Commit Graph

4328 Commits

Author SHA1 Message Date
Denys Petrov 01ddfa95bd [analyzer] [NFC] Eliminate dispatchCast, evalCastFromNonLoc and evalCastFromLoc functions from SValBuilder
Summary: Remove dispatchCast, evalCastFromNonLoc and evalCastFromLoc functions since their functionality has been moved to common evalCast function. Use evalCast instead.

Post-clean up patch for https://reviews.llvm.org/D96090 patch. The patch shall not change any behavior.

Differential Revision: https://reviews.llvm.org/D97277
2021-04-13 18:56:04 +03:00
Denys Petrov 7736b08c28 [analyzer] Replace StoreManager::CastRetrievedVal with SValBuilder::evalCast
Summary: Move logic from CastRetrievedVal to evalCast and replace CastRetrievedVal with evalCast. Also move guts from SimpleSValBuilder::dispatchCast inside evalCast.
evalCast intends to substitute dispatchCast, evalCastFromNonLoc and evalCastFromLoc in the future. OriginalTy provides additional information for casting, which is useful for some cases and useless for others.  If `OriginalTy.isNull()` is true, then cast performs based on CastTy only. Now evalCast operates in two ways. It retains all previous behavior and take over dispatchCast behavior. dispatchCast, evalCastFromNonLoc and evalCastFromLoc is considered as buggy since it doesn't take into account OriginalTy of the SVal and should be improved.

From this patch use evalCast instead of dispatchCast, evalCastFromNonLoc and evalCastFromLoc functions. dispatchCast redirects to evalCast.

This patch shall not change any behavior.

Differential Revision: https://reviews.llvm.org/D96090
2021-04-13 18:10:06 +03:00
Saurabh Jha 71ab6c98a0
[Matrix] Implement C-style explicit type conversions for matrix types.
This implements C-style type conversions for matrix types, as specified
in clang/docs/MatrixTypes.rst.

Fixes PR47141.

Reviewed By: fhahn

Differential Revision: https://reviews.llvm.org/D99037
2021-04-10 11:48:41 +01:00
cchen 1a43fd2769 [OpenMP51] Initial support for masked directive and filter clause
Adds basic parsing/sema/serialization support for the #pragma omp masked
directive.

Reviewed By: ABataev

Differential Revision: https://reviews.llvm.org/D99995
2021-04-09 14:00:36 -05:00
Valeriy Savchenko 663ac91ed1 [analyzer] Fix false positives in inner pointer checker (PR49628)
This patch supports std::data and std::addressof functions.

rdar://73463300

Differential Revision: https://reviews.llvm.org/D99260
2021-04-08 20:30:12 +03:00
Valeriy Savchenko 4b958dd6bc [analyzer] Fix crash on spaceship operator (PR47511)
rdar://68954187

Differential Revision: https://reviews.llvm.org/D99181
2021-04-08 20:28:05 +03:00
Valeriy Savchenko 9f0d8bac14 [analyzer] Fix dead store checker false positive
It is common to zero-initialize not only scalar variables,
but also structs.  This is also defensive programming and
we shouldn't complain about that.

rdar://34122265

Differential Revision: https://reviews.llvm.org/D99262
2021-04-08 16:12:42 +03:00
Abhina Sreeskantharajan 82b3e28e83 [SystemZ][z/OS][Windows] Add new OF_TextWithCRLF flag and use this flag instead of OF_Text
Problem:
On SystemZ we need to open text files in text mode. On Windows, files opened in text mode adds a CRLF '\r\n' which may not be desirable.

Solution:
This patch adds two new flags

  - OF_CRLF which indicates that CRLF translation is used.
  - OF_TextWithCRLF = OF_Text | OF_CRLF indicates that the file is text and uses CRLF translation.

Developers should now use either the OF_Text or OF_TextWithCRLF for text files and OF_None for binary files. If the developer doesn't want carriage returns on Windows, they should use OF_Text, if they do want carriage returns on Windows, they should use OF_TextWithCRLF.

So this is the behaviour per platform with my patch:

z/OS:
OF_None: open in binary mode
OF_Text : open in text mode
OF_TextWithCRLF: open in text mode

Windows:
OF_None: open file with no carriage return
OF_Text: open file with no carriage return
OF_TextWithCRLF: open file with carriage return

The Major change is in llvm/lib/Support/Windows/Path.inc to only set text mode if the OF_CRLF is set.
```
  if (Flags & OF_CRLF)
    CrtOpenFlags |= _O_TEXT;
```

These following files are the ones that still use OF_Text which I left unchanged. I modified all these except raw_ostream.cpp in recent patches so I know these were previously in Binary mode on Windows.
./llvm/lib/Support/raw_ostream.cpp
./llvm/lib/TableGen/Main.cpp
./llvm/tools/dsymutil/DwarfLinkerForBinary.cpp
./llvm/unittests/Support/Path.cpp
./clang/lib/StaticAnalyzer/Core/HTMLDiagnostics.cpp
./clang/lib/Frontend/CompilerInstance.cpp
./clang/lib/Driver/Driver.cpp
./clang/lib/Driver/ToolChains/Clang.cpp

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D99426
2021-04-06 07:23:31 -04:00
Balázs Kéri bee4813789 [clang][Checkers] Fix PthreadLockChecker state cleanup at dead symbol.
It is possible that an entry in 'DestroyRetVal' lives longer
than an entry in 'LockMap' if not removed at checkDeadSymbols.
The added test case demonstrates this.

Reviewed By: NoQ

Differential Revision: https://reviews.llvm.org/D98504
2021-04-06 11:15:29 +02:00
Charusso 9b3df78b4c [analyzer] DynamicSize: Rename 'size' to 'extent' 2021-04-05 19:20:43 +02:00
Charusso 89d210fe1a [analyzer] DynamicSize: Debug facility
This patch adds two debug functions to ExprInspectionChecker to dump out
the dynamic extent and element count of symbolic values:
dumpExtent(), dumpElementCount().
2021-04-05 19:17:52 +02:00
Charusso df64f471d1 [analyzer] DynamicSize: Store the dynamic size
This patch introduces a way to store the size.

Reviewed By: NoQ

Differential Revision: https://reviews.llvm.org/D69726
2021-04-05 19:04:53 +02:00
Balázs Kéri df4fa53fdd [clang][Checkers] Extend PthreadLockChecker state dump (NFC).
Add printing of map 'DestroyRetVal'.

Reviewed By: steakhal

Differential Revision: https://reviews.llvm.org/D98502
2021-04-01 11:59:00 +02:00
Balázs Kéri ffcb4b43b7 Revert "[clang][Checkers] Extend PthreadLockChecker state dump (NFC)."
This reverts commit 49c0ab6d76.

Test failures showed up because non-deterministic output.
2021-03-31 15:28:53 +02:00
Balázs Kéri 49c0ab6d76 [clang][Checkers] Extend PthreadLockChecker state dump (NFC).
Add printing of map 'DestroyRetVal'.

Reviewed By: steakhal

Differential Revision: https://reviews.llvm.org/D98502
2021-03-31 11:19:42 +02:00
Mike Rice b7899ba0e8 [OPENMP51]Initial support for the dispatch directive.
Added basic parsing/sema/serialization support for dispatch directive.

Differential Revision: https://reviews.llvm.org/D99537
2021-03-30 14:12:53 -07:00
Valeriy Savchenko 90377308de [analyzer] Support allocClassWithName in OSObjectCStyleCast checker
`allocClassWithName` allocates an object with the given type.
The type is actually provided as a string argument (type's name).
This creates a possibility for not particularly useful warnings
from the analyzer.

In order to combat with those, this patch checks for casts of the
`allocClassWithName` results to types mentioned directly as its
argument.  All other uses of this method should be reasoned about
as before.

rdar://72165694

Differential Revision: https://reviews.llvm.org/D99500
2021-03-30 15:58:06 +03:00
Gabor Marton efa7df1682 [Analyzer] Track RValue expressions
It makes sense to track rvalue expressions in the case of special
concrete integer values. The most notable special value is zero (later
we may find other values). By tracking the origin of 0, we can provide a
better explanation for users e.g. in case of division by 0 warnings.
When the divisor is a product of a multiplication then now we can show
which operand (or both) was (were) zero and why.

Differential Revision: https://reviews.llvm.org/D99344
2021-03-30 14:48:38 +02:00
Gabor Marton 015c39882e [Analyzer] Infer 0 value when the divisible is 0 (bug fix)
Currently, we infer 0 if the divisible of the modulo op is 0:
  int a = x < 0; // a can be 0
  int b = a % y; // b is either 1 % sym or 0
However, we don't when the op is / :
  int a = x < 0; // a can be 0
  int b = a / y; // b is either 1 / sym or 0 / sym

This commit fixes the discrepancy.

Differential Revision: https://reviews.llvm.org/D99343
2021-03-25 18:25:06 +01:00
Gabor Marton f8a850ccf4 [Analyzer][NFC] Fix typos in comments 2021-03-24 11:46:10 +01:00
Valeriy Savchenko 02b51e5316 [analyzer][solver] Redesign constraint ranges data structure
ImmutableSet doesn't seem like the perfect fit for the RangeSet
data structure.  It is good for saving memory in a persistent
setting, but not for the case when the population of the container
is tiny.  This commit replaces RangeSet implementation and
redesigns the most common operations to be more efficient.

Differential Revision: https://reviews.llvm.org/D86465
2021-03-22 13:52:35 +03:00
Valeriy Savchenko 3085bda2b3 [analyzer][solver] Fix infeasible constraints (PR49642)
Additionally, this patch puts an assertion checking for feasible
constraints in every place where constraints are assigned to states.

Differential Revision: https://reviews.llvm.org/D98948
2021-03-22 11:02:02 +03:00
Abhina Sreeskantharajan 4f750f6ebc [SystemZ][z/OS] Distinguish between text and binary files on z/OS
This patch consists of the initial changes to help distinguish between text and binary content correctly on z/OS. I would like to get feedback from Windows users on setting OF_None for all ToolOutputFiles. This seems to have been done as an optimization to prevent CRLF translation on Windows in the past.

Reviewed By: zibi

Differential Revision: https://reviews.llvm.org/D97785
2021-03-19 08:09:57 -04:00
Artem Dergachev c75b2261a0 [analyzer] Introduce common bug category "Unused code".
This category is generic enough to hold a variety of checkers.
Currently it contains the Dead Stores checker and an alpha unreachable
code checker.

Differential Revision: https://reviews.llvm.org/D98741
2021-03-17 20:58:27 -07:00
Mike Rice 410f09af09 [OPENMP51]Initial support for the interop directive.
Added basic parsing/sema/serialization support for interop directive.
Support for the 'init' clause.

Differential Revision: https://reviews.llvm.org/D98558
2021-03-17 09:42:07 -07:00
Vassil Vassilev 0cb7e7ca0c Make iteration over the DeclContext::lookup_result safe.
The idiom:
```
DeclContext::lookup_result R = DeclContext::lookup(Name);
for (auto *D : R) {...}
```

is not safe when in the loop body we trigger deserialization from an AST file.
The deserialization can insert new declarations in the StoredDeclsList whose
underlying type is a vector. When the vector decides to reallocate its storage
the pointer we hold becomes invalid.

This patch replaces a SmallVector with an singly-linked list. The current
approach stores a SmallVector<NamedDecl*, 4> which is around 8 pointers.
The linked list is 3, 5, or 7. We do better in terms of memory usage for small
cases (and worse in terms of locality -- the linked list entries won't be near
each other, but will be near their corresponding declarations, and we were going
to fetch those memory pages anyway). For larger cases: the vector uses a
doubling strategy for reallocation, so will generally be between half-full and
full. Let's say it's 75% full on average, so there's N * 4/3 + 4 pointers' worth
of space allocated currently and will be 2N pointers with the linked list. So we
break even when there are N=6 entries and slightly lose in terms of memory usage
after that. We suspect that's still a win on average.

Thanks to @rsmith!

Differential revision: https://reviews.llvm.org/D91524
2021-03-17 08:59:04 +00:00
Aaron Puchert 1cb15b10ea Correct Doxygen syntax for inline code
There is no syntax like {@code ...} in Doxygen, @code is a block command
that ends with @endcode, and generally these are not enclosed in braces.
The correct syntax for inline code snippets is @c <code>.

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D98665
2021-03-16 15:17:45 +01:00
Valeriy Savchenko 6dc1523508 [analyzer][solver] Prevent infeasible states (PR49490)
This patch fixes the situation when our knowledge of disequalities
can help us figuring out that some assumption is infeasible, but
the solver still produces a state with inconsistent constraints.

Additionally, this patch adds a couple of assertions to catch this
type of problems easier.

Differential Revision: https://reviews.llvm.org/D98341
2021-03-12 15:56:48 +03:00
Adam Balogh bcc662484a [analyzer] Crash fix for alpha.cplusplus.IteratorRange
If the non-iterator side of an iterator operation
`+`, `+=`, `-` or `-=` is `UndefinedVal` an assertions happens.
This small fix prevents this.

Patch by Adam Balogh.

Reviewed By: NoQ

Differential Revision: https://reviews.llvm.org/D85424
2021-03-10 12:42:24 +01:00
Valeriy Savchenko c7635040ce [analyzer] Fix StdLibraryFunctionsChecker performance issue
`initFunctionSummaries` lazily initializes a data structure with
function summaries for standard library functions.  It is called for
every pre-, post-, and eval-call events, i.e. 3 times for each call on
the path.  If the initialization doesn't find any standard library
functions in the translation unit, it will get re-tried (with the same
effect) many times even for small translation units.

For projects not using standard libraries, the speed-up can reach 50%
after this patch.

Differential Revision: https://reviews.llvm.org/D98244
2021-03-10 10:44:04 +03:00
Michael Kruse bc172e532a [clang][StaticAnalyzer] Compilation fix.
An enum was unhandled after landing of D94973. Add the new
OMPCanonicalLoopClass to the list of unhandled cases.
2021-03-04 23:23:58 -06:00
Balazs Benics 38b185832e [analyzer][CTU] API for CTU macro expansions
Removes `CrossTranslationUnitContext::getImportedFromSourceLocation`
Removes the corresponding unit-test segment.

Introduces the `CrossTranslationUnitContext::getMacroExpansionContextForSourceLocation`
which will return the macro expansion context for an imported TU. Also adds a
few implementation FIXME notes where applicable, since this feature is
not implemented yet. This fact is also noted as Doxygen comments.

Uplifts a few CTU LIT test to match the current **incomplete** behavior.

It is a regression to some extent since now we don't expand any
macros in imported TUs. At least we don't crash anymore.

Note that the introduced function is already covered by LIT tests.
Eg.: Analysis/plist-macros-with-expansion-ctu.c

Reviewed By: balazske, Szelethus

Differential Revision: https://reviews.llvm.org/D94673
2021-02-22 11:12:22 +01:00
Balazs Benics 170c67d5b8 [analyzer] Use the MacroExpansionContext for macro expansions in plists
Removes the obsolete ad-hoc macro expansions during bugreport constructions.
It will skip the macro expansion if the expansion happened in an imported TU.

Also removes the expected plist file, while expanding matching context for
the tests.
Adds a previously crashing `plist-macros-with-expansion.c` testfile.
Temporarily marks `plist-macros-with-expansion-ctu.c ` to `XFAIL`.

Reviewed By: xazax.hun, Szelethus

Differential Revision: https://reviews.llvm.org/D93224
2021-02-22 11:12:18 +01:00
Balazs Benics 7c58fb6ba0 [analyzer] Create MacroExpansionContext member in AnalysisConsumer
Adds a `MacroExpansionContext` member to the `AnalysisConsumer` class.
Tracks macro expansions only if the `ShouldDisplayMacroExpansions` is set.
Passes a reference down the pipeline letting AnalysisConsumers query macro
expansions during bugreport construction.

Reviewed By: martong, Szelethus

Differential Revision: https://reviews.llvm.org/D93223
2021-02-22 11:12:14 +01:00
Michael Kruse 6c05005238 [OpenMP] Implement '#pragma omp tile', by Michael Kruse (@Meinersbur).
The tile directive is in OpenMP's Technical Report 8 and foreseeably will be part of the upcoming OpenMP 5.1 standard.

This implementation is based on an AST transformation providing a de-sugared loop nest. This makes it simple to forward the de-sugared transformation to loop associated directives taking the tiled loops. In contrast to other loop associated directives, the OMPTileDirective does not use CapturedStmts. Letting loop associated directives consume loops from different capture context would be difficult.

A significant amount of code generation logic is taking place in the Sema class. Eventually, I would prefer if these would move into the CodeGen component such that we could make use of the OpenMPIRBuilder, together with flang. Only expressions converting between the language's iteration variable and the logical iteration space need to take place in the semantic analyzer: Getting the of iterations (e.g. the overload resolution of `std::distance`) and converting the logical iteration number to the iteration variable (e.g. overload resolution of `iteration + .omp.iv`). In clang, only CXXForRangeStmt is also represented by its de-sugared components. However, OpenMP loop are not defined as syntatic sugar. Starting with an AST-based approach allows us to gradually move generated AST statements into CodeGen, instead all at once.

I would also like to refactor `checkOpenMPLoop` into its functionalities in a follow-up. In this patch it is used twice. Once for checking proper nesting and emitting diagnostics, and additionally for deriving the logical iteration space per-loop (instead of for the loop nest).

Differential Revision: https://reviews.llvm.org/D76342
2021-02-16 09:45:07 -08:00
Kazu Hirata 1a323c8a96 [analyzer] Fix a warning
This patch fixes a warning from -Wcovered-switch-default.  The switch
statement in question handles all the enum values.
2021-02-16 09:12:07 -08:00
Denys Petrov 13f4448ae7 [analyzer] Rework SValBuilder::evalCast function into maintainable and clear way
Summary: Refactor SValBuilder::evalCast function. Make the function clear and get rid of redundant and repetitive code. Unite SValBuilder::evalCast, SimpleSValBuilder::dispatchCast, SimpleSValBuilder::evalCastFromNonLoc and SimpleSValBuilder::evalCastFromLoc functions into single SValBuilder::evalCast.
This patch shall not change any previous behavior.

Differential Revision: https://reviews.llvm.org/D90157
2021-02-16 14:30:51 +02:00
Deep Majumder 21daada950 [analyzer] Fix static_cast on pointer-to-member handling
This commit fixes bug #48739. The bug was caused by the way static_casts
on pointer-to-member caused the CXXBaseSpecifier list of a
MemberToPointer to grow instead of shrink.
The list is now grown by implicit casts and corresponding entries are
removed by static_casts. No-op static_casts cause no effect.

Reviewed By: vsavchenko

Differential Revision: https://reviews.llvm.org/D95877
2021-02-15 11:44:37 +03:00
Daniel Hwang 2407eb08a5 [analyzer] Update static analyzer to be support sarif-html
Updates static analyzer to be able to generate both sarif and html
output in a single run similar to plist-html.

Differential Revision: https://reviews.llvm.org/D96389
2021-02-10 18:34:53 -08:00
Artem Dergachev 3e206a5922 [analyzer] NFC: Introduce reusable bug category for "C++ move semantics".
Currently only used by MoveChecker but ideally all checkers
should have reusable categories.
2021-01-27 03:39:18 -08:00
Simon Pilgrim 879c12d95a Fix null dereference static analysis warning. NFCI.
Replace cast_or_null<> with cast<> as we immediately dereference the pointer afterward so we're not expecting a null pointer.
2021-01-26 16:19:18 +00:00
Alexander Belyaev 9c4b2225b2 Revert "Revert "Revert "Revert "Revert "[analyzer] NFC: Move path diagnostic consumer implementations to libAnalysis."""""
This reverts commit 6b0ee02747.

Circular dependency again.
2021-01-08 14:17:18 +01:00
Artem Dergachev 6b0ee02747 Revert "Revert "Revert "Revert "[analyzer] NFC: Move path diagnostic consumer implementations to libAnalysis.""""
This reverts commit b12f26733a.

Fix dead include that looked like another missed circular dependency.
2021-01-07 20:22:22 -08:00
David Blaikie b12f26733a Revert "Revert "Revert "[analyzer] NFC: Move path diagnostic consumer implementations to libAnalysis."""
This reverts commit d2ddc694ff.

This still contains a circular dependency between Analysis and CrossTU:

$ grep -r include.*Analysis clang/include/clang/CrossTU
clang/include/clang/CrossTU/CrossTranslationUnit.h:
  #include "clang/Analysis/CrossTUAnalysisHelper.h"
$ grep -r include.*CrossTU clang/lib/Analysis
clang/lib/Analysis/PlistHTMLPathDiagnosticConsumer.cpp:
  #include "clang/CrossTU/CrossTranslationUnit.h"
clang/lib/Analysis/PlistPathDiagnosticConsumer.cpp:
  #include "clang/Analysis/CrossTUAnalysisHelper.h"
2021-01-07 18:18:23 -08:00
Artem Dergachev d2ddc694ff Revert "Revert "[analyzer] NFC: Move path diagnostic consumer implementations to libAnalysis.""
This reverts commit 5663bf201f.

The cyclic dependency problem is addressed now.
This is the ~fifth attempt to land this change.
2021-01-07 00:28:22 -08:00
Daniel Hwang 8deaec122e [analyzer] Update Fuchsia checker to catch releasing unowned handles.
Certain Fuchsia functions may return handles that are not owned by the
current closure. This adds a check in order to determine when these
handles are released.

Differential Revision: https://reviews.llvm.org/D93868
2021-01-06 16:23:49 -08:00
Barry Revzin 92310454bf Make LLVM build in C++20 mode
Part of the <=> changes in C++20 make certain patterns of writing equality
operators ambiguous with themselves (sorry!).
This patch goes through and adjusts all the comparison operators such that
they should work in both C++17 and C++20 modes. It also makes two other small
C++20-specific changes (adding a constructor to a type that cases to be an
aggregate, and adding casts from u8 literals which no longer have type
const char*).

There were four categories of errors that this review fixes.
Here are canonical examples of them, ordered from most to least common:

// 1) Missing const
namespace missing_const {
    struct A {
    #ifndef FIXED
        bool operator==(A const&);
    #else
        bool operator==(A const&) const;
    #endif
    };

    bool a = A{} == A{}; // error
}

// 2) Type mismatch on CRTP
namespace crtp_mismatch {
    template <typename Derived>
    struct Base {
    #ifndef FIXED
        bool operator==(Derived const&) const;
    #else
        // in one case changed to taking Base const&
        friend bool operator==(Derived const&, Derived const&);
    #endif
    };

    struct D : Base<D> { };

    bool b = D{} == D{}; // error
}

// 3) iterator/const_iterator with only mixed comparison
namespace iter_const_iter {
    template <bool Const>
    struct iterator {
        using const_iterator = iterator<true>;

        iterator();

        template <bool B, std::enable_if_t<(Const && !B), int> = 0>
        iterator(iterator<B> const&);

    #ifndef FIXED
        bool operator==(const_iterator const&) const;
    #else
        friend bool operator==(iterator const&, iterator const&);
    #endif
    };

    bool c = iterator<false>{} == iterator<false>{} // error
          || iterator<false>{} == iterator<true>{}
          || iterator<true>{} == iterator<false>{}
          || iterator<true>{} == iterator<true>{};
}

// 4) Same-type comparison but only have mixed-type operator
namespace ambiguous_choice {
    enum Color { Red };

    struct C {
        C();
        C(Color);
        operator Color() const;
        bool operator==(Color) const;
        friend bool operator==(C, C);
    };

    bool c = C{} == C{}; // error
    bool d = C{} == Red;
}

Differential revision: https://reviews.llvm.org/D78938
2020-12-17 10:44:10 +00:00
Bardia Mahjour 6eff12788e [DDG] Data Dependence Graph - DOT printer - recommit
This is being recommitted to try and address the MSVC complaint.

This patch implements a DDG printer pass that generates a graph in
the DOT description language, providing a more visually appealing
representation of the DDG. Similar to the CFG DOT printer, this
functionality is provided under an option called -dot-ddg and can
be generated in a less verbose mode under -dot-ddg-only option.

Reviewed By: Meinersbur

Differential Revision: https://reviews.llvm.org/D90159
2020-12-16 12:37:36 -05:00
Bardia Mahjour a29ecca781 Revert "[DDG] Data Dependence Graph - DOT printer"
This reverts commit fd4a10732c, to
investigate the failure on windows: http://lab.llvm.org:8011/#/builders/127/builds/3274
2020-12-14 16:54:20 -05:00
Bardia Mahjour fd4a10732c [DDG] Data Dependence Graph - DOT printer
This patch implements a DDG printer pass that generates a graph in
the DOT description language, providing a more visually appealing
representation of the DDG. Similar to the CFG DOT printer, this
functionality is provided under an option called -dot-ddg and can
be generated in a less verbose mode under -dot-ddg-only option.

Differential Revision: https://reviews.llvm.org/D90159
2020-12-14 16:41:14 -05:00