Reduce the likelihood of x64/x86-64 changes breaking the build on other arches
The file compiler/nativeGen/X86/Regs.hs is causing rather a lot of trouble for people on CPUs other than x86 and x86-86. Problems like these two:
The problem is caused by code like this:
# if i386_TARGET_ARCH
someFuncion = .....
# elif x86_64_TARGET_ARCH
someFuncion = .....
# else
someFuncion = .....
# endifCode like this becomes problematic (ie fails to compile on non x86/x86-64) under a number of related obscure conditions like:
- someFunction is exported from the module, but the #else part is forgotten, causing the compile to fail.
- someFunction has a function signature but the #else part is forgotten resulting in a signature with no implmentation.
- someFunction uses an import module on x86 or x86-64 that isn't used in the #else cases causing a compile error with -Werror (eg validate).
Fortunately, I think there is a simple solution to this. If we chose one of these arches to be the default (say x86-64) then all instances of the above pattern could be rewritten as:
# if i386_TARGET_ARCH
someFuncion = .....
# else
someFuncion = .....
# endifmeaning that on PowerPC and ARM, the x86 code generator only generates code for x86-64 (the default), but makes the code simpler in general and easier to get right.
I am currently working on a patch which provides this functionality.
Trac metadata
| Trac field | Value |
|---|---|
| Version | 7.5 |
| Type | Task |
| TypeOfFailure | OtherFailure |
| Priority | normal |
| Resolution | Unresolved |
| Component | Compiler |
| Test case | |
| Differential revisions | |
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| Related | |
| Blocking | |
| CC | |
| Operating system | |
| Architecture |