Use ELF headers vendored in `Utilities/cmelf` to get the ELF constants
and types. Using the same ELF definition header for all compilation
targets allows removing some #ifdefs depending on the host OS since we
know all required ELF constants will always be present. To reduce the
size of this commit, the CMake_USE_ELF_PARSER definite will be removed
in a separate commit.
This allows me to use CMAKE_BUILD_WITH_INSTALL_RPATH=False and the Ninja
generator on macOS, whereas before it would always give me the following
error message (despite cross-compiling for an ELF-based platform):
```
The install of the <name> target requires changing an RPATH from
the build tree, but this is not supported with the Ninja generator unless
on an ELF-based platform. The CMAKE_BUILD_WITH_INSTALL_RPATH variable may
be set to avoid this relinking step.
```
DT_MIPS_RLD_MAP_REL is a machine-speicific dynamic tag, so other
architectures could re-use the value of 0x70000035 to mean something
else. Before using DT_MIPS_RLD_MAP_REL, we have to check that the ELF
file is actually has a e_machine of EM_MIPS.
These headers will be used to provide the ELF parsing code on all host
operating systems (including those that don't have an ELF header, e.g.
macOS). This will also allow removing various OS-dependent #ifdefs from
the cmELF code. Add a script that was used to automate this import.
Co-authored-by: Alex Richardson <Alexander.Richardson@cl.cam.ac.uk>
I noticed that I wasn't getting any compiler warnings when testing my
merge requests locally. Turns out this happens because I am compiling
using Clang rather than GCC, so no warning flags are added to the build.
d06a9bdf3a enabled warnings by default
for GCC > 4.2, but Clang supports them too. This has been the case
since at least Clang 3.0 (I couldn't test any older versions on
godbolt.org). For AppleClang, we can also assume that the warning flags
are supported. According to Wikipedia Clang became the default
compiler starting with Xcode 4.2, and the table on
https://trac.macports.org/wiki/XcodeVersionInfo, states that XCode
4.2 Clang was based on upstream Clang 3.0, which supports all the
warning flags.
The warning flags are currently not added when compiling with clang-cl
since this exposes some pre-existing warnings that need to be fixed first.
f29e1874ad Compiler/MSVC: use the `-external:I` flag for system includes
5a5c85dffd Tests/IncludeDirectories: support MSVC in system include tests
399a3204bb Tests/IncludeDirectories: align sibling predicates
20ab49193b Tests/IncludeDirectories: factor out applying flags to targets
809f7b0c3a Tests/IncludeDirectories: fix copy pasta for otherlib
b094324948 Tests/IncludeDirectories: Include system headers via angle brackets
8f63f3b04e cmVisualStudio10TargetGenerator: remove unused variable
Acked-by: Kitware Robot <kwrobot@kitware.com>
Acked-by: Julien Waechter <greenjava@gmail.com>
Acked-by: DE-VS wenglor <devs.wenglor@gmail.com>
Merge-request: !4766
Alex Richardson