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.
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.
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.
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)
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
Reported by Alessandro Mantovani.
Unlikely to be hit in practice
because we don't add addresses to
addresses.
type :biggie = { l, l, l }
function $repro(:biggie %p) {
@start
%x =l add %p, $a
storew 42, %x
ret
}
We now emit correct code when the user
refers to a specific constant address.
I also made some comments clearer in
the instruction selection pass and got
rid of some apparently useless code.
There is no flavor of mov which can set 8 bytes
of memory to a constant not representable as an
int32. The solution is simply to emit two movs
of 4 bytes each.
The arm64 might have the same problem but it
is currently unable to handle them even in
instruction selection.
Thanks to Jean Dao for reporting the bug.