Commit Graph

3063 Commits

Author SHA1 Message Date
Erich Keane d0f34fd198 Revert "clang support gnu asm goto."
This reverts commit 954ec09aed.

Reverting due to test failures as requested by Jennifer Yu.

Conflicts:
	clang/test/CodeGen/asm-goto.c

llvm-svn: 362106
2019-05-30 15:38:02 +00:00
Jennifer Yu 954ec09aed clang support gnu asm goto.
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
2019-05-30 01:05:46 +00:00
Csaba Dabis dea605e090 [analyzer] print() JSONify: CFG implementation
Summary: -

Reviewers: NoQ, xazax.hun, ravikandhadai, baloghadamsoftware, Szelethus

Reviewed By: NoQ

Subscribers: cfe-commits, szepet, rnkovacs, a.sidorin, mikhail.ramalho,
             donat.nagy, dkrupp

Tags: #clang

Differential Revision: https://reviews.llvm.org/D62496

llvm-svn: 362003
2019-05-29 18:29:31 +00:00
Csaba Dabis 02be650617 [analyzer] print() JSONify: Decl revision
Summary: -

Reviewers: NoQ, xazax.hun, ravikandhadai, baloghadamsoftware, Szelethus

Reviewed By: NoQ

Subscribers: cfe-commits, szepet, rnkovacs, a.sidorin, mikhail.ramalho,
             donat.nagy, dkrupp

Tags: #clang

Differential Revision: https://reviews.llvm.org/D62495

llvm-svn: 362002
2019-05-29 18:21:14 +00:00
Csaba Dabis 9ee26c8d5f [analyzer][AST] print() JSONify: Stmt implementation
Summary:
This patch also adds a function called `JsonFormat()` which:
- Flattens the string so removes the new-lines.
- Escapes double quotes.

Reviewers: NoQ, xazax.hun, ravikandhadai, baloghadamsoftware, Szelethus

Reviewed By: NoQ

Subscribers: cfe-commits, szepet, rnkovacs, a.sidorin, mikhail.ramalho,
             donat.nagy, dkrupp

Tags: #clang

Differential Revision: https://reviews.llvm.org/D62494

llvm-svn: 362000
2019-05-29 18:17:18 +00:00
Csaba Dabis 13e491cca5 [analyzer] print() JSONify: getNodeLabel implementation
Summary: This patch also rewrites the ProgramPoint printing.

Reviewers: NoQ, xazax.hun, ravikandhadai, baloghadamsoftware, Szelethus

Reviewed By: NoQ

Subscribers: cfe-commits, szepet, rnkovacs, a.sidorin, mikhail.ramalho,
             donat.nagy, dkrupp

Tags: #clang

Differential Revision: https://reviews.llvm.org/D62346

llvm-svn: 361997
2019-05-29 18:05:53 +00:00
Csaba Dabis 9ce3746604 [analyzer] print() JSONify: Environment implementation
Summary: -

Reviewers: NoQ, xazax.hun, ravikandhadai, baloghadamsoftware, Szelethus

Reviewed By: NoQ

Subscribers: szepet, rnkovacs, a.sidorin, mikhail.ramalho, donat.nagy,
             dkrupp

Tags: #clang

Differential Revision: https://reviews.llvm.org/D62081

llvm-svn: 361976
2019-05-29 15:36:58 +00:00
Don Hinton 102b4b2486 Revert [test] Fix plugin tests
This reverts r361790 (git commit fe5eaab2b5)

It's causing buildbot breakage, so reverting while I investigate.

llvm-svn: 361793
2019-05-28 06:38:16 +00:00
Don Hinton fe5eaab2b5 [test] Fix plugin tests
Summary:
The following changes were required to fix these tests:

1) Change LLVM_ENABLE_PLUGINS to an option and move it to
   llvm/CMakeLists.txt with an appropriate default -- which matches
   the original default behavior.

2) Move the plugins directory from clang/test/Analysis
   clang/lib/Analysis.  It's not enough to add an exclude to the
   lit.local.cfg file because add_lit_testsuites recurses the tree and
   automatically adds the appropriate `check-` targets, which don't
   make sense for the plugins because they aren't tests and don't
   have `RUN` statements.

   Here's a list of the `clang-check-anlysis*` targets with this
   change:

```
  $ ninja -t targets all| sed -n "s/.*\/\(check[^:]*\):.*/\1/p" | sort -u | grep clang-analysis
  check-clang-analysis
  check-clang-analysis-checkers
  check-clang-analysis-copypaste
  check-clang-analysis-diagnostics
  check-clang-analysis-engine
  check-clang-analysis-exploration_order
  check-clang-analysis-html_diagnostics
  check-clang-analysis-html_diagnostics-relevant_lines
  check-clang-analysis-inlining
  check-clang-analysis-objc
  check-clang-analysis-unified-sources
  check-clang-analysis-z3
```

3) Simplify the logic and only include the subdirectories under
   clang/lib/Analysis/plugins if LLVM_ENABLE_PLUGINS is set.

Reviewed By: NoQ

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D62445

llvm-svn: 361790
2019-05-28 06:26:58 +00:00
Artem Dergachev 192a7474d6 [CFG] Add branch to skip vbase inits when they're handled by superclass.
This patch adds the run-time CFG branch that would skip initialization of
virtual base classes depending on whether the constructor is called from a
superclass constructor or not. Previously the Static Analyzer was already
skipping virtual base-class initializers in such constructors, but it wasn't
skipping their arguments and their potential side effects, which was causing
pr41300 (and was generally incorrect). The previous skipping behavior is
now replaced with a hard assertion that we're not even getting there due
to how our CFG works.

The new CFG element is under a CFG build option so that not to break other
consumers of the CFG by this change. Static Analyzer support for this change
is implemented.

Differential Revision: https://reviews.llvm.org/D61816

llvm-svn: 361681
2019-05-24 23:37:08 +00:00
Artem Dergachev 4e53032d9b [CFG] NFC: Remove implicit conversion from CFGTerminator to Stmt *.
Turn it into a variant class instead. This conversion does indeed save some code
but there's a plan to add support for more kinds of terminators that aren't
necessarily based on statements, and with those in mind it becomes more and more
confusing to have CFGTerminators implicitly convertible to a Stmt *.

Differential Revision: https://reviews.llvm.org/D61814

llvm-svn: 361586
2019-05-24 01:34:22 +00:00
Richard Smith b9fb121a62 [c++20] Implement P1009R2: allow omitting the array bound in an array
new expression.

This was voted into C++20 as a defect report resolution, so we
retroactively apply it to all prior language modes (though it can never
actually be used before C++11 mode).

llvm-svn: 360006
2019-05-06 03:47:15 +00:00
Artem Dergachev ab7747b727 [analyzer] Treat functions without run-time branches as "small".
Currently we always inline functions that have no branches, i.e. have exactly
three CFG blocks: ENTRY, some code, EXIT. This makes sense because when there
are no branches, it means that there's no exponential complexity introduced
by inlining such function. Such functions also don't trigger various fundamental
problems with our inlining mechanism, such as the problem of inlined
defensive checks.

Sometimes the CFG may contain more blocks, but in practice it still has
linear structure because all directions (except, at most, one) of all branches
turned out to be unreachable. When this happens, still treat the function
as "small". This is useful, in particular, for dealing with C++17 if constexpr.

Differential Revision: https://reviews.llvm.org/D61051

llvm-svn: 359531
2019-04-30 03:01:02 +00:00
Artem Dergachev 48e7a2fa8c [analyzer] RetainCount: Add a suppression for "the Matching rule".
In the OSObject universe there appears to be another slightly popular contract,
apart from "create" and "get", which is "matching". It optionally consumes
a "table" parameter and if a table is passed, it fills in the table and
returns it at +0; otherwise, it creates a new table, fills it in and
returns it at +1.

For now suppress false positives by doing a conservative escape on all functions
that end with "Matching", which is the naming convention that seems to be
followed by all such methods.

Differential Revision: https://reviews.llvm.org/D61161

llvm-svn: 359264
2019-04-26 02:05:18 +00:00
Fangrui Song 899d13926d Use llvm::stable_sort
llvm-svn: 359098
2019-04-24 14:43:05 +00:00
Artem Dergachev 727d6ca3f0 [analyzer] Unbreak body farms in presence of multiple declarations.
When growing a body on a body farm, it's essential to use the same redeclaration
of the function that's going to be used during analysis. Otherwise our
ParmVarDecls won't match the ones that are used to identify argument regions.

This boils down to trusting the reasoning in AnalysisDeclContext. We shouldn't
canonicalize the declaration before farming the body because it makes us not
obey the sophisticated decision-making process of AnalysisDeclContext.

Differential Revision: https://reviews.llvm.org/D60899

llvm-svn: 358946
2019-04-23 02:56:00 +00:00
JF Bastien cefafc4999 Thread Safety: also look at ObjC methods
Summary:
SExprBuilder::translateDeclRefExpr was only looking at FunctionDecl and not also looking at ObjCMethodDecl. It should consider both because the attributes can be used on Objective-C as well.

<rdar://problem/48941331>

Reviewers: dexonsmith, erik.pilkington

Subscribers: jkorous, jdoerfert, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D59523

llvm-svn: 356940
2019-03-25 20:06:32 +00:00
Artem Dergachev aa40315c69 [CFG] [analyzer] pr41142: C++17: Skip transparent InitListExprs in constructors.
When searching for construction contexts, i.e. figuring out which statements
define the object that is constructed by each construct-expression, ignore
transparent init-list expressions because they don't add anything to the
context. This allows the Static Analyzer to model construction, destruction,
materialization, lifetime extension correctly in more cases. Also fixes
a crash caused by incorrectly evaluating initial values of variables
initialized with such expressions.

Differential Revision: https://reviews.llvm.org/D59573

llvm-svn: 356634
2019-03-21 00:15:07 +00:00
Aaron Puchert ad4d52a501 Thread safety analysis: Add note for unlock kind mismatch
Summary:
Similar to D56967, we add the existing diag::note_locked_here to tell
the user where we saw the locking that isn't matched correctly.

Reviewers: aaron.ballman, delesley

Reviewed By: aaron.ballman

Subscribers: cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D59455

llvm-svn: 356427
2019-03-18 23:26:54 +00:00
Artem Dergachev f2192b204f [analyzer] RetainCount: A function isn't a CFRetain if it takes no arguments.
Don't crash when a function has a name that starts with "CF" and ends with
"Retain" but takes 0 arguments. In particular, don't try to treat it as if
it returns its first argument.

These problems are inevitable because the checker is naming-convention-based,
but at least we shouldn't crash.

Differential Revision: https://reviews.llvm.org/D59123

llvm-svn: 356223
2019-03-15 00:26:17 +00:00
Petar Jovanovic eb39991c8b [analyzer] handle modification of vars inside an expr with comma operator
We should track mutation of a variable within a comma operator expression.
Current code in ExprMutationAnalyzer does not handle it.

This will handle cases like:

(a, b) ++ < == b is modified
(a, b) = c < == b is modifed


Patch by Djordje Todorovic.

Differential Revision: https://reviews.llvm.org/D58894

llvm-svn: 355605
2019-03-07 15:50:52 +00:00
Fangrui Song 524b3c1810 Fix file headers. NFC
llvm-svn: 355176
2019-03-01 06:49:51 +00:00
Sam McCall 24f135733d Revert "[Analysis] -Wunreachable-code shouldn't fire on the increment of a foreach loop"
This reverts commit r354102.

llvm-svn: 354109
2019-02-15 09:18:49 +00:00
Sam McCall ce2b40def1 [Analysis] -Wunreachable-code shouldn't fire on the increment of a foreach loop
Summary:
The idea is that the code here isn't written, so doesn't indicate a bug.
Similar to code expanded from macros.

This means the warning no longer fires on this code:
  for (auto C : collection) {
    process(C);
    return;
  }
  handleEmptyCollection();
Unclear whether this is more often a bug or not in practice, I think it's a
reasonable idiom in some cases.
Either way, if we want to warn on "loop that doesn't loop", I think it should be
a separate warning, and catch `while(1) break;`

Reviewers: ilya-biryukov, ioeric

Subscribers: cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D58134

llvm-svn: 354102
2019-02-15 07:16:11 +00:00
George Karpenkov 6794aa702a [analyzer] [RetainCountChecker] Bugfix: in non-OSObject-mode, do not track CXX method calls
Differential Revision: https://reviews.llvm.org/D57782

llvm-svn: 353227
2019-02-05 22:26:44 +00:00
Bruno Ricci e64aee87a0 [AST] Update the comments of the various Expr::Ignore* + Related cleanups
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
2019-02-03 19:50:56 +00:00
Erik Pilkington 9c3b588db9 Add a new builtin: __builtin_dynamic_object_size
This builtin has the same UI as __builtin_object_size, but has the
potential to be evaluated dynamically. It is meant to be used as a
drop-in replacement for libraries that use __builtin_object_size when
a dynamic checking mode is enabled. For instance,
__builtin_object_size fails to provide any extra checking in the
following function:

  void f(size_t alloc) {
    char* p = malloc(alloc);
    strcpy(p, "foobar"); // expands to __builtin___strcpy_chk(p, "foobar", __builtin_object_size(p, 0))
  }

This is an overflow if alloc < 7, but because LLVM can't fold the
object size intrinsic statically, it folds __builtin_object_size to
-1. With __builtin_dynamic_object_size, alloc is passed through to
__builtin___strcpy_chk.

rdar://32212419

Differential revision: https://reviews.llvm.org/D56760

llvm-svn: 352665
2019-01-30 20:34:53 +00:00
George Karpenkov 77eae6d4c4 [analyzer] [RetainCountChecker] Bugfix for tracking top-level parameters of Objective-C methods
Differential Revision: https://reviews.llvm.org/D57433

llvm-svn: 352588
2019-01-30 02:11:04 +00:00
Aaron Puchert ffa1d6ad17 Thread safety analysis: Improve diagnostics for double locking
Summary:
We use the existing diag::note_locked_here to tell the user where we saw
the first locking.

Reviewers: aaron.ballman, delesley

Reviewed By: aaron.ballman

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D56967

llvm-svn: 352549
2019-01-29 22:11:42 +00:00
George Karpenkov d37ff4e888 [analyzer] [RetainCountChecker] Track input parameters to the top-level function
Track them for ISL/OS objects by default, and for NS/CF under a flag.

rdar://47536377

Differential Revision: https://reviews.llvm.org/D57356

llvm-svn: 352534
2019-01-29 19:29:59 +00:00
George Karpenkov b0fc58b57c [analyzer] [RetainSummaryManager] [NFC] Split one function into two, as it's really doing two things
Differential Revision: https://reviews.llvm.org/D57201

llvm-svn: 352533
2019-01-29 19:29:45 +00:00
George Karpenkov 2e46667853 [analyzer] [ARCMT] [NFC] Unify entry point into RetainSummaryManager
Just use one single entry point, since we have AnyCall utility now.

Differential Revision: https://reviews.llvm.org/D57346

llvm-svn: 352532
2019-01-29 19:29:33 +00:00
George Karpenkov 0f3bbbaec9 [analyzer] [RetainCountChecker] Support 'taggedRetain' and 'taggedRelease'
Differential Revision: https://reviews.llvm.org/D57211

llvm-svn: 352530
2019-01-29 19:29:07 +00:00
George Karpenkov 6fdd2bd503 [analyzer] Port RetainSummaryManager to the new AnyCall interface, decouple ARCMT from the analyzer
rdar://19694750

Differential Revision: https://reviews.llvm.org/D57127

llvm-svn: 352149
2019-01-25 01:24:04 +00:00
Chandler Carruth 2946cd7010 Update the file headers across all of the LLVM projects in the monorepo
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
2019-01-19 08:50:56 +00:00
Artem Dergachev c2c47f24f5 [analyzer] Do not try to body-farm Objective-C properties with custom accessors.
If a property is defined with a custom getter, we should not behave as if
the getter simply returns an instance variable. We don't support setters,
so they aren't affected.

On top of being the right thing to do, this also fixes a crash on
the newly added test - in which a property and its getter are defined
in two separate categories.

rdar://problem/47051544

Differential Revision: https://reviews.llvm.org/D56823

llvm-svn: 351609
2019-01-18 22:52:13 +00:00
Brian Gesiak 5488ab4ddd [AST] Remove ASTContext from getThisType (NFC)
Summary:
https://reviews.llvm.org/D54862 removed the usages of `ASTContext&` from
within the `CXXMethodDecl::getThisType` method. Remove the parameter
altogether, as well as all usages of it. This does not result in any
functional change because the parameter was unused since
https://reviews.llvm.org/D54862.

Test Plan: check-clang

Reviewers: akyrtzi, mikael

Reviewed By: mikael

Subscribers: mehdi_amini, dexonsmith, cfe-commits

Differential Revision: https://reviews.llvm.org/D56509

llvm-svn: 350914
2019-01-11 01:54:53 +00:00
Bruno Ricci c5885cffc5 [AST] Store the callee and argument expressions of CallExpr in a trailing array.
Since CallExpr::setNumArgs has been removed, it is now possible to store the
callee expression and the argument expressions of CallExpr in a trailing array.
This saves one pointer per CallExpr, CXXOperatorCallExpr, CXXMemberCallExpr,
CUDAKernelCallExpr and UserDefinedLiteral.

Given that CallExpr is used as a base of the above classes we cannot use
llvm::TrailingObjects. Instead we store the offset in bytes from the this pointer
to the start of the trailing objects and manually do the casts + arithmetic.

Some notes:

1.) I did not try to fit the number of arguments in the bit-fields of Stmt.
    This leaves some space for future additions and avoid the discussion about
    whether x bits are sufficient to hold the number of arguments.

2.) It would be perfectly possible to recompute the offset to the trailing
    objects before accessing the trailing objects. However the trailing objects
    are frequently accessed and benchmarks show that it is slightly faster to
    just load the offset from the bit-fields. Additionally, because of 1),
    we have plenty of space in the bit-fields of Stmt.

Differential Revision: https://reviews.llvm.org/D55771

Reviewed By: rjmccall

llvm-svn: 349910
2018-12-21 15:20:32 +00:00
Bruno Ricci 5fc4db7579 [AST][NFC] Pass the AST context to one of the ctor of DeclRefExpr.
All of the other constructors already take a reference to the AST context.
This avoids calling Decl::getASTContext in most cases. Additionally move
the definition of the constructor from Expr.h to Expr.cpp since it is calling
DeclRefExpr::computeDependence. NFC.

llvm-svn: 349901
2018-12-21 14:10:18 +00:00
Artem Dergachev dda42164ec [analyzer] Fix some expressions staying live too long. Add a debug checker.
StaticAnalyzer uses the CFG-based RelaxedLiveVariables analysis in order to,
in particular, figure out values of which expressions are still needed.
When the expression becomes "dead", it is garbage-collected during
the dead binding scan.

Expressions that constitute branches/bodies of control flow statements,
eg. `E1' in `if (C1) E1;' but not `E2' in `if (C2) { E2; }', were kept alive
for too long. This caused false positives in MoveChecker because it relies
on cleaning up loop-local variables when they go out of scope, but some of those
live-for-too-long expressions were keeping a reference to those variables.

Fix liveness analysis to correctly mark these expressions as dead.

Add a debug checker, debug.DumpLiveStmts, in order to test expressions liveness.

Differential Revision: https://reviews.llvm.org/D55566

llvm-svn: 349320
2018-12-16 23:44:06 +00:00
Aaron Puchert 1386b59baf Thread safety analysis: Avoid intermediate copies [NFC]
The main reason is to reduce the number of constructor arguments though,
especially since many of them had the same type.

llvm-svn: 349308
2018-12-16 16:19:11 +00:00
Aaron Puchert 6a68efc959 Thread safety analysis: Allow scoped releasing of capabilities
Summary:
The pattern is problematic with C++ exceptions, and not as widespread as
scoped locks, but it's still used by some, for example Chromium.

We are a bit stricter here at join points, patterns that are allowed for
scoped locks aren't allowed here. That could still be changed in the
future, but I'd argue we should only relax this if people ask for it.

Fixes PR36162.

Reviewers: aaron.ballman, delesley, pwnall

Reviewed By: delesley, pwnall

Subscribers: pwnall, cfe-commits

Differential Revision: https://reviews.llvm.org/D52578

llvm-svn: 349300
2018-12-16 14:15:30 +00:00
Erich Keane 8e46c4b83f Change CallGraph print to show the fully qualified name
CallGraph previously would just show the normal name of a function,
which gets really confusing when using it on large C++ projects.  This
patch switches the printName call to a printQualifiedName, so that the
namespaces are included.

Change-Id: Ie086d863f6b2251be92109ea1b0946825b28b49a
llvm-svn: 348950
2018-12-12 18:11:36 +00:00
Raphael Isemann b23ccecbb0 Misc typos fixes in ./lib folder
Summary: Found via `codespell -q 3 -I ../clang-whitelist.txt -L uint,importd,crasher,gonna,cant,ue,ons,orign,ned`

Reviewers: teemperor

Reviewed By: teemperor

Subscribers: teemperor, jholewinski, jvesely, nhaehnle, whisperity, jfb, cfe-commits

Differential Revision: https://reviews.llvm.org/D55475

llvm-svn: 348755
2018-12-10 12:37:46 +00:00
Fangrui Song 407659ab0a Revert "Revert r347417 "Re-Reinstate 347294 with a fix for the failures.""
It seems the two failing tests can be simply fixed after r348037

Fix 3 cases in Analysis/builtin-functions.cpp
Delete the bad CodeGen/builtin-constant-p.c for now

llvm-svn: 348053
2018-11-30 23:41:18 +00:00
Fangrui Song f5d3335d75 Revert r347417 "Re-Reinstate 347294 with a fix for the failures."
Kept the "indirect_builtin_constant_p" test case in test/SemaCXX/constant-expression-cxx1y.cpp
while we are investigating why the following snippet fails:

  extern char extern_var;
  struct { int a; } a = {__builtin_constant_p(extern_var)};

llvm-svn: 348039
2018-11-30 21:26:09 +00:00
Hans Wennborg 48ee4ad325 Re-commit r347417 "Re-Reinstate 347294 with a fix for the failures."
This was reverted in r347656 due to me thinking it caused a miscompile of
Chromium. Turns out it was the Chromium code that was broken.

llvm-svn: 347756
2018-11-28 14:04:12 +00:00
Hans Wennborg 8c79706e89 Revert r347417 "Re-Reinstate 347294 with a fix for the failures."
This caused a miscompile in Chrome (see crbug.com/908372) that's
illustrated by this small reduction:

  static bool f(int *a, int *b) {
    return !__builtin_constant_p(b - a) || (!(b - a));
  }

  int arr[] = {1,2,3};

  bool g() {
    return f(arr, arr + 3);
  }

  $ clang -O2 -S -emit-llvm a.cc -o -

g() should return true, but after r347417 it became false for some reason.

This also reverts the follow-up commits.

r347417:
> Re-Reinstate 347294 with a fix for the failures.
>
> Don't try to emit a scalar expression for a non-scalar argument to
> __builtin_constant_p().
>
> Third time's a charm!

r347446:
> The result of is.constant() is unsigned.

r347480:
> A __builtin_constant_p() returns 0 with a function type.

r347512:
> isEvaluatable() implies a constant context.
>
> Assume that we're in a constant context if we're asking if the expression can
> be compiled into a constant initializer. This fixes the issue where a
> __builtin_constant_p() in a compound literal was diagnosed as not being
> constant, even though it's always possible to convert the builtin into a
> constant.

r347531:
> A "constexpr" is evaluated in a constant context. Make sure this is reflected
> if a __builtin_constant_p() is a part of a constexpr.

llvm-svn: 347656
2018-11-27 14:01:40 +00:00
Bill Wendling 6ff1751f7d Re-Reinstate 347294 with a fix for the failures.
Don't try to emit a scalar expression for a non-scalar argument to
__builtin_constant_p().

Third time's a charm!

llvm-svn: 347417
2018-11-21 20:44:18 +00:00
Nico Weber 9f0246d473 Revert r347364 again, the fix was incomplete.
llvm-svn: 347389
2018-11-21 12:47:43 +00:00