Google Git
Sign in
chromium / external / github.com / llvm / llvm-project.git / 4d42e16eb8f7bb1484a1970324aa3391809188de
commit4d42e16eb8f7bb1484a1970324aa3391809188de[log] [tgz]
authorpeter klausler <[email protected]>Thu Jul 22 16:47:37 2021
committerpeter klausler <[email protected]>Sat Jul 24 01:23:26 2021
treee524cdff302625f7a11c772a6f5538a2f9c94cc1
parente093cbb7ae1448379cad5520db5dfa5cf0b06bdf [diff]
[flang] runtime: fix problems with I/O around EOF & delimited characters

When a WRITE overwrites an endfile record, we need to forget
that there was an endfile record.  When doing a BACKSPACE
after an explicit ENDFILE statement, the position afterwards
must be upon the endfile record.

Attempts to join list-directed delimited character input across
record boundaries was due to a bad reading of the standard
and has been deleted, now that the requirements are better understood.
This problem would cause a read attempt past EOF if a delimited
character input value was at the end of a record.

It turns out that delimited list-directed (and NAMELIST) character
output is required to emit contiguous doubled instances of the
delimiter character when it appears in the output value.  When
fixed-size records are being emitted, as is the case with internal
output, this is not possible when the problematic character falls
on the last position of a record.  No two other Fortran compilers
do the same thing in this situation so there is no good precedent
to follow.

Because it seems least wrong, with this patch we now emit one copy
of the delimiter as the last character of the current record and
another as the first character of the next record.  (The
second-least-wrong alternative might be to flag a runtime error,
but that seems harsh since it's not an explicit error in the standard,
and the output may not have to be usable later as input anyway.)
Consequently, the output is not suitable for use as list-directed or
NAMELIST input.

If a later standard were to clarify this case, this behavior will of
course change as needed to conform.

Differential Revision: https://reviews.llvm.org/D106695
5 files changed
tree: e524cdff302625f7a11c772a6f5538a2f9c94cc1
  1. .github/
  2. clang/
  3. clang-tools-extra/
  4. compiler-rt/
  5. cross-project-tests/
  6. flang/
  7. libc/
  8. libclc/
  9. libcxx/
  10. libcxxabi/
  11. libunwind/
  12. lld/
  13. lldb/
  14. llvm/
  15. mlir/
  16. openmp/
  17. parallel-libs/
  18. polly/
  19. pstl/
  20. runtimes/
  21. utils/
  22. .arcconfig
  23. .arclint
  24. .clang-format
  25. .clang-tidy
  26. .git-blame-ignore-revs
  27. .gitignore
  28. .mailmap
  29. CONTRIBUTING.md
  30. README.md
  31. SECURITY.md
README.md

The LLVM Compiler Infrastructure

This directory and its sub-directories contain source code for LLVM, a toolkit for the construction of highly optimized compilers, optimizers, and run-time environments.

The README briefly describes how to get started with building LLVM. For more information on how to contribute to the LLVM project, please take a look at the Contributing to LLVM guide.

Getting Started with the LLVM System

Taken from https://llvm.org/docs/GettingStarted.html.

Overview

Welcome to the LLVM project!

The LLVM project has multiple components. The core of the project is itself called “LLVM”. This contains all of the tools, libraries, and header files needed to process intermediate representations and convert them into object files. Tools include an assembler, disassembler, bitcode analyzer, and bitcode optimizer. It also contains basic regression tests.

C-like languages use the Clang front end. This component compiles C, C++, Objective-C, and Objective-C++ code into LLVM bitcode -- and from there into object files, using LLVM.

Other components include: the libc++ C++ standard library, the LLD linker, and more.

Getting the Source Code and Building LLVM

The LLVM Getting Started documentation may be out of date. The Clang Getting Started page might have more accurate information.

This is an example work-flow and configuration to get and build the LLVM source:

  1. Checkout LLVM (including related sub-projects like Clang):

    • git clone https://github.com/llvm/llvm-project.git

    • Or, on windows, git clone --config core.autocrlf=false https://github.com/llvm/llvm-project.git

  2. Configure and build LLVM and Clang:

    • cd llvm-project

    • cmake -S llvm -B build -G <generator> [options]

      Some common build system generators are:

      • Ninja --- for generating Ninja build files. Most llvm developers use Ninja.
      • Unix Makefiles --- for generating make-compatible parallel makefiles.
      • Visual Studio --- for generating Visual Studio projects and solutions.
      • Xcode --- for generating Xcode projects.

      Some Common options:

      • -DLLVM_ENABLE_PROJECTS='...' --- semicolon-separated list of the LLVM sub-projects you'd like to additionally build. Can include any of: clang, clang-tools-extra, libcxx, libcxxabi, libunwind, lldb, compiler-rt, lld, polly, or cross-project-tests.

        For example, to build LLVM, Clang, libcxx, and libcxxabi, use -DLLVM_ENABLE_PROJECTS="clang;libcxx;libcxxabi".

      • -DCMAKE_INSTALL_PREFIX=directory --- Specify for directory the full path name of where you want the LLVM tools and libraries to be installed (default /usr/local).

      • -DCMAKE_BUILD_TYPE=type --- Valid options for type are Debug, Release, RelWithDebInfo, and MinSizeRel. Default is Debug.

      • -DLLVM_ENABLE_ASSERTIONS=On --- Compile with assertion checks enabled (default is Yes for Debug builds, No for all other build types).

    • cmake --build build [-- [options] <target>] or your build system specified above directly.

      • The default target (i.e. ninja or make) will build all of LLVM.

      • The check-all target (i.e. ninja check-all) will run the regression tests to ensure everything is in working order.

      • CMake will generate targets for each tool and library, and most LLVM sub-projects generate their own check-<project> target.

      • Running a serial build will be slow. To improve speed, try running a parallel build. That's done by default in Ninja; for make, use the option -j NNN, where NNN is the number of parallel jobs, e.g. the number of CPUs you have.

    • For more information see CMake

Consult the Getting Started with LLVM page for detailed information on configuring and compiling LLVM. You can visit Directory Layout to learn about the layout of the source code tree.