Summary:
Internally in LLVM's metadata we use DW_OP_entry_value operations with
the same semantics as DWARF; that is, its operand specifies the number
of bytes that the entry value covers.
At the time of emitting entry values we don't know the emitted size of
the DWARF expression that the entry value will cover. Currently the size
is hardcoded to 1 in DIExpression, and other values causes the verifier
to fail. As the size is 1, that effectively means that we can only have
valid entry values for registers that can be encoded in one byte, which
are the registers with DWARF numbers 0 to 31 (as they can be encoded as
single-byte DW_OP_reg0..DW_OP_reg31 rather than a multi-byte
DW_OP_regx). It is a bit confusing, but it seems like llvm-dwarfdump
will print an operation "correctly", even if the byte size is less than
that, which may make it seem that we emit correct DWARF for registers
with DWARF numbers > 31. If you instead use readelf for such cases, it
will interpret the number of specified bytes as a DWARF expression. This
seems like a limitation in llvm-dwarfdump.
As suggested in D66746, a way forward would be to add an internal
variant of DW_OP_entry_value, DW_OP_LLVM_entry_value, whose operand
instead specifies the number of operations that the entry value covers,
and we then translate that into the byte size at the time of emission.
In this patch that internal operation is added. This patch keeps the
limitation that a entry value can only be applied to simple register
locations, but it will fix the issue with the size operand being
incorrect for DWARF numbers > 31.
Reviewers: aprantl, vsk, djtodoro, NikolaPrica
Reviewed By: aprantl
Subscribers: jyknight, fedor.sergeev, hiraditya, llvm-commits
Tags: #debug-info, #llvm
Differential Revision: https://reviews.llvm.org/D67492
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@374881 91177308-0d34-0410-b5e6-96231b3b80d8
Earlier in the year intrinsics for lrint, llrint, lround and llround were
added to llvm. The constrained versions are now implemented here.
Reviewed by: andrew.w.kaylor, craig.topper, cameron.mcinally
Approved by: craig.topper
Differential Revision: https://reviews.llvm.org/D64746
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@373900 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
The list of indirect labels should ALWAYS have their blockaddresses as
argument operands to the callbr (but not necessarily the other way
around). Add an invariant that checks this.
The verifier catches a bad test case that was added recently in r368478.
I think that was a simple mistake, and the test was made less strict in
regards to the precise addresses (as those weren't specifically the
point of the test).
This invariant will be used to find a reported bug.
Link: https://www.spinics.net/lists/arm-kernel/msg753473.html
Link: https://github.com/ClangBuiltLinux/linux/issues/649
Reviewers: craig.topper, void, chandlerc
Reviewed By: void
Subscribers: ychen, lebedev.ri, javed.absar, kristof.beyls, hiraditya, llvm-commits, srhines
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D67196
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@372923 91177308-0d34-0410-b5e6-96231b3b80d8
The static analyzer is warning about potential null dereferences, but we should be able to use cast<VectorType> directly and if not assert will fire for us.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@372529 91177308-0d34-0410-b5e6-96231b3b80d8
DIFlagBlockByRefStruct is an unused DIFlag that originally was used by
clang to express (Objective-)C block captures in debug info. For the
last year Clang has been emitting complex DIExpressions to describe
block captures instead, which makes all the code supporting this flag
redundant.
This patch removes the flag and all supporting "dead" code, so we can
reuse the bit for something else in the future.
Since this only affects debug info generated by Clang with the block
extension this mostly affects Apple platforms and I don't have any
bitcode compatibility concerns for removing this. The Verifier will
reject debug info that uses the bit and thus degrade gracefully when
LTO'ing older bitcode with a newer compiler.
rdar://problem/44304813
Differential Revision: https://reviews.llvm.org/D67453
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@372272 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Add an intrinsic that takes 2 unsigned integers with
the scale of them provided as the third argument and
performs fixed point multiplication on them. The
result is saturated and clamped between the largest and
smallest representable values of the first 2 operands.
This is a part of implementing fixed point arithmetic
in clang where some of the more complex operations
will be implemented as intrinsics.
Patch by: leonardchan, bjope
Reviewers: RKSimon, craig.topper, bevinh, leonardchan, lebedev.ri, spatel
Reviewed By: leonardchan
Subscribers: ychen, wuzish, nemanjai, MaskRay, jsji, jdoerfert, Ka-Ka, hiraditya, rjmccall, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D57836
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@371308 91177308-0d34-0410-b5e6-96231b3b80d8
This implements constrained floating point intrinsics for FP to signed and
unsigned integers.
Quoting from D32319:
The purpose of the constrained intrinsics is to force the optimizer to
respect the restrictions that will be necessary to support things like the
STDC FENV_ACCESS ON pragma without interfering with optimizations when
these restrictions are not needed.
Reviewed by: Andrew Kaylor, Craig Topper, Hal Finkel, Cameron McInally, Roman Lebedev, Kit Barton
Approved by: Craig Topper
Differential Revision: http://reviews.llvm.org/D63782
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@370228 91177308-0d34-0410-b5e6-96231b3b80d8
I noticed another instance of the issue where references to aliases were
being replaced with aliasees, this time in InstCombine. In the instance that
I saw it turned out to be only a QoI issue (a symbol ended up being missing
from the symbol table due to the last reference to the alias being removed,
preventing HWASAN from symbolizing a global reference), but it could easily
have manifested as incorrect behaviour.
Since this is the third such issue encountered (previously: D65118, D65314)
it seems to be time to address this common error/QoI issue once and for all
and make the strip* family of functions not look through aliases.
Includes a test for the specific issue that I saw, but no doubt there are
other similar bugs fixed here.
As with D65118 this has been tested to make sure that the optimization isn't
load bearing. I built Clang, Chromium for Linux, Android and Windows as well
as the test-suite and there were no size regressions.
Differential Revision: https://reviews.llvm.org/D66606
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@369697 91177308-0d34-0410-b5e6-96231b3b80d8
Now that we've moved to C++14, we no longer need the llvm::make_unique
implementation from STLExtras.h. This patch is a mechanical replacement
of (hopefully) all the llvm::make_unique instances across the monorepo.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@369013 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Allow IntToPtrInst to carry !dereferenceable metadata tag.
This is valid since !dereferenceable can be only be applied to
pointer type values.
Change-Id: If8a6e3c616f073d51eaff52ab74535c29ed497b4
Subscribers: llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D64954
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@366826 91177308-0d34-0410-b5e6-96231b3b80d8
Add "memtag" sanitizer that detects and mitigates stack memory issues
using armv8.5 Memory Tagging Extension.
It is similar in principle to HWASan, which is a software implementation
of the same idea, but there are enough differencies to warrant a new
sanitizer type IMHO. It is also expected to have very different
performance properties.
The new sanitizer does not have a runtime library (it may grow one
later, along with a "debugging" mode). Similar to SafeStack and
StackProtector, the instrumentation pass (in a follow up change) will be
inserted in all cases, but will only affect functions marked with the
new sanitize_memtag attribute.
Reviewers: pcc, hctim, vitalybuka, ostannard
Subscribers: srhines, mehdi_amini, javed.absar, kristof.beyls, hiraditya, cryptoad, steven_wu, dexonsmith, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D64169
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@366123 91177308-0d34-0410-b5e6-96231b3b80d8
Introduce and deduce "nosync" function attribute to indicate that a function
does not synchronize with another thread in a way that other thread might free memory.
Reviewers: jdoerfert, jfb, nhaehnle, arsenm
Subscribers: wdng, hfinkel, nhaenhle, mehdi_amini, steven_wu,
dexonsmith, arsenm, uenoku, hiraditya, jfb, llvm-commits
Differential Revision: https://reviews.llvm.org/D62766
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@365830 91177308-0d34-0410-b5e6-96231b3b80d8
The IRBuilder has calls to create floating point instructions like fadd.
It does not have calls to create constrained versions of them. This patch
adds support for constrained creation of fadd, fsub, fmul, fdiv, and frem.
Reviewed by: John McCall, Sanjay Patel
Approved by: John McCall
Differential Revision: https://reviews.llvm.org/D53157
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@365339 91177308-0d34-0410-b5e6-96231b3b80d8
This patch adds a function attribute, nofree, to indicate that a function does
not, directly or indirectly, call a memory-deallocation function (e.g., free,
C++'s operator delete).
Reviewers: jdoerfert
Differential Revision: https://reviews.llvm.org/D49165
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@365336 91177308-0d34-0410-b5e6-96231b3b80d8
Reintroduces the scalable vector IR type from D32530, after it was reverted
a couple of times due to increasing chromium LTO build times. This latest
incarnation removes the walk over aggregate types from the verifier entirely,
in favor of rejecting scalable vectors in the isValidElementType methods in
ArrayType and StructType. This removes the 70% degradation observed with
the second repro tarball from PR42210.
Reviewers: thakis, hans, rengolin, sdesmalen
Reviewed By: sdesmalen
Differential Revision: https://reviews.llvm.org/D64079
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@365203 91177308-0d34-0410-b5e6-96231b3b80d8
This patch introduces a new function attribute, willreturn, to indicate
that a call of this function will either exhibit undefined behavior or
comes back and continues execution at a point in the existing call stack
that includes the current invocation.
This attribute guarantees that the function does not have any endless
loops, endless recursion, or terminating functions like abort or exit.
Patch by Hideto Ueno (@uenoku)
Reviewers: jdoerfert
Subscribers: mehdi_amini, hiraditya, steven_wu, dexonsmith, lebedev.ri, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D62801
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@364555 91177308-0d34-0410-b5e6-96231b3b80d8
We saw a 70% ThinLTO link time increase in Chromium for Android, see
crbug.com/978817. Sounds like more of PR42210.
> Recommit of D32530 with a few small changes:
> - Stopped recursively walking through aggregates in
> the verifier, so that we don't impose too much
> overhead on large modules under LTO (see PR42210).
> - Changed tests to match; the errors are slightly
> different since they only report the array or
> struct that actually contains a scalable vector,
> rather than all aggregates which contain one in
> a nested member.
> - Corrected an older comment
>
> Reviewers: thakis, rengolin, sdesmalen
>
> Reviewed By: sdesmalen
>
> Differential Revision: https://reviews.llvm.org/D63321
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@364543 91177308-0d34-0410-b5e6-96231b3b80d8
Recommit of D32530 with a few small changes:
- Stopped recursively walking through aggregates in
the verifier, so that we don't impose too much
overhead on large modules under LTO (see PR42210).
- Changed tests to match; the errors are slightly
different since they only report the array or
struct that actually contains a scalable vector,
rather than all aggregates which contain one in
a nested member.
- Corrected an older comment
Reviewers: thakis, rengolin, sdesmalen
Reviewed By: sdesmalen
Differential Revision: https://reviews.llvm.org/D63321
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@363658 91177308-0d34-0410-b5e6-96231b3b80d8
Extend the mechanism to overload intrinsic arguments by using either
backward or forward references to the overloadable arguments.
In for example:
def int_something : Intrinsic<[LLVMPointerToElt<0>],
[llvm_anyvector_ty], []>;
LLVMPointerToElt<0> is a forward reference to the overloadable operand
of type 'llvm_anyvector_ty' and would allow intrinsics such as:
declare i32* @llvm.something.v4i32(<4 x i32>);
declare i64* @llvm.something.v2i64(<2 x i64>);
where the result pointer type is deduced from the element type of the
first argument.
If the returned pointer is not a pointer to the element type, LLVM will
give an error:
Intrinsic has incorrect return type!
i64* (<4 x i32>)* @llvm.something.v4i32
Reviewers: RKSimon, arsenm, rnk, greened
Reviewed By: arsenm
Differential Revision: https://reviews.llvm.org/D62995
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@363233 91177308-0d34-0410-b5e6-96231b3b80d8
This reverts commit f4fc01f8dd3a5dfd2060d1ad0df6b90e8351ddf7.
It caused a 3-4x slowdown when doing thinlto links, PR42210.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@362913 91177308-0d34-0410-b5e6-96231b3b80d8
When we switch to opaque pointer types we will need some way to describe
how many bytes a 'byval' parameter should occupy on the stack. This adds
a (for now) optional extra type parameter.
If present, the type must match the pointee type of the argument.
The original commit did not remap byval types when linking modules, which broke
LTO. This version fixes that.
Note to front-end maintainers: if this causes test failures, it's probably
because the "byval" attribute is printed after attributes without any parameter
after this change.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@362128 91177308-0d34-0410-b5e6-96231b3b80d8
When we switch to opaque pointer types we will need some way to describe
how many bytes a 'byval' parameter should occupy on the stack. This adds
a (for now) optional extra type parameter.
If present, the type must match the pointee type of the argument.
Note to front-end maintainers: if this causes test failures, it's probably
because the "byval" attribute is printed after attributes without any parameter
after this change.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@362012 91177308-0d34-0410-b5e6-96231b3b80d8
* Adds a 'scalable' flag to VectorType
* Adds an 'ElementCount' class to VectorType to pass (possibly scalable) vector lengths, with overloaded operators.
* Modifies existing helper functions to use ElementCount
* Adds support for serializing/deserializing to/from both textual and bitcode IR formats
* Extends the verifier to reject global variables of scalable types
* Updates documentation
See the latest version of the RFC here: http://lists.llvm.org/pipermail/llvm-dev/2018-July/124396.html
Reviewers: rengolin, lattner, echristo, chandlerc, hfinkel, rkruppe, samparker, SjoerdMeijer, greened, sebpop
Reviewed By: hfinkel, sebpop
Differential Revision: https://reviews.llvm.org/D32530
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@361953 91177308-0d34-0410-b5e6-96231b3b80d8
This patch add the ISD::LRINT and ISD::LLRINT along with new
intrinsics. The changes are straightforward as for other
floating-point rounding functions, with just some adjustments
required to handle the return value being an interger.
The idea is to optimize lrint/llrint generation for AArch64
in a subsequent patch. Current semantic is just route it to libm
symbol.
Reviewed By: craig.topper
Differential Revision: https://reviews.llvm.org/D62017
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@361875 91177308-0d34-0410-b5e6-96231b3b80d8
Add an intrinsic that takes 2 signed integers with the scale of them provided
as the third argument and performs fixed point multiplication on them. The
result is saturated and clamped between the largest and smallest representable
values of the first 2 operands.
This is a part of implementing fixed point arithmetic in clang where some of
the more complex operations will be implemented as intrinsics.
Differential Revision: https://reviews.llvm.org/D55720
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@361289 91177308-0d34-0410-b5e6-96231b3b80d8
We shouldn't really make assumptions about possible sizes for long and long long. And longer term we should probably support vectorizing these intrinsics. By making the result types not fixed we can support vectors as well.
Differential Revision: https://reviews.llvm.org/D62026
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@361169 91177308-0d34-0410-b5e6-96231b3b80d8
The 3-field form was introduced by D3499 in 2014 and the legacy 2-field
form was planned to be removed in LLVM 4.0
For the textual format, this patch migrates the existing 2-field form to
use the 3-field form and deletes the compatibility code.
test/Verifier/global-ctors-2.ll checks we have a friendly error message.
For bitcode, lib/IR/AutoUpgrade UpgradeGlobalVariables will upgrade the
2-field form (add i8* null as the third field).
Reviewed By: rnk, dexonsmith
Differential Revision: https://reviews.llvm.org/D61547
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@360742 91177308-0d34-0410-b5e6-96231b3b80d8
The new fptrunc and fpext intrinsics are constrained versions of the
regular fptrunc and fpext instructions.
Reviewed by: Andrew Kaylor, Craig Topper, Cameron McInally, Conner Abbot
Approved by: Craig Topper
Differential Revision: https://reviews.llvm.org/D55897
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@360581 91177308-0d34-0410-b5e6-96231b3b80d8
DWARF5, 2.12 20ff says that
Any debugging information entry representing a pointer or reference
type [may have a DW_AT_address_class attribute].
The existing code (https://reviews.llvm.org/D29670) seems to take a
quite literal interpretation of that wording. I don't see a reason why
an rvalue reference isn't a reference type in the spirit of that
paragraph. This patch allows rvalue references to also have address
spaces.
rdar://problem/50511483
Differential Revision: https://reviews.llvm.org/D61625
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@360176 91177308-0d34-0410-b5e6-96231b3b80d8
COMMON blocks are a feature of Fortran that has no direct analog in C languages, but they are similar to data sections in assembly language programming. A COMMON block is a named area of memory that holds a collection of variables. Fortran subprograms may map the COMMON block memory area to their own, possibly distinct, non-empty list of variables. A Fortran COMMON block might look like the following example.
COMMON /ALPHA/ I, J
For this construct, the compiler generates a new scope-like DI construct (!DICommonBlock) into which variables (see I, J above) can be placed. As the common block implies a range of storage with global lifetime, the !DICommonBlock refers to a !DIGlobalVariable. The Fortran variable that comprise the COMMON block are also linked via metadata to offsets within the global variable that stands for the entire common block.
@alpha_ = common global %alphabytes_ zeroinitializer, align 64, !dbg !27, !dbg !30, !dbg !33!14 = distinct !DISubprogram(…)
!20 = distinct !DICommonBlock(scope: !14, declaration: !25, name: "alpha")
!25 = distinct !DIGlobalVariable(scope: !20, name: "common alpha", type: !24)
!27 = !DIGlobalVariableExpression(var: !25, expr: !DIExpression())
!29 = distinct !DIGlobalVariable(scope: !20, name: "i", file: !3, type: !28)
!30 = !DIGlobalVariableExpression(var: !29, expr: !DIExpression())
!31 = distinct !DIGlobalVariable(scope: !20, name: "j", file: !3, type: !28)
!32 = !DIExpression(DW_OP_plus_uconst, 4)
!33 = !DIGlobalVariableExpression(var: !31, expr: !32)
The DWARF generated for this is as follows.
DW_TAG_common_block:
DW_AT_name: alpha
DW_AT_location: @alpha_+0
DW_TAG_variable:
DW_AT_name: common alpha
DW_AT_type: array of 8 bytes
DW_AT_location: @alpha_+0
DW_TAG_variable:
DW_AT_name: i
DW_AT_type: integer*4
DW_AT_location: @Alpha+0
DW_TAG_variable:
DW_AT_name: j
DW_AT_type: integer*4
DW_AT_location: @Alpha+4
Patch by Eric Schweitz!
Differential Revision: https://reviews.llvm.org/D54327
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@357934 91177308-0d34-0410-b5e6-96231b3b80d8
This adds ConstantRange::getFull(BitWidth) and
ConstantRange::getEmpty(BitWidth) named constructors as more readable
alternatives to the current ConstantRange(BitWidth, /* full */ false)
and similar. Additionally private getFull() and getEmpty() member
functions are added which return a full/empty range with the same bit
width -- these are commonly needed inside ConstantRange.cpp.
The IsFullSet argument in the ConstantRange(BitWidth, IsFullSet)
constructor is now mandatory for the few usages that still make use of it.
Differential Revision: https://reviews.llvm.org/D59716
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@356852 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
In the new wasm EH proposal, `rethrow` takes an `except_ref` argument.
This change was missing in r352598.
This patch adds `llvm.wasm.rethrow.in.catch` intrinsic. This is an
intrinsic that's gonna eventually be lowered to wasm `rethrow`
instruction, but this intrinsic can appear only within a catchpad or a
cleanuppad scope. Also this intrinsic needs to be invokable - otherwise
EH pad successor for it will not be correctly generated in clang.
This also adds lowering logic for this intrinsic in
`SelectionDAGBuilder::visitInvoke`. This routine is basically a
specialized and simplified version of
`SelectionDAGBuilder::visitTargetIntrinsic`, but we can't use it
because if is only for `CallInst`s.
This deletes the previous `llvm.wasm.rethrow` intrinsic and related
tests, which was meant to be used within a `__cxa_rethrow` library
function. Turned out this needs some more logic, so the intrinsic for
this purpose will be added later.
LateEHPrepare takes a result value of `catch` and inserts it into
matching `rethrow` as an argument.
`RETHROW_IN_CATCH` is a pseudo instruction that serves as a link between
`llvm.wasm.rethrow.in.catch` and the real wasm `rethrow` instruction. To
generate a `rethrow` instruction, we need an `except_ref` argument,
which is generated from `catch` instruction. But `catch` instrutions are
added in LateEHPrepare pass, so we use `RETHROW_IN_CATCH`, which takes
no argument, until we are able to correctly lower it to `rethrow` in
LateEHPrepare.
Reviewers: dschuff
Subscribers: sbc100, jgravelle-google, sunfish, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D59352
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@356316 91177308-0d34-0410-b5e6-96231b3b80d8
This indicates an intrinsic parameter is required to be a constant,
and should not be replaced with a non-constant value.
Add the attribute to all AMDGPU and generic intrinsics that comments
indicate it should apply to. I scanned other target intrinsics, but I
don't see any obvious comments indicating which arguments are intended
to be only immediates.
This breaks one questionable testcase for the autoupgrade. I'm unclear
on whether the autoupgrade is supposed to really handle declarations
which were never valid. The verifier fails because the attributes now
refer to a parameter past the end of the argument list.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@355981 91177308-0d34-0410-b5e6-96231b3b80d8
This patch accompanies the RFC posted here:
http://lists.llvm.org/pipermail/llvm-dev/2018-October/127239.html
This patch adds a new CallBr IR instruction to support asm-goto
inline assembly like gcc as used by the linux kernel. This
instruction is both a call instruction and a terminator
instruction with multiple successors. Only inline assembly
usage is supported today.
This also adds a new INLINEASM_BR opcode to SelectionDAG and
MachineIR to represent an INLINEASM block that is also
considered a terminator instruction.
There will likely be more bug fixes and optimizations to follow
this, but we felt it had reached a point where we would like to
switch to an incremental development model.
Patch by Craig Topper, Alexander Ivchenko, Mikhail Dvoretckii
Differential Revision: https://reviews.llvm.org/D53765
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@353563 91177308-0d34-0410-b5e6-96231b3b80d8
Add an intrinsic that takes 2 unsigned integers with the scale of them
provided as the third argument and performs fixed point multiplication on
them.
This is a part of implementing fixed point arithmetic in clang where some of
the more complex operations will be implemented as intrinsics.
Differential Revision: https://reviews.llvm.org/D55625
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@353059 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
UBSan wants to detect when unreachable code is actually reached, so it
adds instrumentation before every `unreachable` instruction. However,
the optimizer will remove code after calls to functions marked with
`noreturn`. To avoid this UBSan removes `noreturn` from both the call
instruction as well as from the function itself. Unfortunately, ASan
relies on this annotation to unpoison the stack by inserting calls to
`_asan_handle_no_return` before `noreturn` functions. This is important
for functions that do not return but access the the stack memory, e.g.,
unwinder functions *like* `longjmp` (`longjmp` itself is actually
"double-proofed" via its interceptor). The result is that when ASan and
UBSan are combined, the `noreturn` attributes are missing and ASan
cannot unpoison the stack, so it has false positives when stack
unwinding is used.
Changes:
# UBSan now adds the `expect_noreturn` attribute whenever it removes
the `noreturn` attribute from a function
# ASan additionally checks for the presence of this attribute
Generated code:
```
call void @__asan_handle_no_return // Additionally inserted to avoid false positives
call void @longjmp
call void @__asan_handle_no_return
call void @__ubsan_handle_builtin_unreachable
unreachable
```
The second call to `__asan_handle_no_return` is redundant. This will be
cleaned up in a follow-up patch.
rdar://problem/40723397
Reviewers: delcypher, eugenis
Tags: #sanitizers
Differential Revision: https://reviews.llvm.org/D56624
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@352003 91177308-0d34-0410-b5e6-96231b3b80d8
