block succeeds various states from its predecessors, the lowest
State triumphs others.  If some exits flow to unreachable, propagation on those
paths terminate, not affecting remaining blocks.
For CPP code, object lifetime region is usually a SEME as SEH _try.
However there is one rare exception: jumping into a lifetime that has Dtor but
has no Ctor is warned, but allowed:

Warning: jump bypasses variable with a non-trivial destructor

In that case, the region is actually a MEME (multiple entry multiple exits).
Our solution is to inject a eha_scope_begin() invoke in the side entry block to
ensure a correct State.

Implementation:
Part-1: Clang implementation described below.

Two intrinsic are created to track CPP object scopes; eha_scope_begin() and eha_scope_end().
_scope_begin() is immediately added after ctor() is called and EHStack is pushed.
So it must be an invoke, not a call. With that it's also guaranteed an
EH-cleanup-pad is created regardless whether there exists a call in this scope.
_scope_end is added before dtor(). These two intrinsics make the computation of
Block-State possible in downstream code gen pass, even in the presence of
ctor/dtor inlining.

Two intrinsic, seh_try_begin() and seh_try_end(), are added for C-code to mark
_try boundary and to prevent from exceptions being moved across _try boundary.
All memory instructions inside a _try are considered as 'volatile' to assure
2nd and 3rd rules for C-code above. This is a little sub-optimized. But it's
acceptable as the amount of code directly under _try is very small.

Part-2 (will be in Part-2 patch): LLVM implementation described below.

For both C++ & C-code, the state of each block is computed at the same place in
BE (WinEHPreparing pass) where all other EH tables/maps are calculated.
In addition to _scope_begin & _scope_end, the computation of block state also
rely on the existing State tracking code (UnwindMap and InvokeStateMap).

For both C++ & C-code, the state of each block with potential trap instruction
is marked and reported in DAG Instruction Selection pass, the same place where
the state for -EHsc (synchronous exceptions) is done.
If the first instruction in a reported block scope can trap, a Nop is injected
before this instruction. This nop is needed to accommodate LLVM Windows EH
implementation, in which the address in IPToState table is offset by +1.
(note the purpose of that is to ensure the return address of a call is in the
same scope as the call address.

The handler for catch(...) for -EHa must handle HW exception. So it is
'adjective' flag is reset (it cannot be IsStdDotDot (0x40) that only catches
C++ exceptions).
Suppress push/popTerminate() scope (from noexcept/noTHrow) so that HW
exceptions can be passed through.

Original llvm-dev [RFC] discussions can be found in these two threads below:
https://lists.llvm.org/pipermail/llvm-dev/2020-March/140541.html
https://lists.llvm.org/pipermail/llvm-dev/2020-April/141338.html

Differential Revision: https://reviews.llvm.org/D80344/new/
2021-05-17 22:42:17 -07:00
Nick Desaulniers 0f41778919 [AArch64] Support customizing stack protector guard
Follow up to D88631 but for aarch64; the Linux kernel uses the command
line flags:

1. -mstack-protector-guard=sysreg
2. -mstack-protector-guard-reg=sp_el0
3. -mstack-protector-guard-offset=0

to use the system register sp_el0 for the stack canary, enabling the
kernel to have a unique stack canary per task (like a thread, but not
limited to userspace as the kernel can preempt itself).

Address pr/47341 for aarch64.

Fixes: https://github.com/ClangBuiltLinux/linux/issues/289
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>

Reviewed By: xiangzhangllvm, DavidSpickett, dmgreen

Differential Revision: https://reviews.llvm.org/D100919
2021-05-17 11:49:22 -07:00
Yaxun (Sam) Liu 18cb17ce4c [HIP] Fix spack detection
Missing or duplicate spack package should not cause error, since
users may only installed llvm/clang package, or users may installed
duplicate HIP package but will use environment variable or compiler
option to choose HIP path.

The message about missing or duplicate spack package is informational,
therefore should be emitted only when -v is specified.

Reviewed by: Artem Belevich

Differential Revision: https://reviews.llvm.org/D102556
2021-05-17 13:24:05 -04:00
Matt Morehouse 5f58322368 [HWASan] Build separate LAM runtime on x86_64.
Since we have both aliasing mode and Intel LAM on x86_64, we need to
choose the mode at either run time or compile time.  This patch
implements the plumbing to build both and choose between them at
compile time.

Reviewed By: vitalybuka, eugenis

Differential Revision: https://reviews.llvm.org/D102286
2021-05-17 09:19:06 -07:00
Simon Pilgrim b89e09a19f Silence "Undefined or garbage value returned to caller" static analysis warning. NFCI. 2021-05-17 14:08:27 +01:00
Pengxuan Zheng c9b36a041f Support GCC's -fstack-usage flag
This patch adds support for GCC's -fstack-usage flag. With this flag, a stack
usage file (i.e., .su file) is generated for each input source file. The format
of the stack usage file is also similar to what is used by GCC. For each
function defined in the source file, a line with the following information is
produced in the .su file.

<source_file>:<line_number>:<function_name> <size_in_byte> <static/dynamic>

"Static" means that the function's frame size is static and the size info is an
accurate reflection of the frame size. While "dynamic" means the function's
frame size can only be determined at run-time because the function manipulates
the stack dynamically (e.g., due to variable size objects). The size info only
reflects the size of the fixed size frame objects in this case and therefore is
not a reliable measure of the total frame size.

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D100509
2021-05-15 10:22:49 -07:00
Matt Morehouse b7d1ab75cf [HWASan] Add aliasing flag and enable HWASan to use it.
-fsanitize-hwaddress-experimental-aliasing is intended to distinguish
aliasing mode from LAM mode on x86_64.  check-hwasan is configured
to use aliasing mode while check-hwasan-lam is configured to use LAM
mode.

The current patch doesn't actually do anything differently in the two
modes.  A subsequent patch will actually build the separate runtimes
and use them in each mode.

Currently LAM mode tests must be run in an emulator that
has LAM support.  To ensure LAM mode isn't broken by future patches, I
will next set up a QEMU buildbot to run the HWASan tests in LAM.

Reviewed By: vitalybuka

Differential Revision: https://reviews.llvm.org/D102288
2021-05-14 09:47:20 -07:00