Currently running the @insertelem_after_gep function below through the InstCombine pass with opt produces invalid IR.
Input:
```
define void @insertelem_after_gep(<16 x i32>* %t0) {
%t1 = bitcast <16 x i32>* %t0 to [16 x i32]*
%t2 = addrspacecast [16 x i32]* %t1 to [16 x i32] addrspace(3)*
%t3 = getelementptr inbounds [16 x i32], [16 x i32] addrspace(3)* %t2, i64 0, i64 0
%t4 = insertelement <16 x i32 addrspace(3)*> undef, i32 addrspace(3)* %t3, i32 0
call void @extern_vec_pointers_func(<16 x i32 addrspace(3)*> %t4)
ret void
}
```
Output:
```
define void @insertelem_after_gep(<16 x i32>* %t0) {
%t3 = getelementptr inbounds <16 x i32>, <16 x i32>* %t0, i64 0, i64 0
%t4 = insertelement <16 x i32 addrspace(3)*> undef, i32 addrspace(3)* %t3, i32 0
call void @my_extern_func(<16 x i32 addrspace(3)*> %t4)
ret void
}
```
Which although causes no complaints when produced, isn't valid IR as the insertelement use of the %t3 GEP expects an address space.
```
opt: /tmp/bad.ll:52:73: error: '%t3' defined with type 'i32*' but expected 'i32 addrspace(3)*'
%t4 = insertelement <16 x i32 addrspace(3)*> undef, i32 addrspace(3)* %t3, i32 0
```
I've fixed this by adding an addrspacecast after the GEP in the InstCombine pass, and including a check for this type mismatch to the verifier.
Reviewers: spatel, lebedev.ri
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D52294
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@343956 91177308-0d34-0410-b5e6-96231b3b80d8
DWARF v5 introduces DW_AT_call_all_calls, a subprogram attribute which
indicates that all calls (both regular and tail) within the subprogram
have call site entries. The information within these call site entries
can be used by a debugger to populate backtraces with synthetic tail
call frames.
Tail calling frames go missing in backtraces because the frame of the
caller is reused by the callee. Call site entries allow a debugger to
reconstruct a sequence of (tail) calls which led from one function to
another. This improves backtrace quality. There are limitations: tail
recursion isn't handled, variables within synthetic frames may not
survive to be inspected, etc. This approach is not novel, see:
https://gcc.gnu.org/wiki/summit2010?action=AttachFile&do=get&target=jelinek.pdf
This patch adds an IR-level flag (DIFlagAllCallsDescribed) which lowers
to DW_AT_call_all_calls. It adds the minimal amount of DWARF generation
support needed to emit standards-compliant call site entries. For easier
deployment, when the debugger tuning is LLDB, the DWARF requirement is
adjusted to v4.
Testing: Apart from check-{llvm, clang}, I built a stage2 RelWithDebInfo
clang binary. Its dSYM passed verification and grew by 1.4% compared to
the baseline. 151,879 call site entries were added.
rdar://42001377
Differential Revision: https://reviews.llvm.org/D49887
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@343883 91177308-0d34-0410-b5e6-96231b3b80d8
Summary: Add function name when verification fails as an initial breadcrumb for debugging.
Patch by David Callahan.
Reviewers: mehdi_amini, modocache
Reviewed By: modocache
Subscribers: llvm-commits, modocache
Differential Revision: https://reviews.llvm.org/D51386
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@341974 91177308-0d34-0410-b5e6-96231b3b80d8
This patch removes addBlockByrefAddress(), it is dead code as far as
clang is concerned: Every byref block capture is emitted with a
complex expression that is equivalent to what this function does.
rdar://problem/31629055
Differential Revision: https://reviews.llvm.org/D51763
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@341737 91177308-0d34-0410-b5e6-96231b3b80d8
Load Hardening.
Wires up the existing pass to work with a proper IR attribute rather
than just a hidden/internal flag. The internal flag continues to work
for now, but I'll likely remove it soon.
Most of the churn here is adding the IR attribute. I talked about this
Kristof Beyls and he seemed at least initially OK with this direction.
The idea of using a full attribute here is that we *do* expect at least
some forms of this for other architectures. There isn't anything
*inherently* x86-specific about this technique, just that we only have
an implementation for x86 at the moment.
While we could potentially expose this as a Clang-level attribute as
well, that seems like a good question to defer for the moment as it
isn't 100% clear whether that or some other programmer interface (or
both?) would be best. We'll defer the programmer interface side of this
for now, but at least get to the point where the feature can be enabled
without relying on implementation details.
This also allows us to do something that was really hard before: we can
enable *just* the indirect call retpolines when using SLH. For x86, we
don't have any other way to mitigate indirect calls. Other architectures
may take a different approach of course, and none of this is surfaced to
user-level flags.
Differential Revision: https://reviews.llvm.org/D51157
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@341363 91177308-0d34-0410-b5e6-96231b3b80d8
In the past, DbgInfoIntrinsic has a strong assumption that these
intrinsics all have variables and expressions attached to them.
However, it is too strong to derive the class for other debug entities.
Now, it has problems for debug labels.
In order to make DbgInfoIntrinsic as a base class for 'debug info', I
create a class for 'variable debug info', DbgVariableIntrinsic.
DbgDeclareInst, DbgAddrIntrinsic, and DbgValueInst will be derived from it.
Differential Revision: https://reviews.llvm.org/D50220
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@338984 91177308-0d34-0410-b5e6-96231b3b80d8
It's a bit neater to write T.isIntOrPtrTy() over `T.isIntegerTy() ||
T.isPointerTy()`.
I used Python's re.sub with this regex to update users:
r'([\w.\->()]+)isIntegerTy\(\)\s*\|\|\s*\1isPointerTy\(\)'
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@336462 91177308-0d34-0410-b5e6-96231b3b80d8
=== Generating the CG Profile ===
The CGProfile module pass simply gets the block profile count for each BB and scans for call instructions. For each call instruction it adds an edge from the current function to the called function with the current BB block profile count as the weight.
After scanning all the functions, it generates an appending module flag containing the data. The format looks like:
```
!llvm.module.flags = !{!0}
!0 = !{i32 5, !"CG Profile", !1}
!1 = !{!2, !3, !4} ; List of edges
!2 = !{void ()* @a, void ()* @b, i64 32} ; Edge from a to b with a weight of 32
!3 = !{void (i1)* @freq, void ()* @a, i64 11}
!4 = !{void (i1)* @freq, void ()* @b, i64 20}
```
Differential Revision: https://reviews.llvm.org/D48105
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@335794 91177308-0d34-0410-b5e6-96231b3b80d8
This is the first pass in the main pipeline to use the legacy PM's
ability to run function analyses "on demand". Unfortunately, it turns
out there are bugs in that somewhat-hacky approach. At the very least,
it leaks memory and doesn't support -debug-pass=Structure. Unclear if
there are larger issues or not, but this should get the sanitizer bots
back to green by fixing the memory leaks.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@335320 91177308-0d34-0410-b5e6-96231b3b80d8
This patch adds support for generating a call graph profile from Branch Frequency Info.
The CGProfile module pass simply gets the block profile count for each BB and scans for call instructions. For each call instruction it adds an edge from the current function to the called function with the current BB block profile count as the weight.
After scanning all the functions, it generates an appending module flag containing the data. The format looks like:
!llvm.module.flags = !{!0}
!0 = !{i32 5, !"CG Profile", !1}
!1 = !{!2, !3, !4} ; List of edges
!2 = !{void ()* @a, void ()* @b, i64 32} ; Edge from a to b with a weight of 32
!3 = !{void (i1)* @freq, void ()* @a, i64 11}
!4 = !{void (i1)* @freq, void ()* @b, i64 20}
Differential Revision: https://reviews.llvm.org/D48105
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@335306 91177308-0d34-0410-b5e6-96231b3b80d8
In order to set breakpoints on labels and list source code around
labels, we need collect debug information for labels, i.e., label
name, the function label belong, line number in the file, and the
address label located. In order to keep these information in LLVM
IR and to allow backend to generate debug information correctly.
We create a new kind of metadata for labels, DILabel. The format
of DILabel is
!DILabel(scope: !1, name: "foo", file: !2, line: 3)
We hope to keep debug information as much as possible even the
code is optimized. So, we create a new kind of intrinsic for label
metadata to avoid the metadata is eliminated with basic block.
The intrinsic will keep existing if we keep it from optimized out.
The format of the intrinsic is
llvm.dbg.label(metadata !1)
It has only one argument, that is the DILabel metadata. The
intrinsic will follow the label immediately. Backend could get the
label metadata through the intrinsic's parameter.
We also create DIBuilder API for labels to be used by Frontend.
Frontend could use createLabel() to allocate DILabel objects, and use
insertLabel() to insert llvm.dbg.label intrinsic in LLVM IR.
Differential Revision: https://reviews.llvm.org/D45024
Patch by Hsiangkai Wang.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@331841 91177308-0d34-0410-b5e6-96231b3b80d8
We've been running doxygen with the autobrief option for a couple of
years now. This makes the \brief markers into our comments
redundant. Since they are a visual distraction and we don't want to
encourage more \brief markers in new code either, this patch removes
them all.
Patch produced by
for i in $(git grep -l '\\brief'); do perl -pi -e 's/\\brief //g' $i & done
Differential Revision: https://reviews.llvm.org/D46290
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@331272 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
The verification rules for the intrinsics for atomic memcpy, atomic memmove,
and atomic memset are basically code clones. This change merges their verification
rules into a single block to remove duplication.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@329753 91177308-0d34-0410-b5e6-96231b3b80d8
r327219 added wrappers to std::sort which randomly shuffle the container before
sorting. This will help in uncovering non-determinism caused due to undefined
sorting order of objects having the same key.
To make use of that infrastructure we need to invoke llvm::sort instead of
std::sort.
Note: This patch is one of a series of patches to replace *all* std::sort to
llvm::sort. Refer D44363 for a list of all the required patches.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@329353 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Introduce the ShadowCallStack function attribute. It's added to
functions compiled with -fsanitize=shadow-call-stack in order to mark
functions to be instrumented by a ShadowCallStack pass to be submitted
in a separate change.
Reviewers: pcc, kcc, kubamracek
Reviewed By: pcc, kcc
Subscribers: cryptoad, mehdi_amini, javed.absar, llvm-commits, kcc
Differential Revision: https://reviews.llvm.org/D44800
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@329108 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
When building with libFuzzer, converting control flow to selects or
obscuring the original operands of CMPs reduces the effectiveness of
libFuzzer's heuristics.
This patch provides an attribute to disable or modify certain optimizations
for optimal fuzzing signal.
Provides a less aggressive alternative to https://reviews.llvm.org/D44057.
Reviewers: vitalybuka, davide, arsenm, hfinkel
Reviewed By: vitalybuka
Subscribers: junbuml, mehdi_amini, wdng, javed.absar, hiraditya, llvm-commits, kcc
Differential Revision: https://reviews.llvm.org/D44232
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@328214 91177308-0d34-0410-b5e6-96231b3b80d8
X86 Supports Indirect Branch Tracking (IBT) as part of Control-Flow Enforcement Technology (CET).
IBT instruments ENDBR instructions used to specify valid targets of indirect call / jmp.
The `nocf_check` attribute has two roles in the context of X86 IBT technology:
1. Appertains to a function - do not add ENDBR instruction at the beginning of the function.
2. Appertains to a function pointer - do not track the target function of this pointer by adding nocf_check prefix to the indirect-call instruction.
This patch implements `nocf_check` context for Indirect Branch Tracking.
It also auto generates `nocf_check` prefixes before indirect branchs to jump tables that are guarded by range checks.
Differential Revision: https://reviews.llvm.org/D41879
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@327767 91177308-0d34-0410-b5e6-96231b3b80d8
The retpoline mitigation for variant 2 of CVE-2017-5715 inhibits the
branch predictor, and as a result it can lead to a measurable loss of
performance. We can reduce the performance impact of retpolined virtual
calls by replacing them with a special construct known as a branch
funnel, which is an instruction sequence that implements virtual calls
to a set of known targets using a binary tree of direct branches. This
allows the processor to speculately execute valid implementations of the
virtual function without allowing for speculative execution of of calls
to arbitrary addresses.
This patch extends the whole-program devirtualization pass to replace
certain virtual calls with calls to branch funnels, which are
represented using a new llvm.icall.jumptable intrinsic. It also extends
the LowerTypeTests pass to recognize the new intrinsic, generate code
for the branch funnels (x86_64 only for now) and lay out virtual tables
as required for each branch funnel.
The implementation supports full LTO as well as ThinLTO, and extends the
ThinLTO summary format used for whole-program devirtualization to
support branch funnels.
For more details see RFC:
http://lists.llvm.org/pipermail/llvm-dev/2018-January/120672.html
Differential Revision: https://reviews.llvm.org/D42453
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@327163 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This patch adds verification logic for DICompositeType vectors, ensuring that they only have one element, and that element is of type subrange.
This patch complements https://reviews.llvm.org/D44048
Reviewers: aprantl
Reviewed By: aprantl
Subscribers: JDevlieghere, llvm-commits
Tags: #debug-info
Differential Revision: https://reviews.llvm.org/D44262
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@327048 91177308-0d34-0410-b5e6-96231b3b80d8
n Rust, an enum that carries data in the variants is, essentially, a
discriminated union. Furthermore, the Rust compiler will perform
space optimizations on such enums in some situations. Previously,
DWARF for these constructs was emitted using a hack (a magic field
name); but this approach stopped working when more space optimizations
were added in https://github.com/rust-lang/rust/pull/45225.
This patch changes LLVM to allow discriminated unions to be
represented in DWARF. It adds createDiscriminatedUnionType and
createDiscriminatedMemberType to DIBuilder and then arranges for this
to be emitted using DWARF's DW_TAG_variant_part and DW_TAG_variant.
Note that DWARF requires that a discriminated union be represented as
a structure with a variant part. However, as Rust only needs to emit
pure discriminated unions, this is what I chose to expose on
DIBuilder.
Patch by Tom Tromey!
Differential Revision: https://reviews.llvm.org/D42082
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@324426 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This change is step two in the series of changes to remove alignment argument from
memcpy/memmove/memset in favour of alignment attributes. Steps:
Step 1) Remove alignment parameter and create alignment parameter attributes for
memcpy/memmove/memset. ( rL322965 )
Step 2) Expand the IRBuilder API to allow creation of memcpy/memmove with differing
source and dest alignments.
Step 3) Update Clang to use the new IRBuilder API.
Step 4) Update Polly to use the new IRBuilder API.
Step 5) Update LLVM passes that create memcpy/memmove calls to use the new IRBuilder API,
and those that use use MemIntrinsicInst::[get|set]Alignment() to use
getDestAlignment() and getSourceAlignment() instead.
Step 6) Remove the single-alignment IRBuilder API for memcpy/memmove, and the
MemIntrinsicInst::[get|set]Alignment() methods.
Reference
http://lists.llvm.org/pipermail/llvm-dev/2015-August/089384.htmlhttp://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20151109/312083.html
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@323597 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This patch extends the DISubrange 'count' field to take either a
(signed) constant integer value or a reference to a DILocalVariable
or DIGlobalVariable.
This is patch [1/3] in a series to extend LLVM's DISubrange Metadata
node to support debugging of C99 variable length arrays and vectors with
runtime length like the Scalable Vector Extension for AArch64. It is
also a first step towards representing more complex cases like arrays
in Fortran.
Reviewers: echristo, pcc, aprantl, dexonsmith, clayborg, kristof.beyls, dblaikie
Reviewed By: aprantl
Subscribers: rnk, probinson, fhahn, aemerson, rengolin, JDevlieghere, llvm-commits
Differential Revision: https://reviews.llvm.org/D41695
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@323313 91177308-0d34-0410-b5e6-96231b3b80d8
Normally when llvm-as sees only debug info errors in LLVM assembly, it simply
drops the debug info and outputs a valid LLVM bitcode and returns 0.
There is a bug in LLVM verifier which incorrectly treats a debug info error
as non-debug info error, which causes llvm-as returns 1 even though llvm-as
can drop the invalid debug info and outputs a valid LLVM bitcode.
This patch fixes that.
Differential Revision: https://reviews.llvm.org/D42391
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@323216 91177308-0d34-0410-b5e6-96231b3b80d8
This is similar to r322317, but for visibility. It is not as neat
because we have to special case extern_weak.
The idea is the same as the previous change, make the transition to
explicit dso_local easier for the frontends. With this they only have
to add dso_local to symbols where we need some external information to
decide if it is dso_local (like it being part of an ELF executable).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@322806 91177308-0d34-0410-b5e6-96231b3b80d8
While updating clang tests for having clang set dso_local I noticed
that:
- There are *a lot* of tests to update.
- Many of the updates are redundant.
They are redundant because a GV is "obviously dso_local". This patch
starts formalizing that a bit by requiring that internal and private
GVs be dso_local too. Since they all are, we don't have to print
dso_local to the textual representation, making it a bit more compact
and easier to read.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@322317 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This pass synthesizes function entry counts by traversing the callgraph
and using the relative block frequencies of the callsites. The intended
use of these counts is in inlining to determine hot/cold callsites in
the absence of profile information.
The pass is split into two files with the code that propagates the
counts in a callgraph in a Utils file. I plan to add support for
propagation in the thinlto link phase and the propagation code will be
shared and hence this split. I did not add support to the old PM since
hot callsite determination in inlining is not possible in old PM
(although we could use hot callee heuristic with synthetic counts in the
old PM it is not worth the effort tuning it)
Reviewers: davidxl, silvas
Subscribers: mgorny, mehdi_amini, llvm-commits
Differential Revision: https://reviews.llvm.org/D41604
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@322110 91177308-0d34-0410-b5e6-96231b3b80d8
This implements the DWARF 5 feature described at
http://www.dwarfstd.org/ShowIssue.php?issue=141215.1
This allows a consumer to understand whether a composite data type is
trivially copyable and thus should be passed by value instead of by
reference. The canonical example is being able to distinguish the
following two types:
// S is not trivially copyable because of the explicit destructor.
struct S {
~S() {}
};
// T is a POD type.
struct T {
~T() = default;
};
This patch adds two new (DI)flags to LLVM metadata: TypePassByValue
and TypePassByReference.
<rdar://problem/36034922>
Differential Revision: https://reviews.llvm.org/D41743
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@321844 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This is LLVM instrumentation for the new HWASan tool. It is basically
a stripped down copy of ASan at this point, w/o stack or global
support. Instrumenation adds a global constructor + runtime callbacks
for every load and store.
HWASan comes with its own IR attribute.
A brief design document can be found in
clang/docs/HardwareAssistedAddressSanitizerDesign.rst (submitted earlier).
Reviewers: kcc, pcc, alekseyshl
Subscribers: srhines, mehdi_amini, mgorny, javed.absar, eraman, llvm-commits, hiraditya
Differential Revision: https://reviews.llvm.org/D40932
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@320217 91177308-0d34-0410-b5e6-96231b3b80d8
This cl::opt has been dead for a while. It's no longer possible to run
the verifier without also verifying debug info.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@317288 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
For reference, see: http://lists.llvm.org/pipermail/llvm-dev/2017-August/116589.html
This patch fleshes out the instruction class hierarchy with respect to atomic and
non-atomic memory intrinsics. With this change, the relevant part of the class
hierarchy becomes:
IntrinsicInst
-> MemIntrinsicBase (methods-only class)
-> MemIntrinsic (non-atomic intrinsics)
-> MemSetInst
-> MemTransferInst
-> MemCpyInst
-> MemMoveInst
-> AtomicMemIntrinsic (atomic intrinsics)
-> AtomicMemSetInst
-> AtomicMemTransferInst
-> AtomicMemCpyInst
-> AtomicMemMoveInst
-> AnyMemIntrinsic (both atomicities)
-> AnyMemSetInst
-> AnyMemTransferInst
-> AnyMemCpyInst
-> AnyMemMoveInst
This involves some class renaming:
ElementUnorderedAtomicMemCpyInst -> AtomicMemCpyInst
ElementUnorderedAtomicMemMoveInst -> AtomicMemMoveInst
ElementUnorderedAtomicMemSetInst -> AtomicMemSetInst
A script for doing this renaming in downstream trees is included below.
An example of where the Any* classes should be used in LLVM is when reasoning
about the effects of an instruction (ex: aliasing).
---
Script for renaming AtomicMem* classes:
PREFIXES="[<,([:space:]]"
CLASSES="MemIntrinsic|MemTransferInst|MemSetInst|MemMoveInst|MemCpyInst"
SUFFIXES="[;)>,[:space:]]"
REGEX="(${PREFIXES})ElementUnorderedAtomic(${CLASSES})(${SUFFIXES})"
REGEX2="visitElementUnorderedAtomic(${CLASSES})"
FILES=$( grep -E "(${REGEX}|${REGEX2})" -r . | tr ':' ' ' | awk '{print $1}' | sort | uniq )
SED_SCRIPT="s~${REGEX}~\1Atomic\2\3~g"
SED_SCRIPT2="s~${REGEX2}~visitAtomic\1~g"
for f in $FILES; do
echo "Processing: $f"
sed -i ".bak" -E "${SED_SCRIPT};${SED_SCRIPT2};${EA_SED_SCRIPT};${EA_SED_SCRIPT2}" $f
done
Reviewers: sanjoy, deadalnix, apilipenko, anna, skatkov, mkazantsev
Reviewed By: sanjoy
Subscribers: hfinkel, jholewinski, arsenm, sdardis, nhaehnle, JDevlieghere, javed.absar, llvm-commits
Differential Revision: https://reviews.llvm.org/D38419
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@316950 91177308-0d34-0410-b5e6-96231b3b80d8
Currently we do not represent runtime preemption in the IR, which has several
drawbacks:
1) The semantics of GlobalValues differ depending on the object file format
you are targeting (as well as the relocation-model and -fPIE value).
2) We have no way of disabling inlining of run time interposable functions,
since in the IR we only know if a function is link-time interposable.
Because of this llvm cannot support elf-interposition semantics.
3) In LTO builds of executables we will have extra knowledge that a symbol
resolved to a local definition and can't be preemptable, but have no way to
propagate that knowledge through the compiler.
This patch adds preemptability specifiers to the IR with the following meaning:
dso_local --> means the compiler may assume the symbol will resolve to a
definition within the current linkage unit and the symbol may be accessed
directly even if the definition is not within this compilation unit.
dso_preemptable --> means that the compiler must assume the GlobalValue may be
replaced with a definition from outside the current linkage unit at runtime.
To ease transitioning dso_preemptable is treated as a 'default' in that
low-level codegen will still do the same checks it did previously to see if a
symbol should be accessed indirectly. Eventually when IR producers emit the
specifiers on all Globalvalues we can change dso_preemptable to mean 'always
access indirectly', and remove the current logic.
Differential Revision: https://reviews.llvm.org/D20217
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@316668 91177308-0d34-0410-b5e6-96231b3b80d8
When more than one Module is imported into the same context, such as during
an LTO build before linking the modules, ODR type uniquing may cause types
to point to a different CU. This check does not make sense in this case.
This fixes the error reported in PR34944.
https://bugs.llvm.org/show_bug.cgi?id=34944
rdar://problem/34940685
This reapplies a cleaner implementation of r316049.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@316052 91177308-0d34-0410-b5e6-96231b3b80d8
Ewan Crawford