Previously, an "r" constraint would mean the compiler provides a value
on WebAssembly's operand stack. This was tricky to use properly,
particularly since it isn't possible to declare a new local from within
an inline asm string.
With this patch, "r" provides the value in a WebAssembly local, and the
local index is provided to the inline asm string. This requires inline
asm to use get_local and set_local to read the register. This does
potentially result in larger code size, however inline asm should
hopefully be quite rare in WebAssembly.
This also means that the "m" constraint can no longer be supported, as
WebAssembly has nothing like a "memory operand" that includes an
implicit get_local.
This fixes PR34599 for the wasm32-unknown-unknown-wasm target (though
not for the ELF target).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@317707 91177308-0d34-0410-b5e6-96231b3b80d8
To facilitate this, add a new hidden command-line option to disable
the explicit-locals pass. That causes llc to emit invalid code that doesn't
have all locals converted to get_local/set_local, however it simplifies
testwriting in many cases.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@296540 91177308-0d34-0410-b5e6-96231b3b80d8
Add -no-integrated-as to this test, since it's testing inline asm strings
that aren't actually valid assembly syntax.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@257519 91177308-0d34-0410-b5e6-96231b3b80d8
These tests aren't testing that the result is valid syntax; they're testing
that the compiler emits the inline asm operands correctly.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253469 91177308-0d34-0410-b5e6-96231b3b80d8
This also takes the push/pop syntax another step forward, introducing stack
slot numbers to make it easier to see how expressions are connected. For
example, the value pushed in $push7 is popped in $pop7.
And, this begins an experiment with making get_local and set_local implicit
when an operation directly uses or defines a register. This greatly reduces
clutter. If this experiment succeeds, it may make sense to do this for
const instructions as well.
And, this introduces more special code for ARGUMENTS; hopefully this code
will soon be obviated by proper support for live-in virtual registers.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253465 91177308-0d34-0410-b5e6-96231b3b80d8
