Commit Graph

24799 Commits

Author SHA1 Message Date
Aaron Puchert df195d8aed Suggestions to fix -Wmissing-{prototypes,variable-declarations}
Summary:
I've found that most often the proper way to fix this warning is to add
`static`, because if the code otherwise compiles and links, the function
or variable is apparently not needed outside of the TU.

We can't provide a fix-it hint for variable declarations, because
multiple VarDecls can share the same type, and if we put static in front
of that, we affect all declared variables, some of which might have
previous declarations.

We also provide no fix-it hint for the rare case of an `extern` function
definition, because that would require removing `extern` and I have no
idea how to get the source location of the storage class specifier from
a FunctionDecl. I believe this information is only available earlier in
the AST construction from DeclSpec::getStorageClassSpecLoc(), but we
don't have that here.

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D59402

llvm-svn: 363749
2019-06-18 22:57:08 +00:00
Aaron Puchert f9c6e565de Show note for -Wmissing-prototypes for functions with parameters
Summary:
There was a search for non-prototype declarations for the function, but
we only showed the results for zero-parameter functions. Now we show the
note for functions with parameters as well, but we omit the fix-it hint
suggesting to add `void`.

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D62750

llvm-svn: 363748
2019-06-18 22:52:39 +00:00
Ilya Biryukov 5aed309a4f [Syntax] Add a helper to find expansion by its first spelled token
Summary: Used in clangd for a code tweak that expands a macro.

Reviewers: sammccall

Reviewed By: sammccall

Subscribers: kadircet, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D62954

llvm-svn: 363698
2019-06-18 16:27:27 +00:00
Matt Arsenault 2acc717627 AMDGPU: Add GWS instruction builtins
llvm-svn: 363684
2019-06-18 14:10:01 +00:00
Fangrui Song 2d94dd812f Revert D60974 "[clang-ifs] Clang Interface Stubs, first version."
This reverts commit rC363626.

clangIndex depends on clangFrontend. r363626 adds a dependency from
clangFrontend to clangIndex, which creates a circular dependency.

This is disallowed by -DBUILD_SHARED_LIBS=on builds:

    CMake Error: The inter-target dependency graph contains the following strongly connected component (cycle):
      "clangFrontend" of type SHARED_LIBRARY
        depends on "clangIndex" (weak)
      "clangIndex" of type SHARED_LIBRARY
        depends on "clangFrontend" (weak)
    At least one of these targets is not a STATIC_LIBRARY.  Cyclic dependencies are allowed only among static libraries.

Note, the dependency on clangIndex cannot be removed because
libclangFrontend.so is linked with -Wl,-z,defs: a shared object must
have its full direct dependencies specified on the linker command line.

In -DBUILD_SHARED_LIBS=off builds, this appears to work when linking
`bin/clang-9`. However, it can cause trouble to downstream clang library
users. The llvm build system links libraries this way:

    clang main_program_object_file ... lib/libclangIndex.a ...  lib/libclangFrontend.a -o exe

libclangIndex.a etc are not wrapped in --start-group.

If the downstream application depends on libclangFrontend.a but not any
other clang libraries that depend on libclangIndex.a, this can cause undefined
reference errors when the linker is ld.bfd or gold.

The proper fix is to not include clangIndex files in clangFrontend.

llvm-svn: 363649
2019-06-18 05:52:39 +00:00
Puyan Lotfi 8df7f1a218 [clang-ifs] Clang Interface Stubs, first version.
Clang interface stubs (previously referred to as clang-ifsos) is a new frontend
action in clang that allows the generation of stub files that contain mangled
name info that can be used to produce a stub library. These stub libraries can
be useful for breaking up build dependencies and controlling access to a
library's internal symbols. Generation of these stubs can be invoked by:

clang -fvisibility=<visibility> -emit-interface-stubs \
                                -interface-stub-version=<interface format>

Notice that -fvisibility (along with use of visibility attributes) can be used
to control what symbols get generated. Currently the interface format is
experimental but there are a wide range of possibilities here.

Differential Revision: https://reviews.llvm.org/D60974

llvm-svn: 363626
2019-06-17 22:46:54 +00:00
Michael Liao b8e8b1769f [clang][AST] Remove unnecessary 'const'.
llvm-svn: 363585
2019-06-17 17:47:03 +00:00
Francis Visoiu Mistrih 34667519dc [Remarks] Extend -fsave-optimization-record to specify the format
Use -fsave-optimization-record=<format> to specify a different format
than the default, which is YAML.

For now, only YAML is supported.

llvm-svn: 363573
2019-06-17 16:06:00 +00:00
Nico Weber 37b7533682 Promote -fdebug-compilation-dir from a cc1 flag to clang and clang-cl driver flags
The flag is useful when wanting to create .o files that are independent
from the absolute path to the build directory. -fdebug-prefix-map= can
be used to the same effect, but it requires putting the absolute path
to the build directory on the build command line, so it still requires
the build command line to be dependent on the absolute path of the build
directory. With this flag, "-fdebug-compilation-dir ." makes it so that
both debug info and the compile command itself are independent of the
absolute path of the build directory, which is good for build
determinism (in the sense that the build is independent of which
directory it happens in) and for caching compile results.
(The tradeoff is that the debugger needs explicit configuration to know
the build directory. See also http://dwarfstd.org/ShowIssue.php?issue=171130.2)

Differential Revision: https://reviews.llvm.org/D63387

llvm-svn: 363548
2019-06-17 12:10:40 +00:00
Sven van Haastregt 9d81915fca Recommit [OpenCL] Move OpenCLBuiltins.td and remove unused include
Reland r363242 after fixing an issue with the tablegen dependence.

Patch by Pierre Gondois and Sven van Haastregt.

Differential revision: https://reviews.llvm.org/D62849

llvm-svn: 363541
2019-06-17 10:06:34 +00:00
Aaron Puchert e1dc495e63 [Clang] Harmonize Split DWARF options with llc
Summary:
With Split DWARF the resulting object file (then called skeleton CU)
contains the file name of another ("DWO") file with the debug info.
This can be a problem for remote compilation, as it will contain the
name of the file on the compilation server, not on the client.

To use Split DWARF with remote compilation, one needs to either

* make sure only relative paths are used, and mirror the build directory
  structure of the client on the server,
* inject the desired file name on the client directly.

Since llc already supports the latter solution, we're just copying that
over. We allow setting the actual output filename separately from the
value of the DW_AT_[GNU_]dwo_name attribute in the skeleton CU.

Fixes PR40276.

Reviewers: dblaikie, echristo, tejohnson

Reviewed By: dblaikie

Differential Revision: https://reviews.llvm.org/D59673

llvm-svn: 363496
2019-06-15 15:38:51 +00:00
Aaron Puchert 922759a63d [Clang] Rename -split-dwarf-file to -split-dwarf-output
Summary:
This is the first in a series of changes trying to align clang -cc1
flags for Split DWARF with those of llc. The unfortunate side effect of
having -split-dwarf-output for single file Split DWARF will disappear
again in a subsequent change.

The change is the result of a discussion in D59673.

Reviewers: dblaikie, echristo

Reviewed By: dblaikie

Differential Revision: https://reviews.llvm.org/D63130

llvm-svn: 363494
2019-06-15 14:07:43 +00:00
Gauthier Harnisch 83c7b61052 [clang] Add storage for APValue in ConstantExpr
Summary:
When using ConstantExpr we often need the result of the expression to be kept in the AST. Currently this is done on a by the node that needs the result and has been done multiple times for enumerator, for constexpr variables... . This patch adds to ConstantExpr the ability to store the result of evaluating the expression. no functional changes expected.

Changes:
 - Add trailling object to ConstantExpr that can hold an APValue or an uint64_t. the uint64_t is here because most ConstantExpr yield integral values so there is an optimized layout for integral values.
 - Add basic* serialization support for the trailing result.
 - Move conversion functions from an enum to a fltSemantics from clang::FloatingLiteral to llvm::APFloatBase. this change is to make it usable for serializing APValues.
 - Add basic* Import support for the trailing result.
 - ConstantExpr created in CheckConvertedConstantExpression now stores the result in the ConstantExpr Node.
 - Adapt AST dump to print the result when present.

basic* : None, Indeterminate, Int, Float, FixedPoint, ComplexInt, ComplexFloat,
the result is not yet used anywhere but for -ast-dump.

Reviewers: rsmith, martong, shafik

Reviewed By: rsmith

Subscribers: rnkovacs, hiraditya, dexonsmith, cfe-commits, llvm-commits

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D62399

llvm-svn: 363493
2019-06-15 10:24:47 +00:00
Gauthier Harnisch 0bb4d46b2b [clang] perform semantic checking in constant context
Summary:
Since the addition of __builtin_is_constant_evaluated the result of an expression can change based on whether it is evaluated in constant context. a lot of semantic checking performs evaluations with out specifying context. which can lead to wrong diagnostics.
for example:
```
constexpr int i0 = (long long)__builtin_is_constant_evaluated() * (1ll << 33); //#1
constexpr int i1 = (long long)!__builtin_is_constant_evaluated() * (1ll << 33); //#2
```
before the patch,  was diagnosed incorrectly and  wasn't diagnosed.
after the patch  is diagnosed as it should and  isn't.

Changes:
 - add a flag to Sema to passe in constant context mode.
 - in SemaChecking.cpp calls to Expr::Evaluate* are now done in constant context when they should.
 - in SemaChecking.cpp diagnostics for UB are not checked for in constant context because an error will be emitted by the constant evaluator.
 - in SemaChecking.cpp diagnostics for construct that cannot appear in constant context are not checked for in constant context.
 - in SemaChecking.cpp diagnostics on constant expression are always emitted because constant expression are always evaluated.
 - semantic checking for initialization of constexpr variables is now done in constant context.
 - adapt test that were depending on warning changes.
 - add test.

Reviewers: rsmith

Reviewed By: rsmith

Subscribers: cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D62009

llvm-svn: 363488
2019-06-15 08:32:56 +00:00
Ziang Wan af857b93df Add --print-supported-cpus flag for clang.
This patch allows clang users to print out a list of supported CPU models using
clang [--target=<target triple>] --print-supported-cpus

Then, users can select the CPU model to compile to using
clang --target=<triple> -mcpu=<model> a.c

It is a handy feature to help cross compilation.

llvm-svn: 363464
2019-06-14 21:42:21 +00:00
Francis Visoiu Mistrih 5501dda247 [Remarks][NFC] Improve testing and documentation of -foptimization-record-passes
This adds:

* documentation to the user manual
* nicer error message
* test for the error case
* test for the gold plugin

llvm-svn: 363463
2019-06-14 21:38:57 +00:00
Reid Kleckner 49b965079b Use unsigned for bitfields to avoid sign extension
llvm-svn: 363450
2019-06-14 20:19:29 +00:00
Richard Smith da70fc0c5f PR42071: Reject weird names for non-type template parameters.
Also reject default arguments appearing in invalid locations.

llvm-svn: 363447
2019-06-14 20:01:54 +00:00
Richard Smith 14059d2a13 Remove unused SK_LValueToRValue initialization step.
In addition to being unused and duplicating code, this was also wrong
(it didn't properly mark the operand as being potentially not odr-used).

This reinstates r363340, reverted in r363352.

llvm-svn: 363430
2019-06-14 17:46:39 +00:00
Sven van Haastregt e5bd808c3e Revert "[OpenCL] Move OpenCLBuiltins.td and remove unused include"
This reverts commit r363242 as it broke some builds with

  make[2]: *** No rule to make target 'ClangOpenCLBuiltinsImpl', needed by
  'tools/clang/lib/Sema/CMakeFiles/obj.clangSema.dir/SemaLookup.cpp.o'.

llvm-svn: 363376
2019-06-14 12:14:58 +00:00
Gauthier Harnisch 796ed03b84 [C++20] add Basic consteval specifier
Summary:
this revision adds Lexing, Parsing and Basic Semantic for the consteval specifier as specified by http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2018/p1073r3.html

with this patch, the consteval specifier is treated as constexpr but can only be applied to function declaration.

Changes:
 - add the consteval keyword.
 - add parsing of consteval specifier for normal declarations and lambdas expressions.
 - add the whether a declaration is constexpr is now represented by and enum everywhere except for variable because they can't be consteval.
 - adapt diagnostic about constexpr to print constexpr or consteval depending on the case.
 - add tests for basic semantic.

Reviewers: rsmith, martong, shafik

Reviewed By: rsmith

Subscribers: eraman, efriedma, rnkovacs, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D61790

llvm-svn: 363362
2019-06-14 08:56:20 +00:00
Nico Weber 3d02b895ed Revert 363295, it caused PR42276. Also revert follow-ups 363337, 363340.
Revert 363340 "Remove unused SK_LValueToRValue initialization step."
Revert 363337 "PR23833, DR2140: an lvalue-to-rvalue conversion on a glvalue of type"
Revert 363295 "C++ DR712 and others: handle non-odr-use resulting from an lvalue-to-rvalue conversion applied to a member access or similar not-quite-trivial lvalue expression."

llvm-svn: 363352
2019-06-14 04:05:17 +00:00
Stanislav Mekhanoshin 8a8131a3f6 [AMDGPU] gfx1010 wave32 clang support
Differential Revision: https://reviews.llvm.org/D63209

llvm-svn: 363341
2019-06-13 23:47:59 +00:00
Richard Smith aca017e802 Remove unused SK_LValueToRValue initialization step.
In addition to being unused and duplicating code, this was also wrong
(it didn't properly mark the operand as being potentially not odr-used).

llvm-svn: 363340
2019-06-13 23:47:42 +00:00
Dmitri Gribenko 31d68804fd Added AST matcher for ignoring elidable constructors
Summary: Added AST matcher for ignoring elidable move constructors

Reviewers: hokein, gribozavr

Reviewed By: hokein, gribozavr

Subscribers: cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D63149

Patch by Johan Vikström.

llvm-svn: 363262
2019-06-13 13:48:24 +00:00
Sven van Haastregt 95a9ee5e2f [OpenCL] Move OpenCLBuiltins.td and remove unused include
Patch by Pierre Gondois.

Differential revision: https://reviews.llvm.org/D62849

llvm-svn: 363242
2019-06-13 09:54:22 +00:00
Richard Smith 1bbad59379 For DR712: store on a MemberExpr whether it constitutes an odr-use.
llvm-svn: 363087
2019-06-11 17:50:36 +00:00
Richard Smith 715f7a1bd0 For DR712: store on a DeclRefExpr whether it constitutes an odr-use.
Begin restructuring to support the forms of non-odr-use reference
permitted by DR712.

llvm-svn: 363086
2019-06-11 17:50:32 +00:00
Nikolai Kosjar 8edd8da487 [libclang] Allow skipping warnings from all included files
Depending on the included files and the used warning flags, e.g. -
Weverything, a huge number of warnings can be reported for included
files. As processing that many diagnostics comes with a performance
impact and not all clients are interested in those diagnostics, add a
flag to skip them.

Differential Revision: https://reviews.llvm.org/D48116

llvm-svn: 363067
2019-06-11 14:14:24 +00:00
Pengfei Wang 244062eece [X86] Enable intrinsics that convert float and bf16 data to each other
Scalar version :
_mm_cvtsbh_ss , _mm_cvtness_sbh

Vector version:
_mm512_cvtpbh_ps , _mm256_cvtpbh_ps
_mm512_maskz_cvtpbh_ps , _mm256_maskz_cvtpbh_ps
_mm512_mask_cvtpbh_ps , _mm256_mask_cvtpbh_ps

Patch by Shengchen Kan (skan)

Differential Revision: https://reviews.llvm.org/D62363

llvm-svn: 363018
2019-06-11 01:17:28 +00:00
Reid Kleckner e78333a010 Require stdcall etc parameters to be complete on ODR use
Functions using stdcall, fastcall, or vectorcall with C linkage mangle
in the size of the parameter pack. Calculating the size of the pack
requires the parameter types to complete, which may require template
instantiation.

Previously, we would crash during IRgen when requesting the size of
incomplete or uninstantiated types, as in this reduced example:
  struct Foo;
  void __fastcall bar(struct Foo o);
  void (__fastcall *fp)(struct Foo) = &bar;

Reported in Chromium here: https://crbug.com/971245

Differential Revision: https://reviews.llvm.org/D62975

llvm-svn: 363000
2019-06-10 22:53:12 +00:00
David Blaikie 8472fa6c54 DebugInfo: Add support for 'nodebug' attribute on typedefs and alias templates
Seems like a logical extension to me - and of interest because it might
help reduce the debug info size of libc++ by applying this attribute to
type traits that have a disproportionate debug info cost compared to the
benefit (& possibly harm/confusion) they cause users.

llvm-svn: 362856
2019-06-08 00:01:21 +00:00
Keno Fischer 6f48c07620 [analyzer] Add werror flag for analyzer warnings
Summary:
We're using the clang static analyzer together with a number of
custom analyses in our CI system to ensure that certain invariants
are statiesfied for by the code every commit. Unfortunately, there
currently doesn't seem to be a good way to determine whether any
analyzer warnings were emitted, other than parsing clang's output
(or using scan-build, which then in turn parses clang's output).
As a simpler mechanism, simply add a `-analyzer-werror` flag to CC1
that causes the analyzer to emit its warnings as errors instead.
I briefly tried to have this be `Werror=analyzer` and make it go
through that machinery instead, but that seemed more trouble than
it was worth in terms of conflicting with options to the actual build
and special cases that would be required to circumvent the analyzers
usual attempts to quiet non-analyzer warnings. This is simple and it
works well.

Reviewed-By: NoQ, Szelethusw
Differential Revision: https://reviews.llvm.org/D62885

llvm-svn: 362855
2019-06-07 23:34:00 +00:00
Peter Collingbourne e08e68de21 Driver, IRGen: Set partitions on GlobalValues according to -fsymbol-partition flag.
Differential Revision: https://reviews.llvm.org/D62636

llvm-svn: 362829
2019-06-07 19:10:08 +00:00
Pengfei Wang 30bcda86db [X86] -march=cooperlake (clang)
Support intel -march=cooperlake in clang

Patch by Shengchen Kan (skan)

Differential Revision: https://reviews.llvm.org/D62835

llvm-svn: 362781
2019-06-07 08:53:37 +00:00
Richard Smith 84be998497 Factor out duplicated code building a MemberExpr and marking it
referenced.

This reinstates r362563, reverted in r362597.

llvm-svn: 362757
2019-06-06 23:24:18 +00:00
Richard Smith dcf17ded66 Convert MemberExpr creation and serialization to work the same way as
most / all other Expr subclasses.

This reinstates r362551, reverted in r362597, with a fix to a bug that
caused MemberExprs to sometimes have a null FoundDecl after a round-trip
through an AST file.

llvm-svn: 362756
2019-06-06 23:24:15 +00:00
Francois Ferrand e8a301f87f clang-format: better handle namespace macros
Summary:
Other macros are used to declare namespaces, and should thus be handled
similarly. This is the case for crpcut's TESTSUITE macro, or for
unittest-cpp's SUITE macro:

      TESTSUITE(Foo) {
      TEST(MyFirstTest) {
        assert(0);
      }
      } // TESTSUITE(Foo)

This patch deals with this cases by introducing a new option to specify
lists of namespace macros. Internally, it re-uses the system already in
place for foreach and statement macros, to ensure there is no impact on
performance.

Reviewers: krasimir, djasper, klimek

Reviewed By: klimek

Subscribers: acoomans, cfe-commits, klimek

Tags: #clang

Differential Revision: https://reviews.llvm.org/D37813

llvm-svn: 362740
2019-06-06 20:06:23 +00:00
Yitzhak Mandelbaum 2e4a628c06 [LibTooling] Add insert/remove convenience functions for creating `ASTEdit`s.
Summary: `change()` is an all purpose function; the revision adds simple shortcuts for the specific operations of inserting (before/after) or removing source.

Reviewers: ilya-biryukov

Subscribers: cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D62621

llvm-svn: 362707
2019-06-06 14:20:29 +00:00
Pengfei Wang 3a29f7c99c [X86] Add ENQCMD instructions
For more details about these instructions, please refer to the latest
ISE document:
https://software.intel.com/en-us/download/intel-architecture-instruction-set-extensions-programming-reference.

Patch by Tianqing Wang (tianqing)

Differential Revision: https://reviews.llvm.org/D62282

llvm-svn: 362685
2019-06-06 08:28:42 +00:00
Jan Korous a3701caad8 [clang-format][NFC] Fix BS_Allman style example in the header docs are generated from
Differential Revision: https://reviews.llvm.org/D61729

llvm-svn: 362646
2019-06-05 20:59:48 +00:00
Erich Keane da59652c1b Avoid using NoThrow Exception Specifier in non-C++ Modes.
As reported in https://bugs.llvm.org/show_bug.cgi?id=42113, there are a
number of locations in Clang where it is assumed that exception
specifications are only valid in C++ mode. Since the original
justification for the NoThrow Exception Specifier Type was C++ related,
this patch just makes C mode use the attribute-based nothrow handling.

Additionally, I noticed that the handling of non-prototype functions
regressed the behavior of the nothrow attribute, in part because it is
was listed in the function type macro(which I did in the previous
patch).  In reality, it should only be doing so in a conditional nature,
so this patch removes it there and puts it directly in the switch to be
handled correctly.

llvm-svn: 362607
2019-06-05 14:10:39 +00:00
Anastasia Stulova 5145b1e442 [Sema] Prevent binding incompatible addr space ref to temporaries
References to arbitrary address spaces can't always be bound to
temporaries. This change extends the reference binding logic to
check that the address space of a temporary can be implicitly
converted to the address space in a reference when temporary
materialization is performed.

Differential Revision: https://reviews.llvm.org/D61318

llvm-svn: 362604
2019-06-05 14:03:34 +00:00
Benjamin Kramer 9b2b8ad8b1 Revert "Factor out duplicated code building a MemberExpr and marking it" and "Convert MemberExpr creation and serialization to work the same way as"
This reverts commits r362551 and r362563. Crashes during modules selfhost.

llvm-svn: 362597
2019-06-05 11:46:57 +00:00
Nemanja Ivanovic 6321c68065 Initial support for vectorization using MASSV (IBM MASS vector library)
Part 2 (the Clang portion) of D59881.

This patch (first of two patches) enables the vectorizer to recognize the
IBM MASS vector library routines. This patch specifically adds support for
recognizing the -vector-library=MASSV option, and defines mappings from IEEE
standard scalar math functions to generic PowerPC MASS vector counterparts.
For instance, the generic PowerPC MASS vector entry for double-precision
cbrt function is __cbrtd2_massv.

The second patch will further lower the generic PowerPC vector entries to
PowerPC subtarget-specific entries.
For instance, the PowerPC generic entry cbrtd2_massv is lowered to
cbrtd2_P9 for Power9 subtarget.

The overall support for MASS vector library is presented as such in two patches
for ease of review.

Patch by Jeeva Paudel.

Differential revision: https://reviews.llvm.org/D59881

llvm-svn: 362571
2019-06-05 01:57:57 +00:00
Richard Smith 8ca5455764 Factor out duplicated code building a MemberExpr and marking it
referenced.

llvm-svn: 362563
2019-06-05 00:21:47 +00:00
Richard Smith c32ef4bc0b Convert MemberExpr creation and serialization to work the same way as
most / all other Expr subclasses.

llvm-svn: 362551
2019-06-04 21:29:28 +00:00
Richard Smith 7dcd73340b Factor out repeated code to build a DeclRefExpr and mark it referenced.
llvm-svn: 362537
2019-06-04 18:30:46 +00:00
Richard Smith 7bf8f6fa8a PR42104: Support instantiations of lambdas that implicitly capture
packs.

Two changes:
 * Track odr-use via FunctionParmPackExprs to properly handle dependent
   odr-uses of packs in generic lambdas.
 * Do not instantiate implicit captures; instead, regenerate them by
   instantiating the body of the lambda. This is necessary to
   distinguish between cases where only one element of a pack is
   captured and cases where the entire pack is captured.

This reinstates r362358 (reverted in r362375) with a fix for an
uninitialized variable use in UpdateMarkingForLValueToRValue.

llvm-svn: 362531
2019-06-04 17:17:20 +00:00
Alex Lorenz 6e2d36b60b Add clang source minimizer that reduces source to directives
that might affect the dependency list for a compilation

This commit introduces a dependency directives source minimizer to clang
that minimizes header and source files to the minimum necessary preprocessor
directives for evaluating includes. It reduces the source down to #define, #include,

The source minimizer works by lexing the input with a custom fast lexer that recognizes
the preprocessor directives it cares about, and emitting those directives in the minimized source.
It ignores source code, comments, and normalizes whitespace. It gives up and fails if seems
any directives that it doesn't recognize as valid (e.g. #define 0).

In addition to the source minimizer this patch adds a
-print-dependency-directives-minimized-source CC1 option that allows you to invoke the minimizer
from clang directly.

Differential Revision: https://reviews.llvm.org/D55463

llvm-svn: 362459
2019-06-03 22:59:17 +00:00