A constructor needs to know whether or not it is most derived in order
to determine if it is responsible for virtual bases. Delegating
constructors assumed they were most derived.
llvm-svn: 269465
Clang creates implicit move constructor/assign operator in all cases if
there is std=c++11. But MSVC supports such generation starting from
version 1900 only. As result we have some binary incompatibility.
Differential Revision: http://reviews.llvm.org/D19156
Patch by Andrew V. Tischenko
llvm-svn: 269400
Bases can be zero-initialized: the storage is zero-initialized before
the base constructor is run.
The MS ABI has a quirk where base VBPtrs are not installed by the
base constructor but by the most derived class. In particular, they are
installed before the base constructor is run.
The derived constructor must be careful to zero-initialize only the bits
of the class which haven't already been populated by virtual base
pointers.
While we correctly avoided this scenario, we didn't handle the case
where the base class has virtual bases which have virtual bases.
llvm-svn: 269271
This patch implements __unaligned (MS extension) as a proper type qualifier
(before that, it was implemented as an ignored attribute).
It also fixes PR27367 and PR27666.
Differential Revision: http://reviews.llvm.org/D20103
llvm-svn: 269220
Summary:
For a static object with a nontrivial destructor, clang generates an
initializer function (__cxx_global_var_init) which registers that
object's destructor using __cxa_atexit. However some ABIs (ARM,
WebAssembly) use destructors that return 'this' instead of having void
return (which does not match the signature of function pointers passed
to __cxa_atexit). This results in undefined behavior when the destructors are
called. All the calling conventions I know of on ARM can tolerate this,
but WebAssembly requires the signatures of indirect calls to match the
called function.
This patch disables that direct registration of destructors for ABIs
that have this-returning destructors.
Subscribers: aemerson, jfb, cfe-commits, dschuff
Differential Revision: http://reviews.llvm.org/D19275
llvm-svn: 269085
This patch corresponds to reviews:
http://reviews.llvm.org/D15120http://reviews.llvm.org/D19125
It adds support for the __float128 keyword, literals and target feature to
enable it. Based on the latter of the two aforementioned reviews, this feature
is enabled on Linux on i386/X86 as well as SystemZ.
This is also the second attempt in commiting this feature. The first attempt
did not enable it on required platforms which caused failures when compiling
type_traits with -std=gnu++11.
If you see failures with compiling this header on your platform after this
commit, it is likely that your platform needs to have this feature enabled.
llvm-svn: 268898
This patch implements __unaligned (MS extension) as a proper type qualifier
(before that, it was implemented as an ignored attribute).
It also fixes PR27367.
Differential Revision: http://reviews.llvm.org/D19654
llvm-svn: 268727
If we are devirtualizing, then we want to compute the 'this' adjustment
of the devirtualized target, not the adjustment of the base's method
definition, which is usually zero.
Fixes PR27621
llvm-svn: 268418
r268261 made Clang "expand" more struct arguments on Windows. It removed
the check for 'RD->isCLike()', which was preventing us from attempting
to expand structs with reference type fields.
Our expansion code was attempting to load and pass each field of the
type in turn. We were accidentally doing one to many loads on reference
type fields.
On the function prologue side, we can use
EmitLValueForFieldInitialization, which obviously gets the address of
the field. On the call side, I tweaked EmitRValueForField directly,
since this is the only use of this method.
Fixes PR27607
llvm-svn: 268321
Before this change, we would pass all non-HFA record arguments on
Windows with byval. Byval often blocks optimizations and results in bad
code generation. Windows now uses the existing workaround that other
x86_32 platforms use.
I also expanded the workaround to handle C++ records with constructors
on Windows. On non-Windows platforms, we have to keep generating the
same LLVM IR prototypes if we want our bitcode to be ABI compatible.
Otherwise we will encounter mismatch issues like PR21573.
Essentially fixes PR27522 in Clang instead of LLVM.
Reviewers: hans
Differential Revision: http://reviews.llvm.org/D19756
llvm-svn: 268261
Slightly updated version, double-checked build and tests.
Improve implementation of MS pragmas that use stack + compatibility fixes.
This patch:
1. Changes implementation of #pragma vtordisp to use PragmaStack class
that other stack pragmas use;
2. Fixes "#pragma vtordisp()" behavior - it shouldn't affect the stack;
3. Supports "save-restore" of pragma stacks on enter / exit a C++ method
body, as MSVC does.
TODO:
1. Change implementation of #pragma pack to use the same approach;
2. Introduce diagnostics on popping named stack slots, as MSVC does.
Reviewers:
rnk, thakis
Differential revision: http://reviews.llvm.org/D19361
llvm-svn: 268029
mangled name if it happened to be declared in an 'extern "C++"' context. This
also causes us to use the '_ZL' mangling rather than the '_Z' mangling for
internal-linkage entities that are wrapped in a language linkage construct.
llvm-svn: 267969
It makes compiler-rt tests fail if the gold plugin is enabled.
Revert "Rework interface for bitset-using features to use a notion of LTO visibility."
Revert "Driver: only produce CFI -fvisibility= error when compiling."
Revert "clang/test/CodeGenCXX/cfi-blacklist.cpp: Exclude ms targets. They would be non-cfi."
llvm-svn: 267871
Rework implementation of several MS pragmas that use internal stack:
vtordisp, {bss|code|const|data}_seg.
This patch:
1. Makes #pragma vtordisp use PragmaStack class as *_seg pragmas do;
2. Fixes "#pragma vtordisp()" behavior: it shouldn't affect stack;
3. Saves/restores the stacks on enter/exit a C++ method body.
llvm-svn: 267866
Bitsets, and the compiler features they rely on (vtable opt, CFI),
only have visibility within the LTO'd part of the linkage unit. Therefore,
only enable these features for classes with hidden LTO visibility. This
notion is based on object file visibility or (on Windows)
dllimport/dllexport attributes.
We provide the [[clang::lto_visibility_public]] attribute to override the
compiler's LTO visibility inference in cases where the class is defined
in the non-LTO'd part of the linkage unit, or where the ABI supports
calling classes derived from abstract base classes with hidden visibility
in other linkage units (e.g. COM on Windows).
If the cross-DSO CFI mode is enabled, bitset checks are emitted even for
classes with public LTO visibility, as that mode uses a separate mechanism
to cause bitsets to be exported.
This mechanism replaces the whole-program-vtables blacklist, so remove the
-fwhole-program-vtables-blacklist flag.
Because __declspec(uuid()) now implies [[clang::lto_visibility_public]], the
support for the special attr:uuid blacklist entry is removed.
Differential Revision: http://reviews.llvm.org/D18635
llvm-svn: 267784
Make 'nodebug' on a global/static variable suppress all debug info
for the variable. Previously it would only suppress info for the
associated initializer function, if any.
Differential Revision: http://reviews.llvm.org/D19567
llvm-svn: 267746
LLVM stopped using MDString-based type references, and DIBuilder no
longer fills 'retainedTypes:' with every DICompositeType that has an
'identifier:' field. There are just minor changes to keep the same
behaviour in CFE.
Leaving 'retainedTypes:' unfilled has a dramatic impact on the output
order of the IR though. There are a huge number of testcase changes,
which were unfortunately not really scriptable.
llvm-svn: 267297
Since elements of most kinds of DICompositeType have back references,
most are involved in uniquing cycles. Except via the ODR 'identifier:'
field, which doesn't care about the storage type (see r266549),
they have no hope of being uniqued.
Distinct nodes are far more efficient, so use them for most kinds of
DICompositeType definitions (i.e., when DIType::isForwardDecl is false).
The exceptions:
- DW_TAG_array_type, since their elements never have back-references
and they never have ODR 'identifier:' fields;
- DW_TAG_enumeration_type when there is no ODR 'identifier:' field,
since their elements usually don't have back-references.
This breaks the last major uniquing cycle I'm aware of in the debug info
graph. The impact won't be enormous for C++ because references to
ODR-uniqued nodes still use string-based DITypeRefs; but this should
prevent a regression in C++ when we drop the string-based references.
This wouldn't have been reasonable until r266549, when composite types
stopped relying on being uniqued by structural equivalence to prevent
blow-ups at LTO time.
llvm-svn: 266556
Since this patch provided support for the __float128 type but disabled it
on all platforms by default, some platforms can't compile type_traits with
-std=gnu++11 since there is a specialization with __float128.
This reverts the patch until D19125 is approved (i.e. we know which platforms
need this support enabled).
llvm-svn: 266460
This patch implements __unaligned as a type qualifier; before that, it was
modeled as an attribute. Proper mangling of __unaligned is implemented as well.
Some OpenCL code/tests are tangenially affected, as they relied on existing
number and sizes of type qualifiers.
Differential Revision: http://reviews.llvm.org/D18596
llvm-svn: 266415
This patch corresponds to review:
http://reviews.llvm.org/D15120
It adds support for the __float128 keyword, literals and a target feature to
enable it. This support is disabled by default on all targets and any target
that has support for this type is free to add it.
Based on feedback that I've received from target maintainers, this appears to
be the right thing for most targets. I have not heard from the maintainers of
X86 which I believe supports this type. I will subsequently investigate the
impact of enabling this on X86.
llvm-svn: 266186
CodeGen-level implementation. Instead of adding an attribute to clang's
FunctionDecl, add the IR attribute directly. This means a module built with
this flag is now compatible with code built without it and vice versa.
This change also results in the 'noalias' attribute no longer being added to
calls to operator new in the IR; it's now only added to the declaration. It
also fixes a bug where we failed to add the attribute to the 'nothrow' versions
(because we didn't implicitly declare them, there was no good time to inject a
fake attribute).
llvm-svn: 265728
landing pads.
Previously, lifetime.end intrinsics were inserted only on normal control
flows. This prevented StackColoring from merging stack slots for objects
that were destroyed on the exception handling control flow since it
couldn't tell their lifetime ranges were disjoint. This patch fixes
code-gen to emit the intrinsic on both control flows.
rdar://problem/22181976
Differential Revision: http://reviews.llvm.org/D18196
llvm-svn: 265197
Alexey Bataev