llvm-project/clang
Michael Kruse ae6b400002 [Preprocessor] Implement -fminimize-whitespace.
This patch adds the -fminimize-whitespace with the following effects:

 * If combined with -E, remove as much non-line-breaking whitespace as
   possible.

 * If combined with -E -P, removes as much whitespace as possible,
   including line-breaks.

The motivation is to reduce the amount of insignificant changes in the
preprocessed output with source files where only whitespace has been
changed (add/remove comments, clang-format, etc.) which is in particular
useful with ccache.

A patch for ccache for using this flag has been proposed to ccache as well:
https://github.com/ccache/ccache/pull/815, which will use
-fnormalize-whitespace when clang-13 has been detected, and additionally
uses -P in "unify_mode". ccache already had a unify_mode in an older
version which was removed because of problems that using the
preprocessor itself does not have (such that the custom tokenizer did
not recognize C++11 raw strings).

This patch slightly reorganizes which part is responsible for adding
newlines that are required for semantics. It is now either
startNewLineIfNeeded() or MoveToLine() but never both; this avoids the
ShouldUpdateCurrentLine workaround and avoids redundant lines being
inserted in some cases. It also fixes a mandatory newline not inserted
after a _Pragma("...") that is expanded into a #pragma.

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D104601
2021-07-25 23:30:57 -05:00
..
INPUTS
bindings
cmake [ifs][elfabi] Merge llvm-ifs/elfabi tools 2021-07-19 11:23:19 -07:00
docs [Preprocessor] Implement -fminimize-whitespace. 2021-07-25 23:30:57 -05:00
examples
include [Preprocessor] Implement -fminimize-whitespace. 2021-07-25 23:30:57 -05:00
lib [Preprocessor] Implement -fminimize-whitespace. 2021-07-25 23:30:57 -05:00
runtime Prepare Compiler-RT for GnuInstallDirs, matching libcxx, document all 2021-07-13 15:21:41 +00:00
test [Preprocessor] Implement -fminimize-whitespace. 2021-07-25 23:30:57 -05:00
tools [clang] Introduce SourceLocation::[U]IntTy typedefs. 2021-07-21 10:45:46 +01:00
unittests [clang][AST] Add support for DecompositionDecl to ASTImporter. 2021-07-22 13:09:42 +02:00
utils [Clang][RISCV] Support half-precision floating point for RVV intrinsics. 2021-07-19 23:17:01 +08:00
www Partially implement P1401R5 (Narrowing contextual conversions to bool) 2021-07-12 08:06:27 -04:00
.clang-format
.clang-tidy .clang-tidy: Disable misc-no-recursion in general/across the monorepo 2021-06-08 08:31:33 -07:00
.gitignore
CMakeLists.txt
CODE_OWNERS.TXT
INSTALL.txt
LICENSE.TXT
ModuleInfo.txt
NOTES.txt
README.txt

README.txt

//===----------------------------------------------------------------------===//
// C Language Family Front-end
//===----------------------------------------------------------------------===//

Welcome to Clang.  This is a compiler front-end for the C family of languages
(C, C++, Objective-C, and Objective-C++) which is built as part of the LLVM
compiler infrastructure project.

Unlike many other compiler frontends, Clang is useful for a number of things
beyond just compiling code: we intend for Clang to be host to a number of
different source-level tools.  One example of this is the Clang Static Analyzer.

If you're interested in more (including how to build Clang) it is best to read
the relevant web sites.  Here are some pointers:

Information on Clang:             http://clang.llvm.org/
Building and using Clang:         http://clang.llvm.org/get_started.html
Clang Static Analyzer:            http://clang-analyzer.llvm.org/
Information on the LLVM project:  http://llvm.org/

If you have questions or comments about Clang, a great place to discuss them is
on the Clang development mailing list:
  http://lists.llvm.org/mailman/listinfo/cfe-dev

If you find a bug in Clang, please file it in the LLVM bug tracker:
  http://llvm.org/bugs/