This should be a NFC cleanup. It removes a unnecessary loop to get the underlying
decl, and add an assertion.
The underlying decl of a using-shadow decl is always the original declaration
has been brought into the scope, clang never builds a nested using-shadow
decl (see Sema::BuildUsingShadowDecl).
Reviewed By: sammccall
Differential Revision: https://reviews.llvm.org/D123422
This includes a fix for the libc++ issue I ran across with friend
declarations not properly being identified as overloads.
This reverts commit 45c07db31c.
This reverts commit a97899108e.
The patch caused some problems with the libc++ `__range_adaptor_closure`
that I haven't been able to figure out the cause of, so I am reverting
while I figure out whether this is a solvable problem/issue with the
CFE, or libc++ depending on an older 'incorrect' behavior.
This reverts commit 0c31da4838.
I've solved the issue with the PointerUnion by making the
`FunctionTemplateDecl` pointer be a NamedDecl, that could be a
`FunctionDecl` or `FunctionTemplateDecl` depending. This is enforced
with an assert.
This reverts commit 4b6c2cd647.
The patch caused numerous ARM 32 bit build failures, since we added a
5th item to the PointerUnion, and went over the 2-bits available in the
32 bit pointers.
As reported here: https://github.com/llvm/llvm-project/issues/44178
Concepts are not supposed to be instantiated until they are checked, so
this patch implements that and goes through significant amounts of work
to make sure we properly re-instantiate the concepts correctly.
Differential Revision: https://reviews.llvm.org/D119544
A record may have more than just FieldDecls in it. If so, then we're
likely to drop them if we only randomize the FieldDecls.
We need to be careful about anonymous structs/unions. Their fields are
made available in the RecordDecl as IndirectFieldDecls, which are listed
after the anonymous struct/union. The ordering doesn't appear to be
super important, however we place them unrandomized at the end of the
RecordDecl just in case. There's also the possiblity of
StaticAssertDecls. We also want those at the end.
All other non-FieldDecls we place at the top, just in case we get
something like:
struct foo {
enum e { BORK };
enum e a;
};
Link: https://github.com/KSPP/linux/issues/185
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D123958
In D123649, I got the formula for getFlexibleArrayInitChars slightly
wrong: the flexible array elements can be contained in the tail padding
of the struct. Fix the formula to account for that.
With the fixed formula, we run into another issue: in some cases, we
were emitting extra padding for flexible arrray initializers. Fix
CGExprConstant so it uses a packed struct when necessary, to avoid this
extra padding.
Differential Revision: https://reviews.llvm.org/D123826
Flexible array initialization is a C/C++ extension implemented in many
compilers to allow initializing the flexible array tail of a struct type
that contains a flexible array. In clang, this is currently restricted
to C. But this construct is used in the Microsoft SDK headers, so I'd
like to extend it to C++.
For now, this doesn't handle dynamic initialization; probably not hard
to implement, but it's extra code, and I don't think it's necessary for
the expected uses. And we explicitly fail out of constant evaluation.
I've added some additional code to assert that initializers have the
correct size, with or without flexible array init. This might catch
issues unrelated to flexible array init.
Differential Revision: https://reviews.llvm.org/D123649
The Randstruct feature is a compile-time hardening technique that
randomizes the field layout for designated structures of a code base.
Admittedly, this is mostly useful for closed-source releases of code,
since the randomization seed would need to be available for public and
open source applications.
Why implement it? This patch set enhances Clang’s feature parity with
that of GCC which already has the Randstruct feature. It's used by the
Linux kernel in certain structures to help thwart attacks that depend on
structure layouts in memory.
This patch set is a from-scratch reimplementation of the Randstruct
feature that was originally ported to GCC. The patches for the GCC
implementation can be found here:
https://www.openwall.com/lists/kernel-hardening/2017/04/06/14
Link: https://lists.llvm.org/pipermail/cfe-dev/2019-March/061607.html
Co-authored-by: Cole Nixon <nixontcole@gmail.com>
Co-authored-by: Connor Kuehl <cipkuehl@gmail.com>
Co-authored-by: James Foster <jafosterja@gmail.com>
Co-authored-by: Jeff Takahashi <jeffrey.takahashi@gmail.com>
Co-authored-by: Jordan Cantrell <jordan.cantrell@mail.com>
Co-authored-by: Nikk Forbus <nicholas.forbus@gmail.com>
Co-authored-by: Tim Pugh <nwtpugh@gmail.com>
Co-authored-by: Bill Wendling <isanbard@gmail.com>
Signed-off-by: Bill Wendling <isanbard@gmail.com>
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D121556
This reverts commit 3f0587d0c6.
Not all tests pass after a few rounds of fixes.
I spot one failure that std::shuffle (potentially different results with
different STL implementations) was misused and replaced it with llvm::shuffle,
but there appears to be another failure in a Windows build.
The latest failure is reported on https://reviews.llvm.org/D121556#3440383
The Randstruct feature is a compile-time hardening technique that
randomizes the field layout for designated structures of a code base.
Admittedly, this is mostly useful for closed-source releases of code,
since the randomization seed would need to be available for public and
open source applications.
Why implement it? This patch set enhances Clang’s feature parity with
that of GCC which already has the Randstruct feature. It's used by the
Linux kernel in certain structures to help thwart attacks that depend on
structure layouts in memory.
This patch set is a from-scratch reimplementation of the Randstruct
feature that was originally ported to GCC. The patches for the GCC
implementation can be found here:
https://www.openwall.com/lists/kernel-hardening/2017/04/06/14
Link: https://lists.llvm.org/pipermail/cfe-dev/2019-March/061607.html
Co-authored-by: Cole Nixon <nixontcole@gmail.com>
Co-authored-by: Connor Kuehl <cipkuehl@gmail.com>
Co-authored-by: James Foster <jafosterja@gmail.com>
Co-authored-by: Jeff Takahashi <jeffrey.takahashi@gmail.com>
Co-authored-by: Jordan Cantrell <jordan.cantrell@mail.com>
Co-authored-by: Nikk Forbus <nicholas.forbus@gmail.com>
Co-authored-by: Tim Pugh <nwtpugh@gmail.com>
Co-authored-by: Bill Wendling <isanbard@gmail.com>
Signed-off-by: Bill Wendling <isanbard@gmail.com>
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D121556
At present, we are generating wrong code for C++20 modules entities which
should have internal linkage. This is because we are assigning
'ModuleInternalLinkage' unconditionally to such entities. However this mode
is only applicable to the modules-ts.
This change makes the special linkage mode conditional on fmodules-ts and
adds a unit test to verify that we generate the correct linkage.
Currently, static variables and functions in module purview are emitted into
object files as external. On some platforms, lambdas are emitted as global
weak defintions (on Windows this causes a mangler crash).
Differential Revision: https://reviews.llvm.org/D122413
Implement a demangleable strong ownership symbol mangling.
* The original module symbol mangling scheme turned out to be
undemangleable.
* The hoped-for C++17 compatibility of weak ownership turns out to be
fragile
* C++20 now has better ways of controlling C++17 compatibility
The issue is captured on the ABI list at:
https://github.com/itanium-cxx-abi/cxx-abi/issues/134
GCC implements this new mangling.
The old mangling is unceremoniously dropped. No backwards
compatibility, no deprectated old-mangling flag. It was always
labelled experimental. (Old and new manglings cannot be confused.)
Reviewed By: dblaikie
Differential Revision: https://reviews.llvm.org/D122256
This is the first in a series of patches that introduce C++20 importable
header units.
These differ from clang header modules in that:
(a) they are identifiable by an internal name
(b) they represent the top level source for a single header - although
that might include or import other headers.
We name importable header units with the path by which they are specified
(although that need not be the absolute path for the file).
So "foo/bar.h" would have a name "foo/bar.h". Header units are made a
separate module type so that we can deal with diagnosing places where they
are permitted but a named module is not.
Differential Revision: https://reviews.llvm.org/D121095
specialization
Before the patch, the compiler would crash for the test due to
inconsistent linkage.
This patch tries to avoid it by make the linkage consistent for template
and its specialization. After the patch, the behavior of compiler would
be partially correct for the case.
The correct one is:
```
export template<class T>
void f() {}
template<>
void f<int>() {}
```
In this case, the linkage for both declaration should be external (the
wording I get by consulting in WG21 is "the linkage for name f should be
external").
And for the case:
```
template<class T>
void f() {}
export template<>
void f<int>() {}
```
Compiler should reject it. This isn't done now. After all, this patch would
stop a crash.
Reviewed By: iains, aaron.ballman, dblaikie
Differential Revision: https://reviews.llvm.org/D120397
The existing module symbol mangling scheme turns out to be
undemangleable. It is also desirable to switch to the
strong-ownership model as the hoped-for C++17 compatibility turns out
to be fragile, and we also now have a better way of controlling that.
The issue is captured on the ABI list at:
https://github.com/itanium-cxx-abi/cxx-abi/issues/134
A document describing the issues and new mangling is at:
https://drive.google.com/file/d/1qQjqptzOFT_lfXH8L6-iD9nCRi34wjft/view
This patch is the code-generation part. I have a demangler too, but
that patch is based on some to-be-landed refactoring of the demangler.
The old mangling is unceremoniously dropped. No backwards
compatibility, no deprectated old-mangling flag. It was always
labelled experimental. (Old and new manglings cannot be confused.)
Reviewed By: ChuanqiXu
Differential Revision: https://reviews.llvm.org/D118352
This is an initial enabling patch for module partition support.
We add enumerations for partition interfaces/implementations.
This means that the module kind enumeration now occupies three
bits, so the AST streamer is adjusted for this. Adding one bit there
seems preferable to trying to overload the meanings of existing
kinds (and we will also want to add a C++20 header unit case later).
Differential Revision: https://reviews.llvm.org/D114714
For redeclaration chains we maintain an invariant of having only a
single definition in the chain. In a single translation unit we make
sure not to create duplicates. But modules are separate translation
units and they can contain definitions for the same symbol
independently. When we load such modules together, we need to demote
duplicate definitions to keep the AST invariants.
Some AST clients are interested in distinguishing
declaration-that-was-demoted-from-definition and
declaration-that-was-never-a-definition. For that purpose introducing
`IsThisDeclarationADemotedDefinition`. No functional change intended.
rdar://84677782
Differential Revision: https://reviews.llvm.org/D118855
NamespaceDecls are NamedDecls, so NSD can never be non-null in the
else branch. Add a comment about this whole ModuleInternal linkage
concept going away when p1815 is implemented.
Reviewed By: bruno
Differential Revision: https://reviews.llvm.org/D118704
This patch changes the special-case handling of visibility when
compiling for an OpenMP target offloading device. This was orignally
added as a precaution against the bug encountered in PR41826 when
symbols in the device were being preempted by shared library symbols.
This should instead be done by making the visibility protected by default.
With protected visibility we are asserting that the symbols on the device
will never be preempted or preempt another symbol pending a shared library
load.
Reviewed By: JonChesterfield
Differential Revision: https://reviews.llvm.org/D117806
This patch changes the visiblity of variables declared within a declare
target directive. Variable declarations within a declare target
directive need to be externally visible to the plugin for initialization
or reading. Previously this would cause runtime errors where the named
global could not be found because it was not included in the symbol
table.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D117362
This patch changes the visiblity of variables declared within a declare
target directive. Variable declarations within a declare target
directive need to be externally visible to the plugin for initialization
or reading. Previously this would cause runtime errors where the named
global could not be found because it was not included in the symbol
table.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D117362
This avoids an unnecessary copy required by 'return OS.str()', allowing
instead for NRVO or implicit move. The .str() call (which flushes the
stream) is no longer required since 65b13610a5,
which made raw_string_ostream unbuffered by default.
Differential Revision: https://reviews.llvm.org/D115374
According to [basic.namespace.general]/p2, a namespace declaration
shouldn't have a module linkage.
> A namespace is never attached to a named module and never has a name
> with module linkage.
Without this patch, the compiler would crash for the test in assertion
enabled build due to inconsistent linkage for redeclaration for
namespaces.
Reviewed by: rsmith
Differential Revision: https://reviews.llvm.org/D115132
See discussion in D51650, this change was a little aggressive in an
error while doing a 'while we were here', so this removes that error
condition, as it is apparently useful.
This reverts commit bb4934601d.
As discussed here: https://lwn.net/Articles/691932/
GCC6.0 adds target_clones multiversioning. This functionality is
an odd cross between the cpu_dispatch and 'target' MV, but is compatible
with neither.
This attribute allows you to list all options, then emits a separately
optimized version of each function per-option (similar to the
cpu_specific attribute). It automatically generates a resolver, just
like the other two.
The mangling however, is... ODD to say the least. The mangling format
is:
<normal_mangling>.<option string>.<option ordinal>.
Differential Revision:https://reviews.llvm.org/D51650
This used to span just the `[[enum foo]] : bar;` in the absence of a
body. This patch expands the range to cover the base specifier, so that the
various consumers can detect the full range of the decl.
Differential Revision: https://reviews.llvm.org/D111259
non-Darwin ObjC runtimes:
- Use the same logic the Darwin runtime does for inferring that a
receiver is non-null and therefore doesn't require null checks.
Previously we weren't skipping these for non-super dispatch.
- Emit a null check when there's a consumed parameter so that we can
destroy the argument if the call doesn't happen. This mostly
involves extracting some common logic from the Darwin-runtime code.
- Generate a zero aggregate by zeroing the same memory that was used
in the method call instead of zeroing separate memory and then
merging them with a phi. This uses less memory and avoids unnecessary
copies.
- Emit zero initialization, and generate zero values in phis, using
the proper zero-value routines instead of assuming that the zero
value of the result type has a bitwise-zero representation.
declaration.
Names starting with an underscore are reserved at the global scope, so
cannot be used as the name of an extern "C" symbol in any scope because
such usages conflict with a name at global scope.
Also do not warn on `#define _foo` or `#undef _foo`.
Only global scope names starting with _[a-z] are reserved, not the use
of such an identifier in any other context.
Per the GCC info page:
If the function is declared 'extern', then this definition of the
function is used only for inlining. In no case is the function
compiled as a standalone function, not even if you take its address
explicitly. Such an address becomes an external reference, as if
you had only declared the function, and had not defined it.
Respect that behavior for inline builtins: keep the original definition, and
generate a copy of the declaration suffixed by '.inline' that's only referenced
in direct call.
This fixes holes in c3717b6858.
Differential Revision: https://reviews.llvm.org/D111009
Require it to be always_inline, to more closely match how _FORITFY_SOURCE
behaves.
This avoids generation of `.inline` suffixed functions - these should always be
inlined.
Clang currently picks the second tentative definition when
VarDecl::getActingDefinition is called.
This can lead to attributes being dropped if they are attached to
tentative definitions that appear after the second one. This is
because VarDecl::getActingDefinition loops through VarDecl::redecls
assuming that the last tentative definition is the last element in the
iterator. However, it is the second element that would be the last
tentative definition.
This changeset modifies getActingDefinition to iterate through the
declaration chain in reverse, so that it can immediately return when
it encounters a tentative definition.
Originally the unit test for this changeset did not have a -triple
flag for the clang invocation, leading to this test being broken on
MacOS, since Mach-O does not support the section attribute.
Differential Revision: https://reviews.llvm.org/D99732
Clang currently picks the second tentative definition when
VarDecl::getActingDefinition is called.
This can lead to attributes being dropped if they are attached to
tentative definitions that appear after the second one. This is
because VarDecl::getActingDefinition loops through VarDecl::redecls
assuming that the last tentative definition is the last element in the
iterator. However, it is the second element that would be the last
tentative definition.
This changeset modifies getActingDefinition to iterate through the
declaration chain in reverse, so that it can immediately return when
it encounters a tentative definition.
Differential Revision: https://reviews.llvm.org/D99732
@kpn pointed out that the global variable initialization functions didn't
have the "strictfp" metadata set correctly, and @rjmccall said that there
was buggy code in SetFPModel and StartFunction, this patch is to solve
those problems. When Sema creates a FunctionDecl, it sets the
FunctionDeclBits.UsesFPIntrin to "true" if the lexical FP settings
(i.e. a combination of command line options and #pragma float_control
settings) correspond to ConstrainedFP mode. That bit is used when CodeGen
starts codegen for a llvm function, and it translates into the
"strictfp" function attribute. See bugs.llvm.org/show_bug.cgi?id=44571
Reviewed By: Aaron Ballman
Differential Revision: https://reviews.llvm.org/D102343
Original commit message:
[clang-repl] Implement partial translation units and error recovery.
https://reviews.llvm.org/D96033 contained a discussion regarding efficient
modeling of error recovery. @rjmccall has outlined the key ideas:
Conceptually, we can split the translation unit into a sequence of partial
translation units (PTUs). Every declaration will be associated with a unique PTU
that owns it.
The first key insight here is that the owning PTU isn't always the "active"
(most recent) PTU, and it isn't always the PTU that the declaration
"comes from". A new declaration (that isn't a redeclaration or specialization of
anything) does belong to the active PTU. A template specialization, however,
belongs to the most recent PTU of all the declarations in its signature - mostly
that means that it can be pulled into a more recent PTU by its template
arguments.
The second key insight is that processing a PTU might extend an earlier PTU.
Rolling back the later PTU shouldn't throw that extension away. For example, if
the second PTU defines a template, and the third PTU requires that template to
be instantiated at float, that template specialization is still part of the
second PTU. Similarly, if the fifth PTU uses an inline function belonging to the
fourth, that definition still belongs to the fourth. When we go to emit code in
a new PTU, we map each declaration we have to emit back to its owning PTU and
emit it in a new module for just the extensions to that PTU. We keep track of
all the modules we've emitted for a PTU so that we can unload them all if we
decide to roll it back.
Most declarations/definitions will only refer to entities from the same or
earlier PTUs. However, it is possible (primarily by defining a
previously-declared entity, but also through templates or ADL) for an entity
that belongs to one PTU to refer to something from a later PTU. We will have to
keep track of this and prevent unwinding to later PTU when we recognize it.
Fortunately, this should be very rare; and crucially, we don't have to do the
bookkeeping for this if we've only got one PTU, e.g. in normal compilation.
Otherwise, PTUs after the first just need to record enough metadata to be able
to revert any changes they've made to declarations belonging to earlier PTUs,
e.g. to redeclaration chains or template specialization lists.
It should even eventually be possible for PTUs to provide their own slab
allocators which can be thrown away as part of rolling back the PTU. We can
maintain a notion of the active allocator and allocate things like Stmt/Expr
nodes in it, temporarily changing it to the appropriate PTU whenever we go to do
something like instantiate a function template. More care will be required when
allocating declarations and types, though.
We would want the PTU to be efficiently recoverable from a Decl; I'm not sure
how best to do that. An easy option that would cover most declarations would be
to make multiple TranslationUnitDecls and parent the declarations appropriately,
but I don't think that's good enough for things like member function templates,
since an instantiation of that would still be parented by its original class.
Maybe we can work this into the DC chain somehow, like how lexical DCs are.
We add a different kind of translation unit `TU_Incremental` which is a
complete translation unit that we might nonetheless incrementally extend later.
Because it is complete (and we might want to generate code for it), we do
perform template instantiation, but because it might be extended later, we don't
warn if it declares or uses undefined internal-linkage symbols.
This patch teaches clang-repl how to recover from errors by disconnecting the
most recent PTU and update the primary PTU lookup tables. For instance:
```./clang-repl
clang-repl> int i = 12; error;
In file included from <<< inputs >>>:1:
input_line_0:1:13: error: C++ requires a type specifier for all declarations
int i = 12; error;
^
error: Parsing failed.
clang-repl> int i = 13; extern "C" int printf(const char*,...);
clang-repl> auto r1 = printf("i=%d\n", i);
i=13
clang-repl> quit
```
Differential revision: https://reviews.llvm.org/D104918
This reverts commit 6775fc6ffa.
It also reverts "[lldb] Fix compilation by adjusting to the new ASTContext signature."
This reverts commit 03a3f86071.
We see some failures on the lldb infrastructure, these changes might play a role
in it. Let's revert it now and see if the bots will become green.
Ref: https://reviews.llvm.org/D104918
https://reviews.llvm.org/D96033 contained a discussion regarding efficient
modeling of error recovery. @rjmccall has outlined the key ideas:
Conceptually, we can split the translation unit into a sequence of partial
translation units (PTUs). Every declaration will be associated with a unique PTU
that owns it.
The first key insight here is that the owning PTU isn't always the "active"
(most recent) PTU, and it isn't always the PTU that the declaration
"comes from". A new declaration (that isn't a redeclaration or specialization of
anything) does belong to the active PTU. A template specialization, however,
belongs to the most recent PTU of all the declarations in its signature - mostly
that means that it can be pulled into a more recent PTU by its template
arguments.
The second key insight is that processing a PTU might extend an earlier PTU.
Rolling back the later PTU shouldn't throw that extension away. For example, if
the second PTU defines a template, and the third PTU requires that template to
be instantiated at float, that template specialization is still part of the
second PTU. Similarly, if the fifth PTU uses an inline function belonging to the
fourth, that definition still belongs to the fourth. When we go to emit code in
a new PTU, we map each declaration we have to emit back to its owning PTU and
emit it in a new module for just the extensions to that PTU. We keep track of
all the modules we've emitted for a PTU so that we can unload them all if we
decide to roll it back.
Most declarations/definitions will only refer to entities from the same or
earlier PTUs. However, it is possible (primarily by defining a
previously-declared entity, but also through templates or ADL) for an entity
that belongs to one PTU to refer to something from a later PTU. We will have to
keep track of this and prevent unwinding to later PTU when we recognize it.
Fortunately, this should be very rare; and crucially, we don't have to do the
bookkeeping for this if we've only got one PTU, e.g. in normal compilation.
Otherwise, PTUs after the first just need to record enough metadata to be able
to revert any changes they've made to declarations belonging to earlier PTUs,
e.g. to redeclaration chains or template specialization lists.
It should even eventually be possible for PTUs to provide their own slab
allocators which can be thrown away as part of rolling back the PTU. We can
maintain a notion of the active allocator and allocate things like Stmt/Expr
nodes in it, temporarily changing it to the appropriate PTU whenever we go to do
something like instantiate a function template. More care will be required when
allocating declarations and types, though.
We would want the PTU to be efficiently recoverable from a Decl; I'm not sure
how best to do that. An easy option that would cover most declarations would be
to make multiple TranslationUnitDecls and parent the declarations appropriately,
but I don't think that's good enough for things like member function templates,
since an instantiation of that would still be parented by its original class.
Maybe we can work this into the DC chain somehow, like how lexical DCs are.
We add a different kind of translation unit `TU_Incremental` which is a
complete translation unit that we might nonetheless incrementally extend later.
Because it is complete (and we might want to generate code for it), we do
perform template instantiation, but because it might be extended later, we don't
warn if it declares or uses undefined internal-linkage symbols.
This patch teaches clang-repl how to recover from errors by disconnecting the
most recent PTU and update the primary PTU lookup tables. For instance:
```./clang-repl
clang-repl> int i = 12; error;
In file included from <<< inputs >>>:1:
input_line_0:1:13: error: C++ requires a type specifier for all declarations
int i = 12; error;
^
error: Parsing failed.
clang-repl> int i = 13; extern "C" int printf(const char*,...);
clang-repl> auto r1 = printf("i=%d\n", i);
i=13
clang-repl> quit
```
Differential revision: https://reviews.llvm.org/D104918
Named return of a variable with aligned attribute would
trip an assert in case alignment was dependent.
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
Reviewed By: rsmith
Differential Revision: https://reviews.llvm.org/D105380
Named return of a variable with aligned attribute would
trip an assert in case alignment was dependent.
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
Reviewed By: rsmith
Differential Revision: https://reviews.llvm.org/D105380
Haojian Wu