Summary:
The MS ABI convention is that the 'this' pointer on entry is the address
of the vfptr that was used to make the virtual method call. In other
words, the pointer on entry always points to the base subobject that
introduced the virtual method. Consider this hierarchy:
struct A { virtual void f() = 0; };
struct B { virtual void g() = 0; };
struct C : A, B {
void f() override;
void g() override;
};
On entry to C::g, [ER]CX will contain the address of C's B subobject,
and C::g will have to subtract sizeof(A) to recover a pointer to C.
Before this change, we applied this adjustment in the prologue and
stored the new value into the "this" local variable alloca used for
debug info. However, MSVC does not do this, presumably because it is
often profitable to fold the adjustment into later field accesses. This
creates a problem, because the debugger expects the variable to be
unadjusted. Unfortunately, CodeView doesn't have anything like DWARF
expressions for computing variables that aren't in the program anymore,
so we have to declare 'this' to be the unadjusted value if we want the
debugger to see the right value.
This has the side benefit that, in optimized builds, the 'this' pointer
will usually be available on function entry because it doesn't require
any adjustment.
Reviewers: hans
Subscribers: aprantl, cfe-commits
Differential Revision: https://reviews.llvm.org/D40109
llvm-svn: 318440
Summary:
Constant samplers are handled as static variables and clang's code generation
library, which leads to llvm::unreachable. We bypass emitting sampler variable
as static since it's translated to a function call later.
Reviewers: yaxunl, Anastasia
Reviewed By: yaxunl, Anastasia
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D34342
llvm-svn: 318290
Summary:
Convert clang::LangAS to a strongly typed enum
Currently both clang AST address spaces and target specific address spaces
are represented as unsigned which can lead to subtle errors if the wrong
type is passed. It is especially confusing in the CodeGen files as it is
not possible to see what kind of address space should be passed to a
function without looking at the implementation.
I originally made this change for our LLVM fork for the CHERI architecture
where we make extensive use of address spaces to differentiate between
capabilities and pointers. When merging the upstream changes I usually
run into some test failures or runtime crashes because the wrong kind of
address space is passed to a function. By converting the LangAS enum to a
C++11 we can catch these errors at compile time. Additionally, it is now
obvious from the function signature which kind of address space it expects.
I found the following errors while writing this patch:
- ItaniumRecordLayoutBuilder::LayoutField was passing a clang AST address
space to TargetInfo::getPointer{Width,Align}()
- TypePrinter::printAttributedAfter() prints the numeric value of the
clang AST address space instead of the target address space.
However, this code is not used so I kept the current behaviour
- initializeForBlockHeader() in CGBlocks.cpp was passing
LangAS::opencl_generic to TargetInfo::getPointer{Width,Align}()
- CodeGenFunction::EmitBlockLiteral() was passing a AST address space to
TargetInfo::getPointerWidth()
- CGOpenMPRuntimeNVPTX::translateParameter() passed a target address space
to Qualifiers::addAddressSpace()
- CGOpenMPRuntimeNVPTX::getParameterAddress() was using
llvm::Type::getPointerTo() with a AST address space
- clang_getAddressSpace() returns either a LangAS or a target address
space. As this is exposed to C I have kept the current behaviour and
added a comment stating that it is probably not correct.
Other than this the patch should not cause any functional changes.
Reviewers: yaxunl, pcc, bader
Reviewed By: yaxunl, bader
Subscribers: jlebar, jholewinski, nhaehnle, Anastasia, cfe-commits
Differential Revision: https://reviews.llvm.org/D38816
llvm-svn: 315871
Currently Clang uses default address space (0) to represent private address space for OpenCL
in AST. There are two issues with this:
Multiple address spaces including private address space cannot be diagnosed.
There is no mangling for default address space. For example, if private int* is emitted as
i32 addrspace(5)* in IR. It is supposed to be mangled as PUAS5i but it is mangled as
Pi instead.
This patch attempts to represent OpenCL private address space explicitly in AST. It adds
a new enum LangAS::opencl_private and adds it to the variable types which are implicitly
private:
automatic variables without address space qualifier
function parameter
pointee type without address space qualifier (OpenCL 1.2 and below)
Differential Revision: https://reviews.llvm.org/D35082
llvm-svn: 315668
the interface.
The ultimate goal here is to make it easier to do some more interesting
things in constant emission, like emit constant initializers that have
ignorable side-effects, or doing the majority of an initialization
in-place and then patching up the last few things with calls. But for
now this is mostly just a refactoring.
llvm-svn: 310964
Certain targets (e.g. amdgcn) require global variable to stay in global or constant address
space. In C or C++ global variables are emitted in the default (generic) address space.
This patch introduces virtual functions TargetCodeGenInfo::getGlobalVarAddressSpace
and TargetInfo::getConstantAddressSpace to handle this in a general approach.
It only affects IR generated for amdgcn target.
Differential Revision: https://reviews.llvm.org/D33842
llvm-svn: 307470
In C++ all variables are in default address space. Previously change has been
made to cast automatic variables to default address space. However that is
not sufficient since all temporary variables need to be casted to default
address space.
This patch casts all temporary variables to default address space except those
for passing indirect arguments since they are only used for load/store.
This patch only affects target having non-zero alloca address space.
Differential Revision: https://reviews.llvm.org/D33706
llvm-svn: 305711
This patch provides a means to specify section-names for global variables,
functions and static variables, using #pragma directives.
This feature is only defined to work sensibly for ELF targets.
One can specify section names as:
#pragma clang section bss="myBSS" data="myData" rodata="myRodata" text="myText"
One can "unspecify" a section name with empty string e.g.
#pragma clang section bss="" data="" text="" rodata=""
Reviewers: Roger Ferrer, Jonathan Roelofs, Reid Kleckner
Differential Revision: https://reviews.llvm.org/D33412
llvm-svn: 304705
Alloca always returns a pointer in alloca address space, which may
be different from the type defined by the language. For example,
in C++ the auto variables are in the default address space. Therefore
cast alloca to the expected address space when necessary.
Differential Revision: https://reviews.llvm.org/D32248
llvm-svn: 303370
CodeGenFunction::EmitObjCForCollectionStmt currently emits lifetime markers for the loop variable in an inconsistent way: lifetime.start is emitted before the loop is entered, but lifetime.end is emitted inside the loop. AddressSanitizer uses these markers to track out-of-scope accesses to local variables, and we get false positives in Obj-C foreach loops (in the 2nd iteration of the loop). This patch keeps the loop variable alive for the whole loop by extending ForScope and registering the cleanup function inside EmitAutoVarAlloca.
Differential Revision: https://reviews.llvm.org/D32029
llvm-svn: 300340
This is a follow-up to r297700 (Add a nullability sanitizer).
It addresses some FIXME's re: using nullability-specific diagnostic
handlers from compiler-rt, now that the necessary handlers exist.
check-ubsan test updates to follow.
llvm-svn: 297750
Teach UBSan to detect when a value with the _Nonnull type annotation
assumes a null value. Call expressions, initializers, assignments, and
return statements are all checked.
Because _Nonnull does not affect IRGen, the new checks are disabled by
default. The new driver flags are:
-fsanitize=nullability-arg (_Nonnull violation in call)
-fsanitize=nullability-assign (_Nonnull violation in assignment)
-fsanitize=nullability-return (_Nonnull violation in return stmt)
-fsanitize=nullability (all of the above)
This patch builds on top of UBSan's existing support for detecting
violations of the nonnull attributes ('nonnull' and 'returns_nonnull'),
and relies on the compiler-rt support for those checks. Eventually we
will need to update the diagnostic messages in compiler-rt (there are
FIXME's for this, which will be addressed in a follow-up).
One point of note is that the nullability-return check is only allowed
to kick in if all arguments to the function satisfy their nullability
preconditions. This makes it necessary to emit some null checks in the
function body itself.
Testing: check-clang and check-ubsan. I also built some Apple ObjC
frameworks with an asserts-enabled compiler, and verified that we get
valid reports.
Differential Revision: https://reviews.llvm.org/D30762
llvm-svn: 297700
in the current lexical scope.
clang currently emits the lifetime.start marker of a variable when the
variable comes into scope even though a variable's lifetime starts at
the entry of the block with which it is associated, according to the C
standard. This normally doesn't cause any problems, but in the rare case
where a goto jumps backwards past the variable declaration to an earlier
point in the block (see the test case added to lifetime2.c), it can
cause mis-compilation.
To prevent such mis-compiles, this commit conservatively disables
emitting lifetime variables when a label has been seen in the current
block.
This problem was discussed on cfe-dev here:
http://lists.llvm.org/pipermail/cfe-dev/2016-July/050066.html
rdar://problem/30153946
Differential Revision: https://reviews.llvm.org/D27680
llvm-svn: 293106
This change introduces UsingPackDecl as a marker for the set of UsingDecls
produced by pack expansion of a single (unresolved) using declaration. This is
not strictly necessary (we just need to be able to map from the original using
declaration to its expansions somehow), but it's useful to maintain the
invariant that each declaration reference instantiates to refer to one
declaration.
This is a re-commit of r290080 (reverted in r290092) with a fix for a
use-after-lifetime bug.
llvm-svn: 290203
This change introduces UsingPackDecl as a marker for the set of UsingDecls
produced by pack expansion of a single (unresolved) using declaration. This is
not strictly necessary (we just need to be able to map from the original using
declaration to its expansions somehow), but it's useful to maintain the
invariant that each declaration reference instantiates to refer to one
declaration.
llvm-svn: 290080
In amdgcn target, null pointers in global, constant, and generic address space take value 0 but null pointers in private and local address space take value -1. Currently LLVM assumes all null pointers take value 0, which results in incorrectly translated IR. To workaround this issue, instead of emit null pointers in local and private address space, a null pointer in generic address space is emitted and casted to local and private address space.
Tentative definition of global variables with non-zero initializer will have weak linkage instead of common linkage since common linkage requires zero initializer and does not have explicit section to hold the non-zero value.
Virtual member functions getNullPointer and performAddrSpaceCast are added to TargetCodeGenInfo which by default returns ConstantPointerNull and emitting addrspacecast instruction. A virtual member function getNullPointerValue is added to TargetInfo which by default returns 0. Each target can override these virtual functions to get target specific null pointer and the null pointer value for specific address space, and perform specific translations for addrspacecast.
Wrapper functions getNullPointer is added to CodegenModule and getTargetNullPointerValue is added to ASTContext to facilitate getting the target specific null pointers and their values.
This change has no effect on other targets except amdgcn target. Other targets can provide support of non-zero null pointer in a similar way.
This change only provides support for non-zero null pointer for C and OpenCL. Supporting for other languages will be added later incrementally.
Differential Revision: https://reviews.llvm.org/D26196
llvm-svn: 289252
Avoid using shortcut for const qualified non-constant address space
aggregate variables while generating them on the stack such that
the alloca object is used instead of a global variable containing
initializer.
Review: https://reviews.llvm.org/D27109
llvm-svn: 288163
Summary: Setting constant address space for global constants used for memcpy-initialization of arrays.
Patch by Alexey Sotkin.
Reviewers: bader, yaxunl, Anastasia
Subscribers: cfe-commits, AlexeySotkin
Differential Revision: https://reviews.llvm.org/D25305
llvm-svn: 285557
abstract information about the callee. NFC.
The goal here is to make it easier to recognize indirect calls and
trigger additional logic in certain cases. That logic will come in
a later patch; in the meantime, I felt that this was a significant
improvement to the code.
llvm-svn: 285258
Summary:
Current generation of lifetime intrinsics does not handle cases like:
```
{
char x;
l1:
bar(&x, 1);
}
goto l1;
```
We will get code like this:
```
%x = alloca i8, align 1
call void @llvm.lifetime.start(i64 1, i8* nonnull %x)
br label %l1
l1:
%call = call i32 @bar(i8* nonnull %x, i32 1)
call void @llvm.lifetime.end(i64 1, i8* nonnull %x)
br label %l1
```
So the second time bar was called for x which is marked as dead.
Lifetime markers here are misleading so it's better to remove them at all.
This type of bypasses are rare, e.g. code detects just 8 functions building
clang (2329 targets).
PR28267
Reviewers: eugenis
Subscribers: beanz, mgorny, cfe-commits
Differential Revision: https://reviews.llvm.org/D24693
llvm-svn: 285176
Summary: D24693 will need access to it from other places
Reviewers: eugenis
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D24695
llvm-svn: 285158
constexpr variable.
When compiling a constexpr NSString initialized with an objective-c
string literal, CodeGen emits objc_storeStrong on an uninitialized
alloca, which causes a crash.
This patch folds the code in EmitScalarInit into EmitStoreThroughLValue
and fixes the crash by calling objc_retain on the string instead of
using objc_storeStrong.
rdar://problem/28562009
Differential Revision: https://reviews.llvm.org/D25547
llvm-svn: 284516
Move the logic for doing this from the ABI argument lowering into
EmitParmDecl, which runs for all parameters. Our codegen is slightly
suboptimal in this case, as we may leave behind a dead store after
optimization, but it's 32-bit inalloca, and this fixes the bug in a
robust way.
Fixes PR30293
llvm-svn: 280836
decomposition declarations.
There are a couple of things in the wording that seem strange here:
decomposition declarations are permitted at namespace scope (which we partially
support here) and they are permitted as the declaration in a template (which we
reject).
llvm-svn: 276492
With all MaterializeTemporaryExprs coming with a ExprWithCleanups, it's
easy to add correct lifetime.end marks into the right RunCleanupsScope.
Differential Revision: http://reviews.llvm.org/D20499
llvm-svn: 274385
Replace inheriting constructors implementation with new approach, voted into
C++ last year as a DR against C++11.
Instead of synthesizing a set of derived class constructors for each inherited
base class constructor, we make the constructors of the base class visible to
constructor lookup in the derived class, using the normal rules for
using-declarations.
For constructors, UsingShadowDecl now has a ConstructorUsingShadowDecl derived
class that tracks the requisite additional information. We create shadow
constructors (not found by name lookup) in the derived class to model the
actual initialization, and have a new expression node,
CXXInheritedCtorInitExpr, to model the initialization of a base class from such
a constructor. (This initialization is special because it performs real perfect
forwarding of arguments.)
In cases where argument forwarding is not possible (for inalloca calls,
variadic calls, and calls with callee parameter cleanup), the shadow inheriting
constructor is not emitted and instead we directly emit the initialization code
into the caller of the inherited constructor.
Note that this new model is not perfectly compatible with the old model in some
corner cases. In particular:
* if B inherits a private constructor from A, and C uses that constructor to
construct a B, then we previously required that A befriends B and B
befriends C, but the new rules require A to befriend C directly, and
* if a derived class has its own constructors (and so its implicit default
constructor is suppressed), it may still inherit a default constructor from
a base class
llvm-svn: 274049
Allow only empty constructors for local __shared__ variables in a way
identical to restrictions imposed on dynamic initializers for global
variables on device.
Differential Revision: http://reviews.llvm.org/D20039
llvm-svn: 268982
Revert the two changes to thread CodeGenOptions into the TargetInfo allocation
and to fix the layering violation by moving CodeGenOptions into Basic.
Code Generation is arguably not particularly "basic". This addresses Richard's
post-commit review comments. This change purely does the mechanical revert and
will be followed up with an alternate approach to thread the desired information
into TargetInfo.
llvm-svn: 265806
This is a mechanical move of CodeGenOptions from libFrontend to libBasic. This
fixes the layering violation introduced earlier by threading CodeGenOptions into
TargetInfo. It should also fix the modules based self-hosting builds. NFC.
llvm-svn: 265702
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
Jake Ehrlich