For historic reasons, the behavior of .align differs between targets.
Fortunately, there are alternatives, .p2align and .balign, which make the
interpretation of the parameter explicit, and which behave consistently across
targets.
This patch teaches MC to use .p2align instead of .align, so that people reading
code for multiple architectures don't have to remember which way each platform
does its .align directive.
Differential Revision: http://reviews.llvm.org/D16549
llvm-svn: 258750
than on MipsSubtargetInfo.
This required a bit of massaging in the MC level to handle this since
MC is a) largely a collection of disparate classes with no hierarchy,
and b) there's no overarching equivalent to the TargetMachine, instead
only the subtarget via MCSubtargetInfo (which is the base class of
TargetSubtargetInfo).
We're now storing the ABI in both the TargetMachine level and in the
MC level because the AsmParser and the TargetStreamer both need to
know what ABI we have to parse assembly and emit objects. The target
streamer has a pointer to the one in the asm parser and is updated
when the asm parser is created. This is fragile as the FIXME comment
notes, but shouldn't be a problem in practice since we always
create an asm parser before attempting to emit object code via the
assembler. The TargetMachine now contains the ABI so that the DataLayout
can be constructed dependent upon ABI.
All testcases have been updated to use the -target-abi command line
flag so that we can set the ABI without using a subtarget feature.
Should be no change visible externally here.
llvm-svn: 227102
Summary:
I had difficulty finding tests for the N32 and N64 ABI so I've added a
collection of calling convention tests based on the document MIPS ABIs
Described (MD00305), the MIPSpro N32 Handbook, and the SYSV ABI. Where the
documents/implementations disagree, I've used GCC to resolve the conflict.
A few interesting details:
* For N32, LLVM uses 64-bit pointers when saving $ra despite pointers being
32-bit. I've yet to find a supporting statement in the ABI documentation but
the current behaviour matches GCC.
* For O32, the non-variable portion of a varargs argument list is also subject
to the rule that floating-point is passed via GPR's (on N32/N64 only the
variable portion is subject to this rule). This agrees with GCC's behaviour
and the SYSV ABI but contradicts part of the MIPSpro N32 Handbook which talks about O32's behaviour.
* The N32 implementation has the wrong callee-saved register list.
(I already have a fix for this but will commit it as a follow-up).
I've left RUN-TODO lines in for O32 on MIPS64. I don't plan to support this case
for now but we should revisit it.
Reviewers: matheusalmeida, vmedic
Reviewed By: matheusalmeida
Differential Revision: http://reviews.llvm.org/D3339
llvm-svn: 206370
Daniel Sanders