This is a recommit of b822efc740,
reverted in dc34d8df4c. The commit caused
fails because the test ast-print-fp-pragmas.c did not specify particular
target, and it failed on targets which do not support constrained
intrinsics. The original commit message is below.
AST does not have special nodes for pragmas. Instead a pragma modifies
some state variables of Sema, which in turn results in modified
attributes of AST nodes. This technique applies to floating point
operations as well. Every AST node that can depend on FP options keeps
current set of them.
This technique works well for options like exception behavior or fast
math options. They represent instructions to the compiler how to modify
code generation for the affected nodes. However treatment of FP control
modes has problems with this technique. Modifying FP control mode
(like rounding direction) usually requires operations on hardware, like
writing to control registers. It must be done prior to the first
operation that depends on the control mode. In particular, such
operations are required for implementation of `pragma STDC FENV_ROUND`,
compiler should set up necessary rounding direction at the beginning of
compound statement where the pragma occurs. As there is no representation
for pragmas in AST, the code generation becomes a complicated task in
this case.
To solve this issue FP options are kept inside CompoundStmt. Unlike to FP
options in expressions, these does not affect any operation on FP values,
but only inform the codegen about the FP options that act in the body of
the statement. As all pragmas that modify FP environment may occurs only
at the start of compound statement or at global level, such solution
works for all relevant pragmas. The options are kept as a difference
from the options in the enclosing compound statement or default options,
it helps codegen to set only changed control modes.
Differential Revision: https://reviews.llvm.org/D123952
AST does not have special nodes for pragmas. Instead a pragma modifies
some state variables of Sema, which in turn results in modified
attributes of AST nodes. This technique applies to floating point
operations as well. Every AST node that can depend on FP options keeps
current set of them.
This technique works well for options like exception behavior or fast
math options. They represent instructions to the compiler how to modify
code generation for the affected nodes. However treatment of FP control
modes has problems with this technique. Modifying FP control mode
(like rounding direction) usually requires operations on hardware, like
writing to control registers. It must be done prior to the first
operation that depends on the control mode. In particular, such
operations are required for implementation of `pragma STDC FENV_ROUND`,
compiler should set up necessary rounding direction at the beginning of
compound statement where the pragma occurs. As there is no representation
for pragmas in AST, the code generation becomes a complicated task in
this case.
To solve this issue FP options are kept inside CompoundStmt. Unlike to FP
options in expressions, these does not affect any operation on FP values,
but only inform the codegen about the FP options that act in the body of
the statement. As all pragmas that modify FP environment may occurs only
at the start of compound statement or at global level, such solution
works for all relevant pragmas. The options are kept as a difference
from the options in the enclosing compound statement or default options,
it helps codegen to set only changed control modes.
Differential Revision: https://reviews.llvm.org/D123952
Number of statements in CompoundStmt is kept in a bit-field of the common
part of Stmt. The field has 24 bits for the number. To allocate a new
bit field (as attempted in https://reviews.llvm.org/D123952), this
number must be reduced, maximal number of statements in a compound
statement becomes smaller. It can result in compilation errors of some
programs.
With this change the number of statements is kept in a field of type
'unsigned int' rather than in bit-field. To make room in CompoundStmtBitfields
LBraceLoc is moved to fields of CompoundStmt.
Differential Revision: https://reviews.llvm.org/D125635
I noticed that the following case would compile in Clang but not GCC:
void *x(void) {
void *p = &&foo;
asm goto ("# %0\n\t# %l1":"+r"(p):::foo);
foo:;
return p;
}
Changing the output template above from %l2 would compile in GCC but not
Clang.
This demonstrates that when using tied outputs (say via the "+r" output
constraint), the hidden inputs occur or are numbered BEFORE the labels,
at least with GCC.
In fact, GCC does denote this in its documentation:
https://gcc.gnu.org/onlinedocs/gcc-11.2.0/gcc/Extended-Asm.html#Goto-Labels
> Output operand with constraint modifier ‘+’ is counted as two operands
> because it is considered as one output and one input operand.
For the sake of compatibility, I think it's worthwhile to just make this
change.
It's better to use symbolic names for compatibility (especially now
between released version of Clang that support asm goto with outputs).
ie. %l1 from the above would be %l[foo]. The GCC docs also make this
recommendation.
Also, I cleaned up some cruft in GCCAsmStmt::getNamedOperand. AFAICT,
NumPlusOperands was no longer used, though I couldn't find which commit
didn't clean that up correctly.
Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98096
Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103640
Link: https://gcc.gnu.org/onlinedocs/gcc-11.2.0/gcc/Extended-Asm.html#Goto-Labels
Reviewed By: void
Differential Revision: https://reviews.llvm.org/D115471
Modify the IfStmt node to suppoort constant evaluated expressions.
Add a new ExpressionEvaluationContext::ImmediateFunctionContext to
keep track of immediate function contexts.
This proved easier/better/probably more efficient than walking the AST
backward as it allows diagnosing nested if consteval statements.
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
It doesn't really make sense to emit language specific diagnostics
in a discarded statement, and suppressing these diagnostics results in a
programming pattern that many users will feel is quite useful.
Basically, this makes sure we only emit errors from the 'true' side of a
'constexpr if'.
It does this by making the ExprEvaluatorBase type have an opt-in option
as to whether it should visit discarded cases.
Differential Revision: https://reviews.llvm.org/D102251
Initial support for using the OpenMPIRBuilder by clang to generate loops using the OpenMPIRBuilder. This initial support is intentionally limited to:
* Only the worksharing-loop directive.
* Recognizes only the nowait clause.
* No loop nests with more than one loop.
* Untested with templates, exceptions.
* Semantic checking left to the existing infrastructure.
This patch introduces a new AST node, OMPCanonicalLoop, which becomes parent of any loop that has to adheres to the restrictions as specified by the OpenMP standard. These restrictions allow OMPCanonicalLoop to provide the following additional information that depends on base language semantics:
* The distance function: How many loop iterations there will be before entering the loop nest.
* The loop variable function: Conversion from a logical iteration number to the loop variable.
These allow the OpenMPIRBuilder to act solely using logical iteration numbers without needing to be concerned with iterator semantics between calling the distance function and determining what the value of the loop variable ought to be. Any OpenMP logical should be done by the OpenMPIRBuilder such that it can be reused MLIR OpenMP dialect and thus by flang.
The distance and loop variable function are implemented using lambdas (or more exactly: CapturedStmt because lambda implementation is more interviewed with the parser). It is up to the OpenMPIRBuilder how they are called which depends on what is done with the loop. By default, these are emitted as outlined functions but we might think about emitting them inline as the OpenMPRuntime does.
For compatibility with the current OpenMP implementation, even though not necessary for the OpenMPIRBuilder, OMPCanonicalLoop can still be nested within OMPLoopDirectives' CapturedStmt. Although OMPCanonicalLoop's are not currently generated when the OpenMPIRBuilder is not enabled, these can just be skipped when not using the OpenMPIRBuilder in case we don't want to make the AST dependent on the EnableOMPBuilder setting.
Loop nests with more than one loop require support by the OpenMPIRBuilder (D93268). A simple implementation of non-rectangular loop nests would add another lambda function that returns whether a loop iteration of the rectangular overapproximation is also within its non-rectangular subset.
Reviewed By: jdenny
Differential Revision: https://reviews.llvm.org/D94973
For MASM syntax, the prefixes are not enclosed in braces.
The assembly code should like:
"evex vcvtps2pd xmm0, xmm1"
Differential Revision: https://reviews.llvm.org/D90441
The attribute has no effect on a do statement since the path of execution
will always include its substatement.
It adds a diagnostic when the attribute is used on an infinite while loop
since the codegen omits the branch here. Since the likelihood attributes
have no effect on a do statement no diagnostic will be issued for
do [[unlikely]] {...} while(0);
Differential Revision: https://reviews.llvm.org/D89899
This implements the likelihood attribute for the switch statement. Based on the
discussion in D85091 and D86559 it only handles the attribute when placed on
the case labels or the default labels.
It also marks the likelihood attribute as feature complete. There are more QoI
patches in the pipeline.
Differential Revision: https://reviews.llvm.org/D89210
This is triggered during serialization. The test is for modules, but
will occur for any serialization effort using asm goto.
Reviewed By: nickdesaulniers, jyknight
Differential Revision: https://reviews.llvm.org/D88195
This is the initial part of the implementation of the C++20 likelihood
attributes. It handles the attributes in an if statement.
Differential Revision: https://reviews.llvm.org/D85091
Summary:
Clang's "asm goto" feature didn't initially support outputs constraints. That
was the same behavior as gcc's implementation. The decision by gcc not to
support outputs was based on a restriction in their IR regarding terminators.
LLVM doesn't restrict terminators from returning values (e.g. 'invoke'), so
it made sense to support this feature.
Output values are valid only on the 'fallthrough' path. If an output value's used
on an indirect branch, then it's 'poisoned'.
In theory, outputs *could* be valid on the 'indirect' paths, but it's very
difficult to guarantee that the original semantics would be retained. E.g.
because indirect labels could be used as data, we wouldn't be able to split
critical edges in situations where two 'callbr' instructions have the same
indirect label, because the indirect branch's destination would no longer be
the same.
Reviewers: jyknight, nickdesaulniers, hfinkel
Reviewed By: jyknight, nickdesaulniers
Subscribers: MaskRay, rsmith, hiraditya, llvm-commits, cfe-commits, craig.topper, rnk
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D69876
This is how it should've been and brings it more in line with
std::string_view. There should be no functional change here.
This is mostly mechanical from a custom clang-tidy check, with a lot of
manual fixups. It uncovers a lot of minor inefficiencies.
This doesn't actually modify StringRef yet, I'll do that in a follow-up.
Implement support for C++2a requires-expressions.
Re-commit after compilation failure on some platforms due to alignment issues with PointerIntPair.
Differential Revision: https://reviews.llvm.org/D50360
conservatively assuming they always can.
Also fix cases where we would not consider the computation of a VLA type
when determining whether an expression can throw. We don't yet properly
determine whether a VLA can throw, but no longer incorrectly claim it
can never throw.
Since statements, expressions and types are allocated with the BumpPtrAllocator
from ASTContext their destructor is not executed. Two classes are currently
exempted from the check : InitListExpr due to its ASTVector and
ConstantArrayType due to its APInt.
No functional changes.
Differential Revision: https://reviews.llvm.org/D66646
Reviewed By: lebedev.ri, gribozavr
llvm-svn: 370044
Syntax:
asm [volatile] goto ( AssemblerTemplate
:
: InputOperands
: Clobbers
: GotoLabels)
https://gcc.gnu.org/onlinedocs/gcc/Extended-Asm.html
New llvm IR is "callbr" for inline asm goto instead "call" for inline asm
For:
asm goto("testl %0, %0; jne %l1;" :: "r"(cond)::label_true, loop);
IR:
callbr void asm sideeffect "testl $0, $0; jne ${1:l};", "r,X,X,~{dirflag},~{fpsr},~{flags}"(i32 %0, i8* blockaddress(@foo, %label_true), i8* blockaddress(@foo, %loop)) #1
to label %asm.fallthrough [label %label_true, label %loop], !srcloc !3
asm.fallthrough:
Compiler need to generate:
1> a dummy constarint 'X' for each label.
2> an unique fallthrough label for each asm goto stmt " asm.fallthrough%number".
Diagnostic
1> duplicate asm operand name are used in output, input and label.
2> goto out of scope.
llvm-svn: 362045
Systematically add the const-qualified version of children()
to all statement/expression nodes. Previously the const-qualified
variant was only defined for some nodes. NFC.
Patch by: Nicolas Manichon
Differential Revision: https://reviews.llvm.org/D60029
Reviewed By: riccibruno
llvm-svn: 358288
expression is a discarded-value expression.
Summary:
We used to get this wrong in three ways:
1) During parsing, an expression-statement followed by the }) ending a
statement expression was always treated as producing the value of the
statement expression. That's wrong for ({ if (1) expr; })
2) During template instantiation, various kinds of statement (most
statements not appearing directly in a compound-statement) were not
treated as discarded-value expressions, resulting in missing volatile
loads (etc).
3) In all contexts, an expression-statement with attributes was not
treated as producing the value of the statement expression, eg
({ [[attr]] expr; }).
Also fix incorrect enforcement of OpenMP rule that directives can "only
be placed in the program at a position where ignoring or deleting the
directive would result in a program with correct syntax". In particular,
a label (be it goto, case, or default) should not affect whether
directives are permitted.
Reviewers: aaron.ballman, rjmccall
Subscribers: cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D57984
llvm-svn: 354090
The description of what the various Expr::Ignore* do has drifted from the
actual implementation.
Inspection reveals that IgnoreParenImpCasts() is not equivalent to doing
IgnoreParens() + IgnoreImpCasts() until reaching a fixed point, but
IgnoreParenCasts() is equivalent to doing IgnoreParens() + IgnoreCasts()
until reaching a fixed point. There is also a fair amount of duplication
in the various Expr::Ignore* functions which increase the chance of further
future inconsistencies. In preparation for the next patch which will factor
out the implementation of the various Expr::Ignore*, do the following cleanups:
Remove Stmt::IgnoreImplicit, in favor of Expr::IgnoreImplicit. IgnoreImplicit
is the only function among all of the Expr::Ignore* which is available in Stmt.
There are only a few users of Stmt::IgnoreImplicit. They can just use instead
Expr::IgnoreImplicit like they have to do for the other Ignore*.
Move Expr::IgnoreImpCasts() from Expr.h to Expr.cpp. This made no difference
in the run-time with my usual benchmark (-fsyntax-only on all of Boost).
While we are at it, make IgnoreParenNoopCasts take a const reference to the
ASTContext for const correctness.
Update the comments to match what the Expr::Ignore* are actually doing.
I am not sure that listing exactly what each Expr::Ignore* do is optimal,
but it certainly looks better than the current state which is in my opinion
between misleading and just plain wrong.
The whole patch is NFC (if you count removing Stmt::IgnoreImplicit as NFC).
Differential Revision: https://reviews.llvm.org/D57266
Reviewed By: aaron.ballman
llvm-svn: 353006
to reflect the new license.
We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.
Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.
llvm-svn: 351636
Add a static_assert checking that no statement/expression class
is polymorphic. People should use LLVM style RTTI instead.
Differential Revision: https://reviews.llvm.org/D55222
Reviewed By: aaron.ballman
llvm-svn: 348278
A ConstantExpr class represents a full expression that's in a context where a
constant expression is required. This class reflects the path the evaluator
took to reach the expression rather than the syntactic context in which the
expression occurs.
In the future, the class will be expanded to cache the result of the evaluated
expression so that it's not needlessly re-evaluated
Reviewed By: rsmith
Differential Revision: https://reviews.llvm.org/D53475
llvm-svn: 345692
Only store the NRVO candidate if needed in ReturnStmt.
A good chuck of all of the ReturnStmt have no NRVO candidate
(more than half when parsing all of Boost). For all of them
this saves one pointer. This has no impact on children().
Differential Revision: https://reviews.llvm.org/D53716
Reviewed By: rsmith
llvm-svn: 345605
Don't store the data for the condition variable if not needed.
This cuts the size of WhileStmt by up to a pointer.
The order of the children is kept the same.
Differential Revision: https://reviews.llvm.org/D53715
Reviewed By: rjmccall
llvm-svn: 345597
Don't store the data for the init statement and condition variable
if not needed. This cuts the size of SwitchStmt by up to 2 pointers.
The order of the children is intentionally kept the same.
Also use the newly available space in the bit-fields of Stmt
to store the bit representing whether all enums have been covered
instead of using a PointerIntPair.
Differential Revision: https://reviews.llvm.org/D53714
Reviewed By: rjmccall
llvm-svn: 345510
Don't store the data for case statements of the form LHS ... RHS if not
needed. This cuts the size of CaseStmt by 1 pointer + 1 SourceLocation in
the common case.
Also use the newly available space in the bit-fields of Stmt to store the
keyword location of SwitchCase and move the small accessor
SwitchCase::getSubStmt to the header.
Differential Revision: https://reviews.llvm.org/D53609
Reviewed By: rjmccall
llvm-svn: 345472
Only store the needed data in IfStmt. This cuts the size of IfStmt
by up to 3 pointers + 1 SourceLocation. The order of the children
is intentionally kept the same even though it would be more
convenient to put the optional trailing objects last. Additionally
use the newly available space in the bit-fields of Stmt to store
the location of the "if".
The result of this is that for the common case of an
if statement of the form:
if (some_cond)
some_statement
the size of IfStmt is brought down to 8 bytes + 2 pointers,
instead of 8 bytes + 5 pointers + 2 SourceLocation.
Differential Revision: https://reviews.llvm.org/D53607
Reviewed By: rjmccall
llvm-svn: 345464
Although some classes are using the tail padding of Stmt, most of
them are not. In particular the expression classes are not using it
since there is Expr in between, and Expr contains a single pointer.
This patch widen the bit-fields to Stmt to 8 bytes and move some
data from NullStmt, CompoundStmt, LabelStmt, AttributedStmt, SwitchStmt,
WhileStmt, DoStmt, ForStmt, GotoStmt, ContinueStmt, BreakStmt
and ReturnStmt to the newly available space.
In itself this patch do not achieve much but I plan to go through each of
the classes in the statement/expression hierarchy and use this newly
available space. A quick estimation gives me that this should shrink the
size of the statement/expression hierarchy by >10% when parsing all of Boost.
Differential Revision: https://reviews.llvm.org/D53604
Reviewed By: rjmccall
llvm-svn: 345459
The generated identifiers are stable across multiple runs, and can be a
great debug or visualization aid.
Differential Revision: https://reviews.llvm.org/D51822
llvm-svn: 342309
Summary:
A CXXBindTemporaryExpr can appear inside an ImplicitCastExpr, and was
not ignored previously.
Fixes the case reported in PR37327.
Reviewers: rsmith, dblaikie, klimek
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D50666
llvm-svn: 339730
This is similar to the LLVM change https://reviews.llvm.org/D46290.
We've been running doxygen with the autobrief option for a couple of
years now. This makes the \brief markers into our comments
redundant. Since they are a visual distraction and we don't want to
encourage more \brief markers in new code either, this patch removes
them all.
Patch produced by
for i in $(git grep -l '\@brief'); do perl -pi -e 's/\@brief //g' $i & done
for i in $(git grep -l '\\brief'); do perl -pi -e 's/\\brief //g' $i & done
Differential Revision: https://reviews.llvm.org/D46320
llvm-svn: 331834
Found via codespell -q 3 -I ../clang-whitelist.txt
Where whitelist consists of:
archtype
cas
classs
checkk
compres
definit
frome
iff
inteval
ith
lod
methode
nd
optin
ot
pres
statics
te
thru
Patch by luzpaz! (This is a subset of D44188 that applies cleanly with a few
files that have dubious fixes reverted.)
Differential revision: https://reviews.llvm.org/D44188
llvm-svn: 329399
Serge Pavlov