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Sam Clegg e7c9a10ed2 [WebAssembly] Fix code generated for atomic operations in PIC mode
The main this this test does is to add the `IsNotPIC` predicate to the
all the atomic instructions pattern that directly refer to
`tglobaladdr`.

This is because in PIC mode we need to generate separate instruction
sequence (either a direct global.get, or __memory_base + offset) for
accessing global addresses.

As part of this change I noticed that many of the `Requires` attributes
added to the instruction in `WebAssemblyInstrAtomics.td` were being
honored.  This is because the wrapped in a `let Predicates =
[HasAtomics]` block and it seems that that outer wrapping overrides any
`Requires` on defs within it.   As a workaround I removed the outer
`let` and added `HasAtomics` to all the inner `Requires`.  I believe
that all the instrucitons that don't have `Requires` explicit bottom out
in `ATOMIC_I` and `ATOMIC_NRI` which have `HasAtomics` so this should
not remove this predicate from any patterns (at least that is the idea).

The alternative to this approach looks like implementing something
like `PredicateControl` in `Mips.td` where we can split the predicates
into groups so they don't clobber each other.

Differential Revision: https://reviews.llvm.org/D92744
2020-12-08 18:41:32 -08:00

35 lines
1.6 KiB
LLVM

; RUN: llc < %s -asm-verbose=false -relocation-model=pic -fast-isel -wasm-disable-explicit-locals -wasm-keep-registers -mattr=+atomics,+sign-ext | FileCheck %s
; RUN: llc < %s -asm-verbose=false -relocation-model=pic -fast-isel=false -wasm-disable-explicit-locals -wasm-keep-registers -mattr=+atomics,+sign-ext | FileCheck %s
; Test that atomic operations in PIC mode. Specifically we verify
; that atomic operations on global address load addres via @GOT or
; @MBREL relocations.
target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
target triple = "wasm32-unknown-emscripten"
@external_global = external global i32
@hidden_global = external hidden global i32
define i32 @rmw_add_external_global() {
; CHECK-LABEL: rmw_add_external_global:
; CHECK: global.get $push[[L0:[0-9]+]]=, external_global@GOT{{$}}
; CHECK-NEXT: i32.const $push[[L1:[0-9]+]]=, 42{{$}}
; CHECK-NEXT: i32.atomic.rmw.add $push[[L2:[0-9]+]]=, 0($pop[[L0]]), $pop[[L1]]{{$}}
; CHECK-NEXT: end_function
%1 = atomicrmw add i32* @external_global, i32 42 seq_cst
ret i32 %1
}
define i32 @rmw_add_hidden_global() {
; CHECK-LABEL: rmw_add_hidden_global:
; CHECK: global.get $push[[L0:[0-9]+]]=, __memory_base{{$}}
; CHECK-NEXT: i32.const $push[[L1:[0-9]+]]=, hidden_global@MBREL{{$}}
; CHECK-NEXT: i32.add $push[[L2:[0-9]+]]=, $pop[[L0]], $pop[[L1]]{{$}}
; CHECK-NEXT: i32.const $push[[L3:[0-9]+]]=, 42{{$}}
; CHECK-NEXT: i32.atomic.rmw.add $push[[L4:[0-9]+]]=, 0($pop[[L2]]), $pop[[L3]]{{$}}
; CHECK-NEXT: end_function
%1 = atomicrmw add i32* @hidden_global, i32 42 seq_cst
ret i32 %1
}