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Diffstat (limited to 'butl/triplet')
| -rw-r--r-- | butl/triplet | 97 |
1 files changed, 97 insertions, 0 deletions
diff --git a/butl/triplet b/butl/triplet new file mode 100644 index 0000000..c18368c --- /dev/null +++ b/butl/triplet @@ -0,0 +1,97 @@ +// file : butl/triplet -*- C++ -*- +// copyright : Copyright (c) 2014-2016 Code Synthesis Ltd +// license : MIT; see accompanying LICENSE file + +#ifndef BUTL_TRIPLET +#define BUTL_TRIPLET + +#include <string> + +namespace butl +{ + // This is the ubiquitous 'target triplet' that loosely has the CPU-VENDOR-OS + // form which, these days, quite often takes the CPU-VENDOR-OS-ABI form. Plus + // some fields can sometimes be omitted. This looseness makes it hard to base + // any kind of decisions on the triplet without canonicalizing it and then + // splitting it into components. the way we are going to split it is like + // this: + // + // CPU + // + // This one is reasonably straightforward. Note that we always expect at + // least two components with the first being the CPU. In other words, we + // don't try to guess what just 'mingw32' might mean like config.sub does. + // + // VENDOR + // + // This can be a machine vendor as in i686-apple-darwin8, a toolchain vendor + // as in i686-lfs-linux-gnu, or something else as in arm-softfloat-linux-gnu. + // Just as we think vendor is pretty irrelevant and can be ignored, comes + // MinGW-W64 and calls itself *-w64-mingw32. While it is tempting to + // attribute w64 to OS-ABI, the MinGW-W64 folks insist it is a (presumably + // toolchain) vendor. + // + // To make thing more regular we also convert the information-free vendor + // names 'pc', 'unknown' and 'none' to the empty name. + // + // OS/KERNEL-OS/OS-ABI + // + // This is where things get really messy and instead of trying to guess, we + // call the entire thing SYSTEM. Except, in certain cases, we factor out the + // trailing version, again, to make SYSTEM easier to compare to. For example, + // *-darwin14.5.0 becomes 'darwin' and '14.5.0'. + // + // Again, to make things more regular, if the first component in SYSTEM is + // none, then it is removed (so *-none-eabi becomes just 'eabi'). + // + // Values for two-component systems (e.g., linux-gnu) that don't specify + // VENDOR explicitly are inherently ambiguous: is 'linux' VENDOR or part of + // SYSTEM? The only way to handle this is to recognize their specific names + // as special cases and this is what we do for some of the more common + // ones. The alternative would be to first run such names through config.sub + // which adds explicit VENDOR and this could be a reasonable fallback + // strategy for (presumably less common) cases were we don't split things + // correctly. + // + // Note also that the version splitting is only done for certain, + // commonly-used targets. + // + // Some examples of canonicalization and splitting: + // + // x86_64-apple-darwin14.5.0 x86_64 apple darwin 14.5.0 + // x86_64-unknown-freebsd10.2 x86_64 freebsd 10.2 + // i686-elf i686 elf + // arm-eabi arm eabi + // arm-none-eabi arm eabi + // arm-none-linux-gnueabi arm linux-gnueabi + // arm-softfloat-linux-gnu arm softfloat linux-gnu + // i686-pc-mingw32 i686 mingw32 + // i686-w64-mingw32 i686 w64 mingw32 + // i686-lfs-linux-gnu i686 lfs linux-gnu + // x86_64-unknown-linux-gnu x86_64 linux-gnu + // x86_64-linux-gnux32 x86_64 linux-gnux32 + // + // References: + // + // 1. The libtool repository contains the PLATFORM file that lists many known + // triplets. + // + // 2. LLVM has the Triple class with similar goals. + // + struct triplet + { + std::string cpu; + std::string vendor; + std::string system; + std::string version; + + // Parse the triplet optionally returning the canonicalized string. Throw + // std::invalid_argument if the triplet is not recognizable. + // + explicit + triplet (const std::string&, std::string* canon = nullptr); + triplet (const std::string& s, std::string& canon): triplet (s, &canon) {} + }; +}; + +#endif // BUTL_TRIPLET |