ABI lowering for winabi was incorrectly using a Kl cls when emitting
Ostorel, which in turn was causing isel to fail to lower large constants
in to temporaries ( https://c9x.me/git/qbe.git/tree/amd64/isel.c#n107 )
when necessary.
(This should be applied on the 'winabi' branch.)
In the presence of the hidden arg for return-by-value, the
registers used for natural arguments were incorrect.
(This should be applied on the 'winabi' branch.)
This is an implementation of the Windows ABI. It supports most features
(struct passing/returning, varargs, env). TLS is not yet supported.
This patch does not actually port QBE to Windows, it only allows QBE to
generate correct asm to target Windows. As a result, testing is
accomplished on a Linux host, by using a cross-compiling toolchain, and
running the resulting binaries by using wine. See:
TARGET=amd64_win tools/test.sh all
A few cross-platform tests were changed from 'long' to 'long long' in
driver code because long in C does not match the size of a QBE 'l' on
Windows.
On x86_64, direct calls are always PC-relative. This means that
in order to call an absolute address, the call must be indirect.
To accomplish this, update fixarg to introduce a temporary before
emitting.
Replacement of tiny conditional jump graphlets with
conditional move instructions.
Currently enabled only for x86. Arm64 support using cselXX
will be essentially identical.
Adds (internal) frontend sel0/sel1 ops with flag-specific
backend xselXX following jnz implementation pattern.
Testing: standard QBE, cproc, harec, hare, roland
- Many stylistic nits.
- Removed blkmerge().
- Some minor bug fixes.
- GCM reassoc is now "sink"; a pass that
moves trivial ops in their target block
with the same goal of reducing register
pressure, but starting from instructions
that benefit from having their inputs
close.
Scratching an itch - avoid unnecesary re-allocation in idup()
which is called often in the optimisation chain.
Blk::ins is reallocated in xxx_abi() - needs further fiddling.
when applying a custom set of CFLAGS under clang that does not include
-std=c99, asm is treated as a keyword and as such can not be used as an
identifier. this prevents the issue by renaming the offending variables.
Support "file" and "loc" directives. "file" takes a string (a file name)
assigns it a number, sets the current file to that number and records
the string for later. "loc" takes a single number and outputs location
information with a reference to the current file.
Crashing loads of uninitialized memory
proved to be a problem when implementing
unions using qbe. This patch introduces
a new UNDEF Ref to represent data that is
known to be uninitialized. Optimization
passes can make use of it to eliminate
some code. In the last compilation stages,
UNDEF is treated as the constant 0xdeaddead.
It is handy to express when
the end of a block cannot be
reached. If a hlt terminator
is executed, it traps the
program.
We don't go the llvm way and
specify execution semantics as
undefined behavior.
Symbols are a useful abstraction
that occurs in both Con and Alias.
In this patch they get their own
struct. This new struct packages
a symbol name and a type; the type
tells us where the symbol name
must be interpreted (currently, in
gobal memory or in thread-local
storage).
The refactor fixed a bug in
addcon(), proving the value of
packaging symbol names with their
type.
It is quite similar to arm64_apple.
Probably, the call that needs to be
generated also provides extra
invariants on top of the regular
abi, but I have not checked that.
Clang generates code that is a bit
neater than qbe's because, on x86,
a load can be fused in a call
instruction! We do not bother with
supporting these since we expect
only sporadic use of the feature.
For reference, here is what clang
might output for a store to the
second entry of a thread-local
array of ints:
movq _x@TLVP(%rip), %rdi
callq *(%rdi)
movl %ecx, 4(%rax)
The general idea is to give abis a
chance to talk before we've done all
the optimizations. Currently, all
targets eliminate {par,arg,ret}{sb,ub,...}
during this pass. The forthcoming
arm64_apple will, however, insert
proper extensions during abi0.
Moving forward abis can, for example,
lower small-aggregates passing there
so that memory optimizations can
interact better with function calls.
apple support is more than assembly syntax
in case of arm64 machines, and apple syntax
is currently useless in all cases but amd64;
rather than having a -G option that only
makes sense with amd64, we add a new target
amd64_apple