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Annotations in LLVM"
This patch contains the basic functionality for reporting potentially
incorrect usage of __builtin_expect() by comparing the developer's
annotation against a collected PGO profile. A more detailed proposal and
discussion appears on the CFE-dev mailing list
(http://lists.llvm.org/pipermail/cfe-dev/2019-July/062971.html) and a
prototype of the initial frontend changes appear here in D65300
We revised the work in D65300 by moving the misexpect check into the
LLVM backend, and adding support for IR and sampling based profiles, in
addition to frontend instrumentation.
We add new misexpect metadata tags to those instructions directly
influenced by the llvm.expect intrinsic (branch, switch, and select)
when lowering the intrinsics. The misexpect metadata contains
information about the expected target of the intrinsic so that we can
check against the correct PGO counter when emitting diagnostics, and the
compiler's values for the LikelyBranchWeight and UnlikelyBranchWeight.
We use these branch weight values to determine when to emit the
diagnostic to the user.
A future patch should address the comment at the top of
LowerExpectIntrisic.cpp to hoist the LikelyBranchWeight and
UnlikelyBranchWeight values into a shared space that can be accessed
outside of the LowerExpectIntrinsic pass. Once that is done, the
misexpect metadata can be updated to be smaller.
In the long term, it is possible to reconstruct portions of the
misexpect metadata from the existing profile data. However, we have
avoided this to keep the code simple, and because some kind of metadata
tag will be required to identify which branch/switch/select instructions
are influenced by the use of llvm.expect
Patch By: paulkirth
Differential Revision: https://reviews.llvm.org/D66324
llvm-svn: 371635
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Annotations in LLVM"
This reverts commit r371584. It introduced a dependency from compiler-rt
to llvm/include/ADT, which is problematic for multiple reasons.
One is that it is a novel dependency edge, which needs cross-compliation
machinery for llvm/include/ADT (yes, it is true that right now
compiler-rt included only header-only libraries, however, if we allow
compiler-rt to depend on anything from ADT, other libraries will
eventually get used).
Secondly, depending on ADT from compiler-rt exposes ADT symbols from
compiler-rt, which would cause ODR violations when Clang is built with
the profile library.
llvm-svn: 371598
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linkage type
Multi-versioned functions defined by cpu_dispatch and implemented with IFunc
can not be called outside the translation units where they are defined due to
lack of symbols. This patch add function aliases for these functions and thus
make them visible outside.
Differential Revision: https://reviews.llvm.org/D67058
Patch by Senran Zhang
llvm-svn: 371586
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This patch contains the basic functionality for reporting potentially
incorrect usage of __builtin_expect() by comparing the developer's
annotation against a collected PGO profile. A more detailed proposal and
discussion appears on the CFE-dev mailing list
(http://lists.llvm.org/pipermail/cfe-dev/2019-July/062971.html) and a
prototype of the initial frontend changes appear here in D65300
We revised the work in D65300 by moving the misexpect check into the
LLVM backend, and adding support for IR and sampling based profiles, in
addition to frontend instrumentation.
We add new misexpect metadata tags to those instructions directly
influenced by the llvm.expect intrinsic (branch, switch, and select)
when lowering the intrinsics. The misexpect metadata contains
information about the expected target of the intrinsic so that we can
check against the correct PGO counter when emitting diagnostics, and the
compiler's values for the LikelyBranchWeight and UnlikelyBranchWeight.
We use these branch weight values to determine when to emit the
diagnostic to the user.
A future patch should address the comment at the top of
LowerExpectIntrisic.cpp to hoist the LikelyBranchWeight and
UnlikelyBranchWeight values into a shared space that can be accessed
outside of the LowerExpectIntrinsic pass. Once that is done, the
misexpect metadata can be updated to be smaller.
In the long term, it is possible to reconstruct portions of the
misexpect metadata from the existing profile data. However, we have
avoided this to keep the code simple, and because some kind of metadata
tag will be required to identify which branch/switch/select instructions
are influenced by the use of llvm.expect
Patch By: paulkirth
Differential Revision: https://reviews.llvm.org/D66324
llvm-svn: 371584
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constant.
If the constexpr variable is partially initialized, the initializer can
be emitted as the structure, not as an array, because of some early
optimizations. The llvm variable gets the type from this constant and,
thus, gets the type which is pointer to struct rather than pointer to an
array. We need to convert this type to be truely array, otherwise it may
lead to the compiler crash when trying to emit array subscript
expression.
llvm-svn: 371548
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Annotations in LLVM"
This reverts commit r371484: this broke sanitizer-x86_64-linux-fast bot.
llvm-svn: 371488
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This patch contains the basic functionality for reporting potentially
incorrect usage of __builtin_expect() by comparing the developer's
annotation against a collected PGO profile. A more detailed proposal and
discussion appears on the CFE-dev mailing list
(http://lists.llvm.org/pipermail/cfe-dev/2019-July/062971.html) and a
prototype of the initial frontend changes appear here in D65300
We revised the work in D65300 by moving the misexpect check into the
LLVM backend, and adding support for IR and sampling based profiles, in
addition to frontend instrumentation.
We add new misexpect metadata tags to those instructions directly
influenced by the llvm.expect intrinsic (branch, switch, and select)
when lowering the intrinsics. The misexpect metadata contains
information about the expected target of the intrinsic so that we can
check against the correct PGO counter when emitting diagnostics, and the
compiler's values for the LikelyBranchWeight and UnlikelyBranchWeight.
We use these branch weight values to determine when to emit the
diagnostic to the user.
A future patch should address the comment at the top of
LowerExpectIntrisic.cpp to hoist the LikelyBranchWeight and
UnlikelyBranchWeight values into a shared space that can be accessed
outside of the LowerExpectIntrinsic pass. Once that is done, the
misexpect metadata can be updated to be smaller.
In the long term, it is possible to reconstruct portions of the
misexpect metadata from the existing profile data. However, we have
avoided this to keep the code simple, and because some kind of metadata
tag will be required to identify which branch/switch/select instructions
are influenced by the use of llvm.expect
Patch By: paulkirth
Differential Revision: https://reviews.llvm.org/D66324
llvm-svn: 371484
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We're running into linker errors from missing sancov sections:
```
ld.lld: error: relocation refers to a discarded section: __sancov_guards
>>> defined in user-arm64-ubsan-sancov-full.shlib/obj/third_party/ulib/scudo/scudo.wrappers_c.cc.o
>>> referenced by common.h:26 (../../zircon/third_party/ulib/scudo/common.h:26)
... many other references
```
I believe this is due to a pass in the default pipeline that somehow discards
these sections. The ModuleSanitizerCoveragePass was initially added at the
start of the pipeline. This now adds it to the end of the pipeline for
optimized and unoptimized builds.
Differential Revision: https://reviews.llvm.org/D67323
llvm-svn: 371326
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Clang patch to adapt to LLVM changes in D66428 that make the TLI
require a Function. There is no longer a module-level
TargetLibraryAnalysis, so remove its registration
llvm-svn: 371285
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This avoids cloning variadic virtual methods when the target supports
musttail and the return type is not covariant. I think we never
implemented this previously because it doesn't handle the covariant
case. But, in the MS ABI, there are some cases where vtable thunks must
be emitted even when the variadic method defintion is not available, so
it looks like we need to implement this. Do it for both ABIs, since it's
a nice size improvement and simplification for Itanium.
Emit an error when emitting thunks for variadic methods with a covariant
return type. This case is essentially not implementable unless the ABI
provides a way to perfectly forward variadic arguments without a tail
call.
Fixes PR43173.
Differential Revision: https://reviews.llvm.org/D67028
llvm-svn: 371269
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Will be easier to add a new 'check' in a follow-up.
This was originally part of https://reviews.llvm.org/D67122
llvm-svn: 371208
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EmitGEPOffsetInBytes() helper
It shouldn't really be inlined into the EmitCheckedInBoundsGEP().
Refactoring it beforehand will make follow-up changes more obvious.
This was originally part of https://reviews.llvm.org/D67122
llvm-svn: 371207
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pointer-overflow check
It's rather eye-twiching, some comments may help here..
This was originally part of https://reviews.llvm.org/D67122
llvm-svn: 371206
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As far as I can tell, gcc passes 256/512 bit vectors __int128 in memory. And passes a vector of 1 _int128 in an xmm register. The backend considers <X x i128> as an illegal type and will scalarize any arguments with that type. So we need to coerce the argument types in the frontend to match to avoid the illegal type.
I'm restricting this to change to Linux and NetBSD based on the
how similar ABI changes have been handled in the past.
PS4, FreeBSD, and Darwin are unaffected. I've also added a
new -fclang-abi-compat version to restore the old behavior.
This issue was identified in PR42607. Though even with the types changed, we still seem to be doing some unnecessary stack realignment.
llvm-svn: 371169
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mark them as artificial
llvm-svn: 371113
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as artificial
Differential Revision: https://reviews.llvm.org/D66328
llvm-svn: 371080
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Summary:
r337347 added support for the Signal Processing Engine (SPE) to LLVM.
This follows that up with the clang side.
This adds -mspe and -mno-spe, to match GCC.
Subscribers: nemanjai, kbarton, cfe-commits
Differential Revision: https://reviews.llvm.org/D49754
llvm-svn: 371066
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This essentially reverts changes from r361400 while keeping behavior for
CodeView.
Reviewers: akhuang, rnk, probinson
Reviewed by: rnk
Subscribers: cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D67141
llvm-svn: 370981
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This patch merges the sancov module and funciton passes into one module pass.
The reason for this is because we ran into an out of memory error when
attempting to run asan fuzzer on some protobufs (pc.cc files). I traced the OOM
error to the destructor of SanitizerCoverage where we only call
appendTo[Compiler]Used which calls appendToUsedList. I'm not sure where precisely
in appendToUsedList causes the OOM, but I am able to confirm that it's calling
this function *repeatedly* that causes the OOM. (I hacked sancov a bit such that
I can still create and destroy a new sancov on every function run, but only call
appendToUsedList after all functions in the module have finished. This passes, but
when I make it such that appendToUsedList is called on every sancov destruction,
we hit OOM.)
I don't think the OOM is from just adding to the SmallSet and SmallVector inside
appendToUsedList since in either case for a given module, they'll have the same
max size. I suspect that when the existing llvm.compiler.used global is erased,
the memory behind it isn't freed. I could be wrong on this though.
This patch works around the OOM issue by just calling appendToUsedList at the
end of every module run instead of function run. The same amount of constants
still get added to llvm.compiler.used, abd we make the pass usage and logic
simpler by not having any inter-pass dependencies.
Differential Revision: https://reviews.llvm.org/D66988
llvm-svn: 370971
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Differential Revision: https://reviews.llvm.org/D67048
llvm-svn: 370808
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Summary:
Adds clang builtins and LLVM intrinsics for these experimental
instructions. They are not implemented in engines yet, but that is ok
because the user must opt into using them by calling the builtins.
Reviewers: aheejin, dschuff
Reviewed By: aheejin
Subscribers: sbc100, jgravelle-google, hiraditya, sunfish, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D67020
llvm-svn: 370556
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Summary:
Nico Weber reported that the following code:
char buf[9];
asm("" : "=r" (buf));
yields the "impossible constraint in asm: can't store struct into a register"
error message, although |buf| is not a struct (see
http://crbug.com/999160).
Make the error message more generic and add a test for it.
Also make sure other tests in x86_64-PR42672.c check for the full error
message.
Reviewers: eli.friedman, thakis
Subscribers: cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D66948
llvm-svn: 370444
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Summary:
The "=r" output constraint for a structure variable passed to inline asm
shouldn't be converted to "=*r", as this changes the asm directive
semantics and prevents DSE optimizations.
Instead, preserve the constraints and return such structures as integers
of corresponding size, which are converted back to structures when
storing the result.
Fixes PR42672.
Subscribers: cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D65234
llvm-svn: 370335
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The previous version of this used CurFuncDecl in CodeGenFunction,
however this doesn't include lambdas. However, CurCodeDecl DOES. Switch
the check to use CurCodeDecl so that the actual function being emitted
gets checked, preventing an error in ISEL.
llvm-svn: 370261
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This implements the DWARF 5 feature described in:
http://dwarfstd.org/ShowIssue.php?issue=141212.1
To support recognizing anonymous structs:
struct A {
struct { // Anonymous struct
int y;
};
} a;
This patch adds support in CGDebugInfo::CreateLimitedType(...) for this new flag and an accompanying test to verify this feature.
Differential Revision: https://reviews.llvm.org/D66667
llvm-svn: 370107
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The backend default maximum should be the hardware maximum, so the
frontend should set the implementation defined default maximum.
llvm-svn: 370101
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Currently, clang accepts a union with a reference member when given the -fms-extensions flag. This change fixes the codegen for this case.
Patch by Dominic Ferreira.
llvm-svn: 370052
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Reviewers: eugenis
Subscribers: cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D66697
llvm-svn: 369980
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Reviewers: eugenis
Subscribers: hiraditya, cfe-commits, #sanitizers, llvm-commits
Tags: #clang, #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D66695
llvm-svn: 369979
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Summary:
Previously critical regions were emitted with the barrier making it a
worksharing construct though it is not. Also, it leads to incorrect
behavior in Cuda9+. Patch fixes this problem.
Reviewers: ABataev, jdoerfert
Subscribers: jholewinski, guansong, cfe-commits, grokos
Tags: #clang
Differential Revision: https://reviews.llvm.org/D66673
llvm-svn: 369946
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llvm-svn: 369803
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non-ordered loops.
According to OpenMP 5.0, 2.9.2 Worksharing-Loop Construct, Desription, If the static schedule kind is specified or if the ordered clause is specified, and if the nonmonotonic modifier is not specified, the effect is as if the monotonic modifier is specified. Otherwise, unless the monotonic modifier is specified, the effect is as if the nonmonotonic modifier is specified.
The first part of this requirement is implemented in runtime. Patch adds
support for the second, nonmonotonic, part of this requirement.
llvm-svn: 369801
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construct.
OpenMP 5.0 introduced new clause for declare target directive, device_type clause, which may accept values host, nohost, and any. Host means
that the function must be emitted only for the host, nohost - only for
the device, and any - for both, device and the host.
llvm-svn: 369775
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Summary:
It seems that CodeGen was always using ExternalLinkage when emitting a
GlobalDecl with __attribute__((alias)). This leads to symbol
redefinitions (ODR) that cause failures at link time for static aliases.
This is readily attempting to link an ARM (32b) allyesconfig Linux
kernel built with Clang.
Reported-by: nathanchance
Suggested-by: ihalip
Link: https://bugs.llvm.org/show_bug.cgi?id=42377
Link: https://github.com/ClangBuiltLinux/linux/issues/631
Reviewers: rsmith, aaron.ballman, erichkeane
Reviewed By: aaron.ballman
Subscribers: javed.absar, kristof.beyls, cfe-commits, srhines, ihalip, nathanchance
Tags: #clang
Differential Revision: https://reviews.llvm.org/D66492
llvm-svn: 369705
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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
llvm-svn: 369697
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It causes the build to fail with
"inlinable function call in a function with debug info must have a !dbg location"
in Chromium. See llvm-commits thread for more info.
(This also reverts the follow-up in r369474.)
> Fixes PR43012
>
> Differential Revision: https://reviews.llvm.org/D66328
llvm-svn: 369633
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pass manager
Match the behavior of D65009 under the new pass manager. This addresses
the test clang/test/CodeGen/split-lto-unit.c when running under the new
PM.
Differential Revision: https://reviews.llvm.org/D66488
llvm-svn: 369550
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Fixes PR43012
Differential Revision: https://reviews.llvm.org/D66328
llvm-svn: 369458
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Summary:
Add `Frontend` time trace entry to `HandleTranslationUnit()` function.
Add test to check all codegen blocks are inside frontend blocks.
Also, change `--time-trace-granularity` option a bit to make sure very small
time blocks are outputed to json-file when using `--time-trace-granularity=0`.
This fixes http://llvm.org/pr41969
Reviewers: russell.gallop, lebedev.ri, thakis
Reviewed By: russell.gallop
Subscribers: vsapsai, aras-p, lebedev.ri, hiraditya, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D63325
llvm-svn: 369308
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CGLoopInfo was keeping pointers to parent loop LoopInfos, but when the loop info vector grew, it reallocated the storage and invalidated all of the parent pointers, causing use-after-free. Manage the lifetimes of the LoopInfos separately so that the pointers aren't stale.
Patch by Bevin Hansson.
llvm-svn: 369259
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Summary:
D66168 passes size 0 structs indirectly, while the wasm backend expects it to
be passed directly. This causes subsequent variadic arguments to be read
incorrectly.
This diff changes it so that size 0 structs are passed directly.
Reviewers: dschuff, tlively, sbc100
Reviewed By: dschuff
Subscribers: jgravelle-google, aheejin, sunfish, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D66255
llvm-svn: 369042
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The implementation in libc++ takes O(1) compile time, ours was O(n).
llvm-svn: 368990
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New pragma "vectorize_predicate(enable)" now implies "vectorize(enable)",
and it is ignored when vectorization is disabled with e.g.
"vectorize(disable) vectorize_predicate(enable)".
Differential Revision: https://reviews.llvm.org/D65776
llvm-svn: 368970
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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.
Differential revision: https://reviews.llvm.org/D66259
llvm-svn: 368942
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Added basic support for non-rectangular loops. It requires an additional
analysis of min/max boundaries for non-rectangular loops. Since only
linear dependency is allowed, we can do this analysis.
llvm-svn: 368903
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SectionRef::getName() was changed to return Expected<> (D66089)
llvm-svn: 368825
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Summary: https://reviews.llvm.org/D50923 enabled the IR printing support for the new pass manager, but only for the case when `opt` tool is used as a driver. This patch is to enable the IR printing when `clang` is used as a driver.
Reviewers: fedor.sergeev, philip.pfaffe
Subscribers: cfe-commits, yamauchi, llvm-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D65975
llvm-svn: 368804
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Summary:
In the WebAssembly backend, when lowering variadic function calls, non-single
member aggregate type arguments are always passed by pointer.
However, when emitting va_arg code in clang, the arguments are instead read as
if they are passed directly. This results in the pointer being read as the
actual structure.
Fixes https://github.com/emscripten-core/emscripten/issues/9042.
Reviewers: tlively, sbc100, kripken, aheejin, dschuff
Reviewed By: dschuff
Subscribers: dschuff, jgravelle-google, sunfish, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D66168
llvm-svn: 368750
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Summary:
As explained in http://lists.llvm.org/pipermail/llvm-dev/2018-March/121924.html,
the LLVM coroutines transforms are not yet able to move the
instructions for UBSan null checking past coroutine suspend boundaries.
For now, disable all UBSan checks when generating code for coroutines
functions.
I also considered an approach where only '-fsanitize=null' would be disabled,
However in practice this led to other LLVM errors when writing object files:
"Cannot represent a difference across sections". For now, disable all
UBSan checks until coroutine transforms are updated to handle them.
Test Plan:
1. check-clang
2. Compile the program in https://gist.github.com/modocache/54a036c3bf9c06882fe85122e105d153
using the '-fsanitize=null' option and confirm it does not crash
during LLVM IR generation.
Reviewers: GorNishanov, vsk, eric_niebler, lewissbaker
Reviewed By: vsk
Subscribers: cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D44672
llvm-svn: 368675
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The default behavior of Clang's indirect function call checker will replace
the address of each CFI-checked function in the output file's symbol table
with the address of a jump table entry which will pass CFI checks. We refer
to this as making the jump table `canonical`. This property allows code that
was not compiled with ``-fsanitize=cfi-icall`` to take a CFI-valid address
of a function, but it comes with a couple of caveats that are especially
relevant for users of cross-DSO CFI:
- There is a performance and code size overhead associated with each
exported function, because each such function must have an associated
jump table entry, which must be emitted even in the common case where the
function is never address-taken anywhere in the program, and must be used
even for direct calls between DSOs, in addition to the PLT overhead.
- There is no good way to take a CFI-valid address of a function written in
assembly or a language not supported by Clang. The reason is that the code
generator would need to insert a jump table in order to form a CFI-valid
address for assembly functions, but there is no way in general for the
code generator to determine the language of the function. This may be
possible with LTO in the intra-DSO case, but in the cross-DSO case the only
information available is the function declaration. One possible solution
is to add a C wrapper for each assembly function, but these wrappers can
present a significant maintenance burden for heavy users of assembly in
addition to adding runtime overhead.
For these reasons, we provide the option of making the jump table non-canonical
with the flag ``-fno-sanitize-cfi-canonical-jump-tables``. When the jump
table is made non-canonical, symbol table entries point directly to the
function body. Any instances of a function's address being taken in C will
be replaced with a jump table address.
This scheme does have its own caveats, however. It does end up breaking
function address equality more aggressively than the default behavior,
especially in cross-DSO mode which normally preserves function address
equality entirely.
Furthermore, it is occasionally necessary for code not compiled with
``-fsanitize=cfi-icall`` to take a function address that is valid
for CFI. For example, this is necessary when a function's address
is taken by assembly code and then called by CFI-checking C code. The
``__attribute__((cfi_jump_table_canonical))`` attribute may be used to make
the jump table entry of a specific function canonical so that the external
code will end up taking a address for the function that will pass CFI checks.
Fixes PR41972.
Differential Revision: https://reviews.llvm.org/D65629
llvm-svn: 368495
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