On AIX when there is a pragma pack, or pragma align in effect then zero-width bitfields should pad out to the end of the bitfield container but not increase the alignment requirements of the struct greater then the max field align.
Reviewed By: ZarkoCA
Differential Revision: https://reviews.llvm.org/D105635
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
This change is intended as initial setup. The plan is to add
more semantic checks later. I plan to update the documentation
as more semantic checks are added (instead of documenting the
details up front). Most of the code closely mirrors that for
the Swift calling convention. Three places are marked as
[FIXME: swiftasynccc]; those will be addressed once the
corresponding convention is introduced in LLVM.
Reviewed By: rjmccall
Differential Revision: https://reviews.llvm.org/D95561
C++23 will make these conversions ambiguous - so fix them to make the
codebase forward-compatible with C++23 (& a follow-up change I've made
will make this ambiguous/invalid even in <C++23 so we don't regress
this & it generally improves the code anyway)
When building the member call to a user conversion function during an
implicit cast, the expression was not being checked for immediate
invocation, so we were never adding the ConstantExpr node to AST.
This would cause the call to the user conversion operator to be emitted
even if it was constantexpr evaluated, and this would even trip an
assert when said user conversion was declared consteval:
`Assertion failed: !cast<FunctionDecl>(GD.getDecl())->isConsteval() && "consteval function should never be emitted", file clang\lib\CodeGen\CodeGenModule.cpp, line 3530`
Fixes PR48855.
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
Reviewed By: rsmith
Differential Revision: https://reviews.llvm.org/D105446
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
This fixes a gap in the `overloadable` attribute support (K&R declared
functions would get mangled symbol names, but that name wouldn't be
represented in the debug info linkage name field for the function) and
in -funique-internal-linkage-names (this came up in review discussion on
D98799) where K&R static declarations would not get the uniqued linkage
names.
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
This option implies -fdump-record-layouts but dumps record layout information with canonical field types, which can be more useful in certain cases when comparing structure layouts.
Reviewed By: stevewan
Differential Revision: https://reviews.llvm.org/D105112
Before this patch, the dependence of CallExpr was only computed in the
constructor, the dependence bits might not reflect truth -- some arguments might
be not set (nullptr) during this time, e.g. CXXDefaultArgExpr will be set via
the setArg method in the later parsing stage, so we need to recompute the
dependence bits.
This patch adds a new clang builtin, __arithmetic_fence. The purpose of the
builtin is to provide the user fine control, at the expression level, over
floating point optimization when -ffast-math (-ffp-model=fast) is enabled.
The builtin prevents the optimizer from rearranging floating point expression
evaluation. The new option fprotect-parens has the same effect on
parenthesized expressions, forcing the optimizer to respect the parentheses.
Reviewed By: aaron.ballman, kpn
Differential Revision: https://reviews.llvm.org/D100118
If a default template type argument is manually specified to be of the default
type, then it is committed when printing the template.
Differential revision: https://reviews.llvm.org/D103040
This patch adds a new clang builtin, __arithmetic_fence. The purpose of the
builtin is to provide the user fine control, at the expression level, over
floating point optimization when -ffast-math (-ffp-model=fast) is enabled.
The builtin prevents the optimizer from rearranging floating point expression
evaluation. The new option fprotect-parens has the same effect on
parenthesized expressions, forcing the optimizer to respect the parentheses.
Reviewed By: aaron.ballman, kpn
Differential Revision: https://reviews.llvm.org/D100118
This ensures that the mangled type names match between C and C++,
which is significant when using -fsanitize=cfi-icall. Ideally we
wouldn't have created this namespace at all, but it's now part of
the ABI (e.g. in mangled names), so we can't change it.
Differential Revision: https://reviews.llvm.org/D104830
Non-throwing allocators currently will always get null-check code. However, if the non-throwing allocator is explicitly annotated with returns_nonnull the null check should be elided.
Testing:
ninja check-all
added test case correctly elides
Reviewed By: bruno
Differential Revision: https://reviews.llvm.org/D102820
According to https://eel.is/c++draft/over.literal
> double operator""_Bq(long double); // OK: does not use the reserved identifier _Bq ([lex.name])
> double operator"" _Bq(long double); // ill-formed, no diagnostic required: uses the reserved identifier _Bq ([lex.name])
Obey that rule by keeping track of the operator literal name status wrt. leading whitespace.
Fix: https://bugs.llvm.org/show_bug.cgi?id=50644
Differential Revision: https://reviews.llvm.org/D104299
This change adds an option which, in addition to dumping the record
layout as is done by -fdump-record-layouts, causes us to compute the
layout for all complete record types (rather than the as-needed basis
which is usually done by clang), so that we will dump them as well.
This is useful if we are looking for layout differences across large
code bases without needing to instantiate every type we are interested in.
Reviewed By: dexonsmith
Differential Revision: https://reviews.llvm.org/D104484
Template parameters are created in ASTImporter with the translation unit as DeclContext.
The DeclContext is later updated (by the create function of template classes).
ASTImporterLookupTable was not updated after these changes of the DC. The patch
adds update of the DeclContext in ASTImporterLookupTable.
Reviewed By: martong
Differential Revision: https://reviews.llvm.org/D103792
This patch addresses a performance issue I noticed when using clang-12 to compile projects of mine. Even though the files weren't too large (around 1k cpp), the compiler was taking more than a minute to compile the source file, much longer than either GCC or MSVC.
Using a profiler it turned out the issue was the isAnyDestructorNoReturn function in CXXRecordDecl. In particular it being recursive, recalculating the property for every invocation, for every field and base class. This showed up in tracebacks in the profiler.
This patch instead adds IsAnyDestructorNoReturn as a Field to the data inside of CXXRecord and updates when a new base class, destructor, or record field member is added.
After this patch the problematic file of mine went from a compile time of 81s, down to 12s.
The patch itself should not change any functionality, just improve performance.
Differential Revision: https://reviews.llvm.org/D104182
<string> is currently the highest impact header in a clang+llvm build:
https://commondatastorage.googleapis.com/chromium-browser-clang/llvm-include-analysis.html
One of the most common places this is being included is the APInt.h header, which needs it for an old toString() implementation that returns std::string - an inefficient method compared to the SmallString versions that it actually wraps.
This patch replaces these APInt/APSInt methods with a pair of llvm::toString() helpers inside StringExtras.h, adjusts users accordingly and removes the <string> from APInt.h - I was hoping that more of these users could be converted to use the SmallString methods, but it appears that most end up creating a std::string anyhow. I avoided trying to use the raw_ostream << operators as well as I didn't want to lose having the integer radix explicit in the code.
Differential Revision: https://reviews.llvm.org/D103888
Implementation of the unroll directive introduced in OpenMP 5.1. Follows the approach from D76342 for the tile directive (i.e. AST-based, not using the OpenMPIRBuilder). Tries to use `llvm.loop.unroll.*` metadata where possible, but has to fall back to an AST representation of the outer loop if the partially unrolled generated loop is associated with another directive (because it needs to compute the number of iterations).
Reviewed By: ABataev
Differential Revision: https://reviews.llvm.org/D99459
Before this change, CXXDefaultArgExpr would always have
ExprDependence::None. This can lead to issues when, for example, the
inner expression is RecoveryExpr and yet containsErrors() on the default
expression is false.
Differential Revision: https://reviews.llvm.org/D103982
This renames the expression value categories from rvalue to prvalue,
keeping nomenclature consistent with C++11 onwards.
C++ has the most complicated taxonomy here, and every other language
only uses a subset of it, so it's less confusing to use the C++ names
consistently, and mentally remap to the C names when working on that
context (prvalue -> rvalue, no xvalues, etc).
Renames:
* VK_RValue -> VK_PRValue
* Expr::isRValue -> Expr::isPRValue
* SK_QualificationConversionRValue -> SK_QualificationConversionPRValue
* JSON AST Dumper Expression nodes value category: "rvalue" -> "prvalue"
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
Reviewed By: rsmith
Differential Revision: https://reviews.llvm.org/D103720
This implements the 'using enum maybe-qualified-enum-tag ;' part of
1099. It introduces a new 'UsingEnumDecl', subclassed from
'BaseUsingDecl'. Much of the diff is the boilerplate needed to get the
new class set up.
There is one case where we accept ill-formed, but I believe this is
merely an extended case of an existing bug, so consider it
orthogonal. AFAICT in class-scope the c++20 rule is that no 2 using
decls can bring in the same target decl ([namespace.udecl]/8). But we
already accept:
struct A { enum { a }; };
struct B : A { using A::a; };
struct C : B { using A::a;
using B::a; }; // same enumerator
this patch permits mixtures of 'using enum Bob;' and 'using Bob::member;' in the same way.
Differential Revision: https://reviews.llvm.org/D102241
This is a pre-patch for adding using-enum support. It breaks out
the shadow decl handling of UsingDecl to a new intermediate base
class, BaseUsingDecl, altering the decl hierarchy to
def BaseUsing : DeclNode<Named, "", 1>;
def Using : DeclNode<BaseUsing>;
def UsingPack : DeclNode<Named>;
def UsingShadow : DeclNode<Named>;
def ConstructorUsingShadow : DeclNode<UsingShadow>;
Differential Revision: https://reviews.llvm.org/D101777
ParmVarDecl is created with translation unit as the parent DeclContext
and later moved to the correct DeclContext. ASTImporterLookupTable
should be updated at this move.
Reviewed By: martong
Differential Revision: https://reviews.llvm.org/D103231
Template args of outer types were not fully-qualified when calling getFullyQualifiedType() for inner types.
For simplicity the patch is a copy-paste of the same call from getFullyQualifiedType().
Reviewed at: https://reviews.llvm.org/D103039
The PreInits of a loop transformation (atm moment only tile) include the computation of the trip count. The trip count is needed by any loop-associated directives that consumes the transformation-generated loop. Hence, we must ensure that the PreInits of consumed loop transformations are emitted with the consuming directive.
This is done by addinging the inner loop transformation's PreInits to the outer loop-directive's PreInits. The outer loop-directive will consume the de-sugared AST such that the inner PreInits are not emitted twice. The PreInits of a loop transformation are still emitted directly if its generated loop(s) are not associated with another loop-associated directive.
Reviewed By: ABataev
Differential Revision: https://reviews.llvm.org/D102180
In the case where the device is an itanium target, and the host is a
windows target, we were getting the names wrong, since in the itanium
case we filter by lambda-signature.
The fix is to always filter by the signature rather than just on
non-windows builds. I considered doing the reverse (that is, checking
the aux-triple), but doing so would result in duplicate lambda mangling
numbers (from linux reusing the same number for different signatures).
This attribute applies to a using declaration, and permits importing a
declaration without knowing if that declaration exists. This is useful
for libc++ C wrapper headers that re-export declarations in std::, in
cases where the base C library doesn't provide all declarations.
This attribute was proposed in http://lists.llvm.org/pipermail/cfe-dev/2020-June/066038.html.
rdar://69313357
Differential Revision: https://reviews.llvm.org/D90188
I discovered when merging the __builtin_sycl_unique_stable_name into my
downstream that it is actually possible for the cc1 invocation to have
more than 1 Sema instance, if you pass it multiple input files, each
gets its own Sema instance and thus ASTContext instance. The result was
that the call to Filter the SYCL kernels was using an
ItaniumMangleContext stored via a 'magic static', so it had an invalid
reference to ASTContext when processing the 2nd failure.
The failure is unfortunately flakey/transient, but the test that fails
was added anyway.
The magic-static was switched to a unique_ptr member variable in
ASTContext that is initialized when needed.
The original version of this was reverted, and @rjmcall provided some
advice to architect a new solution. This is that solution.
This implements a builtin to provide a unique name that is stable across
compilations of this TU for the purposes of implementing the library
component of the unnamed kernel feature of SYCL. It does this by
running the Itanium mangler with a few modifications.
Because it is somewhat common to wrap non-kernel-related lambdas in
macros that aren't present on the device (such as for logging), this
uniquely generates an ID for all lambdas involved in the naming of a
kernel. It uses the lambda-mangling number to do this, except replaces
this with its own number (starting at 10000 for readabililty reasons)
for lambdas used to name a kernel.
Additionally, this implements itself as constexpr with a slight catch:
if a name would be invalidated by the use of this lambda in a later
kernel invocation, it is diagnosed as an error (see the Sema tests).
Differential Revision: https://reviews.llvm.org/D103112
GCC allows each target to define a set of non-letter and non-digit
escaped characters for inline assembly that will be replaced by another
string (They call this "punctuation" characters. The existing "%%" and
"%{" -- replaced by '%' and '{' at the end -- can be seen as special
cases shared by all targets).
This patch implements this feature by adding a new hook in `TargetInfo`.
Differential Revision: https://reviews.llvm.org/D103036
We were always storing a regular ValueDecl* as decomposition declaration
and haven't been using the opportunity to initialize it lazily.
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D99455
In the case of TypedefDecls we set the DeclContext after we imported it.
It turns out, it could lead to null pointer dereferences during the
cleanup part of a failed import.
This patch demonstrates this issue and fixes it by checking if the
DeclContext is available or not.
Reviewed By: shafik
Differential Revision: https://reviews.llvm.org/D102640
This patch is the Part-1 (FE Clang) implementation of HW Exception handling.
This new feature adds the support of Hardware Exception for Microsoft Windows
SEH (Structured Exception Handling).
This is the first step of this project; only X86_64 target is enabled in this patch.
Compiler options:
For clang-cl.exe, the option is -EHa, the same as MSVC.
For clang.exe, the extra option is -fasync-exceptions,
plus -triple x86_64-windows -fexceptions and -fcxx-exceptions as usual.
NOTE:: Without the -EHa or -fasync-exceptions, this patch is a NO-DIFF change.
The rules for C code:
For C-code, one way (MSVC approach) to achieve SEH -EHa semantic is to follow
three rules:
* First, no exception can move in or out of _try region., i.e., no "potential
faulty instruction can be moved across _try boundary.
* Second, the order of exceptions for instructions 'directly' under a _try
must be preserved (not applied to those in callees).
* Finally, global states (local/global/heap variables) that can be read
outside of _try region must be updated in memory (not just in register)
before the subsequent exception occurs.
The impact to C++ code:
Although SEH is a feature for C code, -EHa does have a profound effect on C++
side. When a C++ function (in the same compilation unit with option -EHa ) is
called by a SEH C function, a hardware exception occurs in C++ code can also
be handled properly by an upstream SEH _try-handler or a C++ catch(...).
As such, when that happens in the middle of an object's life scope, the dtor
must be invoked the same way as C++ Synchronous Exception during unwinding
process.
Design:
A natural way to achieve the rules above in LLVM today is to allow an EH edge
added on memory/computation instruction (previous iload/istore idea) so that
exception path is modeled in Flow graph preciously. However, tracking every
single memory instruction and potential faulty instruction can create many
Invokes, complicate flow graph and possibly result in negative performance
impact for downstream optimization and code generation. Making all
optimizations be aware of the new semantic is also substantial.
This design does not intend to model exception path at instruction level.
Instead, the proposed design tracks and reports EH state at BLOCK-level to
reduce the complexity of flow graph and minimize the performance-impact on CPP
code under -EHa option.
One key element of this design is the ability to compute State number at
block-level. Our algorithm is based on the following rationales:
A _try scope is always a SEME (Single Entry Multiple Exits) region as jumping
into a _try is not allowed. The single entry must start with a seh_try_begin()
invoke with a correct State number that is the initial state of the SEME.
Through control-flow, state number is propagated into all blocks. Side exits
marked by seh_try_end() will unwind to parent state based on existing
SEHUnwindMap[].
Note side exits can ONLY jump into parent scopes (lower state number).
Thus, when a block succeeds various states from its predecessors, the lowest
State triumphs others. If some exits flow to unreachable, propagation on those
paths terminate, not affecting remaining blocks.
For CPP code, object lifetime region is usually a SEME as SEH _try.
However there is one rare exception: jumping into a lifetime that has Dtor but
has no Ctor is warned, but allowed:
Warning: jump bypasses variable with a non-trivial destructor
In that case, the region is actually a MEME (multiple entry multiple exits).
Our solution is to inject a eha_scope_begin() invoke in the side entry block to
ensure a correct State.
Implementation:
Part-1: Clang implementation described below.
Two intrinsic are created to track CPP object scopes; eha_scope_begin() and eha_scope_end().
_scope_begin() is immediately added after ctor() is called and EHStack is pushed.
So it must be an invoke, not a call. With that it's also guaranteed an
EH-cleanup-pad is created regardless whether there exists a call in this scope.
_scope_end is added before dtor(). These two intrinsics make the computation of
Block-State possible in downstream code gen pass, even in the presence of
ctor/dtor inlining.
Two intrinsic, seh_try_begin() and seh_try_end(), are added for C-code to mark
_try boundary and to prevent from exceptions being moved across _try boundary.
All memory instructions inside a _try are considered as 'volatile' to assure
2nd and 3rd rules for C-code above. This is a little sub-optimized. But it's
acceptable as the amount of code directly under _try is very small.
Part-2 (will be in Part-2 patch): LLVM implementation described below.
For both C++ & C-code, the state of each block is computed at the same place in
BE (WinEHPreparing pass) where all other EH tables/maps are calculated.
In addition to _scope_begin & _scope_end, the computation of block state also
rely on the existing State tracking code (UnwindMap and InvokeStateMap).
For both C++ & C-code, the state of each block with potential trap instruction
is marked and reported in DAG Instruction Selection pass, the same place where
the state for -EHsc (synchronous exceptions) is done.
If the first instruction in a reported block scope can trap, a Nop is injected
before this instruction. This nop is needed to accommodate LLVM Windows EH
implementation, in which the address in IPToState table is offset by +1.
(note the purpose of that is to ensure the return address of a call is in the
same scope as the call address.
The handler for catch(...) for -EHa must handle HW exception. So it is
'adjective' flag is reset (it cannot be IsStdDotDot (0x40) that only catches
C++ exceptions).
Suppress push/popTerminate() scope (from noexcept/noTHrow) so that HW
exceptions can be passed through.
Original llvm-dev [RFC] discussions can be found in these two threads below:
https://lists.llvm.org/pipermail/llvm-dev/2020-March/140541.htmlhttps://lists.llvm.org/pipermail/llvm-dev/2020-April/141338.html
Differential Revision: https://reviews.llvm.org/D80344/new/
1.[bool, char, short] bitfields have the same alignment as unsigned int
2.Adjust alignment on typedef field decls/honor align attribute
3.Fix alignment for scoped enum class
4.Long long bitfield has 4bytes alignment and StorageUnitSize under 32 bit
compile mode
Differential Revision: https://reviews.llvm.org/D87029
Steven Wan