[all-commits] [llvm/llvm-project] 577add: [Support/Path] Add path::is_absolute_gnu
Vinicius Tinti via All-commits
all-commits at lists.llvm.org
Wed Sep 23 10:03:30 PDT 2020
Branch: refs/heads/master
Home: https://github.com/llvm/llvm-project
Commit: 577adda54f075b256007ed4fa80c9988a0642a87
https://github.com/llvm/llvm-project/commit/577adda54f075b256007ed4fa80c9988a0642a87
Author: Vinicius Tinti <viniciustinti at gmail.com>
Date: 2020-09-23 (Wed, 23 Sep 2020)
Changed paths:
M llvm/include/llvm/Support/Path.h
M llvm/lib/Support/Path.cpp
M llvm/unittests/Support/Path.cpp
Log Message:
-----------
[Support/Path] Add path::is_absolute_gnu
Implements IS_ABSOLUTE_PATH from GNU tools.
C++17 is_absolute behavior is different the from the behavior defined by GNU
tools.
According to cppreference.com, C++17 states: "An absolute path is a path
that unambiguously identifies the location of a file without reference
to an additional starting location."
In other words, the rules are:
1. POSIX style paths with nonempty root directory are absolute.
2. Windows style paths with nonempty root name and root directory are
absolute.
3. No other paths are absolute.
GNU rules are:
1. Paths starting with a path separator are absolute.
2. Windows style paths are also absolute if they start with a character
followed by ':'.
3. No other paths are absolute.
On Windows style the path "C:\Users\Default" has "C:" as root name and "\"
as root directory.
Hence "C:" on Windows is absolute under GNU rules and not absolute under
C++17 because it has no root directory. Likewise "/" and "\" on Windows are
absolute under GNU and are not absolute under C++17 due to empty root name.
Related to PR46368.
Differential Revision: https://reviews.llvm.org/D87667
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