Hood ChathamandPaulo Matos
765f0d14fe
Originally #71540 by Paolo Matos, I picked it up and finished it. Resolves https://github.com/llvm/llvm-project/issues/69894. Model WebAssembly externref and funcref as target("wasm.externref") / target("wasm.funcref") TargetExtTypes instead of pointers in non-integral address spaces 10 and 20. The entire WebAssemblyLowerRefTypesIntPtrConv can be removed. This breaks the GlobalISel handling for reference types, I just disabled GlobalISel handling for functions that use them. I added intrinsics for `wasm.ptr.to_funcref` and `wasm.funcref.to_ptr`. ptr.to_funcref does a table.get from the indirect function pointer table. As a special case, 0 is converted to the null funcref rather than doing table.get on 0. `wasm.funcref.to_ptr` is only handled when we call it immediately, otherwise it will fail to lower. We could dynamically put the funcref into the table to make it work but that would require a stack of spilled funcrefs and isn't worth the effort. In the process of looking into this, I noticed that clang used to allow casting from funcref to function pointer but if the cast result escaped it would hit `Cannot select: FUNCREF_TO_PTR` in the backend. I added a diagnostic that says "a funcref can only be converted to a pointer to be directly called" to make this a little cleaner. cc @QuantumSegfault --------- Co-authored-by: Paulo Matos <pmatos@igalia.com>
29 lines
1.1 KiB
LLVM
29 lines
1.1 KiB
LLVM
; RUN: llc < %s --mtriple=wasm32-unknown-unknown -asm-verbose=false -mattr=+reference-types | FileCheck %s
|
|
; RUN: llc < %s --mtriple=wasm64-unknown-unknown -asm-verbose=false -mattr=+reference-types | FileCheck %s --check-prefix=CHECK64
|
|
|
|
%funcref = type target("wasm.funcref")
|
|
|
|
declare %funcref @llvm.wasm.ptr.to_funcref(ptr) nounwind
|
|
|
|
; CHECK: .tabletype __indirect_function_table, funcref
|
|
|
|
; Converting a function pointer to a funcref is a table.get from the
|
|
; __indirect_function_table.
|
|
define %funcref @ptr_to_funcref(ptr %p) {
|
|
; CHECK-LABEL: ptr_to_funcref:
|
|
; CHECK: .functype ptr_to_funcref (i32) -> (funcref)
|
|
; CHECK-NEXT: local.get 0
|
|
; CHECK-NEXT: table.get __indirect_function_table
|
|
; CHECK-NEXT: end_function
|
|
;
|
|
; On wasm64 the function pointer is an i64 and must be wrapped to i32 first.
|
|
; CHECK64-LABEL: ptr_to_funcref:
|
|
; CHECK64: .functype ptr_to_funcref (i64) -> (funcref)
|
|
; CHECK64-NEXT: local.get 0
|
|
; CHECK64-NEXT: i32.wrap_i64
|
|
; CHECK64-NEXT: table.get __indirect_function_table
|
|
; CHECK64-NEXT: end_function
|
|
%ref = call %funcref @llvm.wasm.ptr.to_funcref(ptr %p)
|
|
ret %funcref %ref
|
|
}
|