[WPD] Use new llvm.public.type.test intrinsic for potentially publicly visible classes

Turning on opaque pointers has uncovered an issue with WPD where we currently pattern match away `assume(type.t

[WPD] Use new llvm.public.type.test intrinsic for potentially publicly visible classes

Turning on opaque pointers has uncovered an issue with WPD where we currently pattern match away `assume(type.test)` in WPD so that a later LTT doesn't resolve the type test to undef and introduce an `assume(false)`. The pattern matching can fail in cases where we transform two `assume(type.test)`s into `assume(phi(type.test.1, type.test.2))`.

Currently we create `assume(type.test)` for all virtual calls that might be devirtualized. This is to support `-Wl,--lto-whole-program-visibility`.

To prevent this, all virtual calls that may not be in the same LTO module instead use a new `llvm.public.type.test` intrinsic in place of the `llvm.type.test`. Then when we know if `-Wl,--lto-whole-program-visibility` is passed or not, we can either replace all `llvm.public.type.test` with `llvm.type.test`, or replace all `llvm.public.type.test` with `true`. This prevents WPD from trying to pattern match away `assume(type.test)` for public virtual calls when failing the pattern matching will result in miscompiles.

Reviewed By: tejohnson

Differential Revision: https://reviews.llvm.org/D128955

show more ...

[IPO] Use default member initialization (NFC)

Identified with modernize-use-default-member-init.

Cleanup includes: Transforms/IPO

Preprocessor output diff: -238205 lines
Discourse thread: https://discourse.llvm.org/t/include-what-you-use-include-cleanup
Differential Revision: https://reviews.ll

Cleanup includes: Transforms/IPO

Preprocessor output diff: -238205 lines
Discourse thread: https://discourse.llvm.org/t/include-what-you-use-include-cleanup
Differential Revision: https://reviews.llvm.org/D122183

show more ...

[FunctionAttrs] Replace MemoryAccessKind with FMRB.

Update FunctionAttrs to use FunctionModRefBehavior instead
MemoryAccessKind.

This allows for adding support for inferring argmemonly and others,

[FunctionAttrs] Replace MemoryAccessKind with FMRB.

Update FunctionAttrs to use FunctionModRefBehavior instead
MemoryAccessKind.

This allows for adding support for inferring argmemonly and others,
see D121415.

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D121460

show more ...

[BitcodeWriter] Fix cases of some functions

`WriteIndexToFile` is used by external projects so I do not touch it.

[ThinLTO][MC] Use conditional assignments for promotion aliases

Inline assembly refererences to static functions with ThinLTO+CFI were
fixed in D104058 by creating aliases for promoted functions. Cr

[ThinLTO][MC] Use conditional assignments for promotion aliases

Inline assembly refererences to static functions with ThinLTO+CFI were
fixed in D104058 by creating aliases for promoted functions. Creating
the aliases unconditionally resulted in an unexpected size increase in
a Chrome helper binary:

https://bugs.chromium.org/p/chromium/issues/detail?id=1261715

This is caused by the compiler being unable to drop unused code now
referenced by the alias in module-level inline assembly. This change
adds a .set_conditional assembly extension, which emits an assignment
only if the target symbol is also emitted, avoiding phantom references
to functions that could have otherwise been dropped.

This is an alternative to the solution proposed in D112761.

Reviewed By: pcc, nickdesaulniers, MaskRay

Differential Revision: https://reviews.llvm.org/D113613

show more ...

[IR][NFC] Rename getBaseObject to getAliaseeObject

To better reflect the meaning of the now-disambiguated {GlobalValue,
GlobalAlias}::getBaseObject after breaking off GlobalIFunc::getResolverFunctio

[IR][NFC] Rename getBaseObject to getAliaseeObject

To better reflect the meaning of the now-disambiguated {GlobalValue,
GlobalAlias}::getBaseObject after breaking off GlobalIFunc::getResolverFunction
(D109792), the function is renamed to getAliaseeObject.

show more ...

[Transforms] Use make_early_inc_range (NFC)

[IPO] Use make_early_inc_range (NFC)

[NFC] Rename AttributeList::getParam/Ret/FnAttributes() -> get*Attributes()

This is more consistent with similar methods.

ThinLTO: Fix inline assembly references to static functions with CFI

Create an internal alias with the original name for static functions
that are renamed in promoteInternals to avoid breaking inlin

ThinLTO: Fix inline assembly references to static functions with CFI

Create an internal alias with the original name for static functions
that are renamed in promoteInternals to avoid breaking inline
assembly references to them.

Relands 700d07f8ce6f2879610fd6b6968b05c6f17bb915 with -msvc targets
fixed.

Link: https://github.com/ClangBuiltLinux/linux/issues/1354

Reviewed By: nickdesaulniers, pcc

Differential Revision: https://reviews.llvm.org/D104058

show more ...

Revert "ThinLTO: Fix inline assembly references to static functions with CFI"

This reverts commit 700d07f8ce6f2879610fd6b6968b05c6f17bb915.

Reverting due to a ThinLTO+CFI breakage on -msvc targets.

[ThinTLOBitcodeWriter] Fix unused variable warning (NFC)

ThinLTO: Fix inline assembly references to static functions with CFI

Create an internal alias with the original name for static functions
that are renamed in promoteInternals to avoid breaking inlin

ThinLTO: Fix inline assembly references to static functions with CFI

Create an internal alias with the original name for static functions
that are renamed in promoteInternals to avoid breaking inline
assembly references to them. This version uses module inline assembly
to avoid issues with LowerTypeTestsModule.

Relands commmit 8e3b5cb39eef462943ed7556469604ce25c07a1d with arch
specific tests fixed.

Link: https://github.com/ClangBuiltLinux/linux/issues/1354

Reviewed By: nickdesaulniers, pcc

Differential Revision: https://reviews.llvm.org/D104058

show more ...

Revert "ThinLTO: Fix inline assembly references to static functions with CFI"

This reverts commit 8e3b5cb39eef462943ed7556469604ce25c07a1d.

Reverting to investigate test failures.

ThinLTO: Fix inline assembly references to static functions with CFI

Create an internal alias with the original name for static functions
that are renamed in promoteInternals to avoid breaking inlin

ThinLTO: Fix inline assembly references to static functions with CFI

Create an internal alias with the original name for static functions
that are renamed in promoteInternals to avoid breaking inline
assembly references to them. This version uses module inline assembly
to avoid issues with LowerTypeTestsModule.

Link: https://github.com/ClangBuiltLinux/linux/issues/1354

Reviewed By: nickdesaulniers, pcc

Differential Revision: https://reviews.llvm.org/D104058

show more ...

Revert "ThinLTO: Fix inline assembly references to static functions with CFI"

This casues compiler crash: Assertion `materialized_use_empty() && "Uses remain when a value is destroyed!"'

This rever

Revert "ThinLTO: Fix inline assembly references to static functions with CFI"

This casues compiler crash: Assertion `materialized_use_empty() && "Uses remain when a value is destroyed!"'

This reverts commit e3d24b45b8f808ec66213e134c4ceda5202fbe31.

show more ...

ThinLTO: Fix inline assembly references to static functions with CFI

Create an internal alias with the original name for static functions
that are renamed in promoteInternals to avoid breaking inlin

ThinLTO: Fix inline assembly references to static functions with CFI

Create an internal alias with the original name for static functions
that are renamed in promoteInternals to avoid breaking inline
assembly references to them.

This relands commit 4474958d3a97dede2caa0920f7c4a4dc7aac57d3
with a fix to a use-of-uninitialized-value error that tripped
MemorySanitizer.

Link: https://github.com/ClangBuiltLinux/linux/issues/1354

Reviewed By: nickdesaulniers, pcc

Differential Revision: https://reviews.llvm.org/D104058

show more ...

Revert "ThinLTO: Fix inline assembly references to static functions with CFI"

This reverts commit 4474958d3a97dede2caa0920f7c4a4dc7aac57d3.

Breaks check-llvm on Mac.

ThinLTO: Fix inline assembly references to static functions with CFI

Create an internal alias with the original name for static functions
that are renamed in promoteInternals to avoid breaking inlin

ThinLTO: Fix inline assembly references to static functions with CFI

Create an internal alias with the original name for static functions
that are renamed in promoteInternals to avoid breaking inline
assembly references to them.

Link: https://github.com/ClangBuiltLinux/linux/issues/1354

Reviewed By: pcc

Differential Revision: https://reviews.llvm.org/D104058

show more ...

[ThinLTO] Copy UnnamedAddr when spliting module.

The unnamedaddr property of a function is lost when using
`-fwhole-program-vtables` and thinlto which causes size increase under linker's
safe icf mo

[ThinLTO] Copy UnnamedAddr when spliting module.

The unnamedaddr property of a function is lost when using
`-fwhole-program-vtables` and thinlto which causes size increase under linker's
safe icf mode.

The size increase of chrome on Linux when switching from all icf to safe icf
drops from 5 MB to 3 MB after this change, and from 6 MB to 4 MB on Windows.

There is a repro:
```
# a.h
struct A {
virtual int f();
virtual int g();
};

# a.cpp
#include "a.h"
int A::f() { return 10; }
int A::g() { return 10; }

# main.cpp
#include "a.h"

int g(A* a) {
return a->f();
}

int main(int argv, char** args) {
A a;
return g(&a);
}

$ clang++ -O2 -ffunction-sections -flto=thin -fwhole-program-vtables -fsplit-lto-unit -c main.cpp -o main.o && clang++ -Wl,--icf=safe -fuse-ld=lld -flto=thin main.o -o a.out && llvm-readobj -t a.out | grep -A 1 -e _ZN1A1fEv -e _ZN1A1gEv
Name: _ZN1A1fEv (480)
Value: 0x201830
--
Name: _ZN1A1gEv (490)
Value: 0x201840
```

Differential Revision: https://reviews.llvm.org/D100498

show more ...

[ThinLTO] Make cloneUsedGlobalVariables deterministic

Iterating on `SmallPtrSet<GlobalValue *, 8>` with more than 8 elements
is not deterministic. Use a SmallVector instead because `Used` is guarant

[ThinLTO] Make cloneUsedGlobalVariables deterministic

Iterating on `SmallPtrSet<GlobalValue *, 8>` with more than 8 elements
is not deterministic. Use a SmallVector instead because `Used` is guaranteed to contain unique elements.

While here, decrease inline element counts from 8 to 4. The number of
`llvm.used`/`llvm.compiler.used` elements is usually 0 or 1. For full
LTO/hybrid LTO, the number may be large, so we need to be careful.

According to tejohnson's analysis https://reviews.llvm.org/D97128#2582399 , 4 is
good for a large project with WholeProgramDevirt, when available_externally
vtables are placed in the llvm.compiler.used set.

Differential Revision: https://reviews.llvm.org/D97128

show more ...

[LTO] Fix cloning of llvm*.used when splitting module

Refines the fix in 3c4c205060c9398da705eb71b63ddd8a04999de9 to only
put globals whose defs were cloned into the split regular LTO module
on the

[LTO] Fix cloning of llvm*.used when splitting module

Refines the fix in 3c4c205060c9398da705eb71b63ddd8a04999de9 to only
put globals whose defs were cloned into the split regular LTO module
on the cloned llvm*.used globals. This avoids an issue where one of the
attached values was a local that was promoted in the original module
after the module was cloned. We only need to have the values defined in
the new module on those globals.

Fixes PR49251.

Differential Revision: https://reviews.llvm.org/D97013

show more ...

[WPD][lld] Test handling of vtable definition from shared libraries

Adds a lld test for a case that the handling added for dynamically
exported symbols in 1487747e990ce9f8851f3d92c3006a74134d7518 al

[WPD][lld] Test handling of vtable definition from shared libraries

Adds a lld test for a case that the handling added for dynamically
exported symbols in 1487747e990ce9f8851f3d92c3006a74134d7518 already
fixes. Because isExportDynamic returns true when the symbol is
SharedKind with default visibility, it will treat as dynamically
exported and block devirtualization when the definition of a vtable
comes from a shared library. This is desireable as it is dangerous to
devirtualize in that case, since there could be hidden overrides in the
shared library. Typically that happens when the shared library header
contains available externally definitions, which applications can
override. An example is std::error_category, which is overridden in LLVM
and causing failures after a self build with WPD enabled, because
libstdc++ contains hidden overrides of the virtual base class methods.

The regular LTO case in the new test already worked, but there are
2 fixes in this patch needed for the index-only case and the hybrid
LTO case. For the index-only case, WPD should not simply ignore
available externally vtables. A follow on fix will be made to clang to
emit type metadata for those vtables, which the new test is modeling.
For the hybrid case, we need to ensure when the module is split that any
llvm.*used globals are cloned to the regular LTO split module so
available externally vtable definitions are not prematurely deleted.

Another follow on fix will add the equivalent gold test, which requires
a small fix to the plugin to treat symbols in dynamic libraries the same
way lld already is.

Differential Revision: https://reviews.llvm.org/D96721

show more ...

[Transforms] Use llvm::append_range (NFC)