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deps: V8: cherry-pick eddb82330975
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Original commit message:

    Merged: [wasm][liftoff] Fix register usage for i64_addi

    The arm implementation made the assumption that the {lhs} and {dst}
    registers are either the same, or there is no overlap. This assumption
    does not hold.
    ia32 on the other hand has a lot of complicated logic (and unnecessary
    code generation) for different cases of overlap.

    This CL fixes the arm issue *and* simplifies the ia32 logic by making
    the arm assumption hold, and using it to eliminate special handling on
    ia32.

    R=​thibaudm@chromium.org

    (cherry picked from commit 89ca48c907e25ef94a135255092c4e150654c4fc)

    Bug: chromium:1146861
    Change-Id: I96c4985fb8ff710b98e009e457444fc8804bce58
    No-Try: true
    No-Presubmit: true
    No-Tree-Checks: true
    Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2584242
    Reviewed-by: Thibaud Michaud <thibaudm@chromium.org>
    Commit-Queue: Clemens Backes <clemensb@chromium.org>
    Cr-Commit-Position: refs/branch-heads/8.6@{#50}
    Cr-Branched-From: a64aed2333abf49e494d2a5ce24bbd14fff19f60-refs/heads/8.6.395@{#1}
    Cr-Branched-From: a626bc036236c9bf92ac7b87dc40c9e538b087e3-refs/heads/master@{#69472}

Refs: v8/v8@eddb823

PR-URL: #38275
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Jiawen Geng <technicalcute@gmail.com>
Reviewed-By: Shelley Vohr <codebytere@gmail.com>
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targos committed Apr 30, 2021
1 parent 4d0bc38 commit 42140a1
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Showing 5 changed files with 73 additions and 24 deletions.
2 changes: 1 addition & 1 deletion common.gypi
Expand Up @@ -36,7 +36,7 @@

# Reset this number to 0 on major V8 upgrades.
# Increment by one for each non-official patch applied to deps/v8.
'v8_embedder_string': '-node.56',
'v8_embedder_string': '-node.57',

##### V8 defaults for Node.js #####

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2 changes: 2 additions & 0 deletions deps/v8/src/wasm/baseline/arm/liftoff-assembler-arm.h
Expand Up @@ -140,6 +140,8 @@ template <void (Assembler::*op)(Register, Register, const Operand&, SBit,
SBit, Condition)>
inline void I64BinopI(LiftoffAssembler* assm, LiftoffRegister dst,
LiftoffRegister lhs, int32_t imm) {
// The compiler allocated registers such that either {dst == lhs} or there is
// no overlap between the two.
DCHECK_NE(dst.low_gp(), lhs.high_gp());
(assm->*op)(dst.low_gp(), lhs.low_gp(), Operand(imm), SetCC, al);
// Top half of the immediate sign extended, either 0 or -1.
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30 changes: 9 additions & 21 deletions deps/v8/src/wasm/baseline/ia32/liftoff-assembler-ia32.h
Expand Up @@ -1097,31 +1097,19 @@ template <void (Assembler::*op)(Register, const Immediate&),
void (Assembler::*op_with_carry)(Register, int32_t)>
inline void OpWithCarryI(LiftoffAssembler* assm, LiftoffRegister dst,
LiftoffRegister lhs, int32_t imm) {
// First, compute the low half of the result, potentially into a temporary dst
// register if {dst.low_gp()} equals any register we need to
// keep alive for computing the upper half.
LiftoffRegList keep_alive = LiftoffRegList::ForRegs(lhs.high_gp());
Register dst_low = keep_alive.has(dst.low_gp())
? assm->GetUnusedRegister(kGpReg, keep_alive).gp()
: dst.low_gp();

if (dst_low != lhs.low_gp()) assm->mov(dst_low, lhs.low_gp());
(assm->*op)(dst_low, Immediate(imm));
// The compiler allocated registers such that either {dst == lhs} or there is
// no overlap between the two.
DCHECK_NE(dst.low_gp(), lhs.high_gp());

// Now compute the upper half, while keeping alive the previous result.
keep_alive = LiftoffRegList::ForRegs(dst_low);
Register dst_high = keep_alive.has(dst.high_gp())
? assm->GetUnusedRegister(kGpReg, keep_alive).gp()
: dst.high_gp();
// First, compute the low half of the result.
if (dst.low_gp() != lhs.low_gp()) assm->mov(dst.low_gp(), lhs.low_gp());
(assm->*op)(dst.low_gp(), Immediate(imm));

if (dst_high != lhs.high_gp()) assm->mov(dst_high, lhs.high_gp());
// Now compute the upper half.
if (dst.high_gp() != lhs.high_gp()) assm->mov(dst.high_gp(), lhs.high_gp());
// Top half of the immediate sign extended, either 0 or -1.
int32_t sign_extend = imm < 0 ? -1 : 0;
(assm->*op_with_carry)(dst_high, sign_extend);

// If necessary, move result into the right registers.
LiftoffRegister tmp_result = LiftoffRegister::ForPair(dst_low, dst_high);
if (tmp_result != dst) assm->Move(dst, tmp_result, kWasmI64);
(assm->*op_with_carry)(dst.high_gp(), sign_extend);
}
} // namespace liftoff

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7 changes: 5 additions & 2 deletions deps/v8/src/wasm/baseline/liftoff-compiler.cc
Expand Up @@ -1122,9 +1122,12 @@ class LiftoffCompiler {
int32_t imm = rhs_slot.i32_const();

LiftoffRegister lhs = __ PopToRegister();
// Either reuse {lhs} for {dst}, or choose a register (pair) which does
// not overlap, for easier code generation.
LiftoffRegList pinned = LiftoffRegList::ForRegs(lhs);
LiftoffRegister dst = src_rc == result_rc
? __ GetUnusedRegister(result_rc, {lhs}, {})
: __ GetUnusedRegister(result_rc, {});
? __ GetUnusedRegister(result_rc, {lhs}, pinned)
: __ GetUnusedRegister(result_rc, pinned);

CallEmitFn(fnImm, dst, lhs, imm);
__ PushRegister(ValueType(result_type), dst);
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56 changes: 56 additions & 0 deletions deps/v8/test/mjsunit/regress/wasm/regress-1146861.js
@@ -0,0 +1,56 @@
// Copyright 2020 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

load('test/mjsunit/wasm/wasm-module-builder.js');

const builder = new WasmModuleBuilder();
builder.addGlobal(kWasmI32, 1);
builder.addType(makeSig([], [kWasmF64]));
// Generate function 1 (out of 1).
builder.addFunction(undefined, 0 /* sig */)
.addLocals(kWasmI32, 8).addLocals(kWasmI64, 3)
.addBodyWithEnd([
// signature: d_v
// body:
kExprGlobalGet, 0x00, // global.get
kExprLocalSet, 0x00, // local.set
kExprI32Const, 0x00, // i32.const
kExprI32Eqz, // i32.eqz
kExprLocalSet, 0x01, // local.set
kExprGlobalGet, 0x00, // global.get
kExprLocalSet, 0x02, // local.set
kExprI32Const, 0x01, // i32.const
kExprI32Const, 0x01, // i32.const
kExprI32Sub, // i32.sub
kExprLocalSet, 0x03, // local.set
kExprGlobalGet, 0x00, // global.get
kExprLocalSet, 0x04, // local.set
kExprI32Const, 0x00, // i32.const
kExprI32Eqz, // i32.eqz
kExprLocalSet, 0x05, // local.set
kExprGlobalGet, 0x00, // global.get
kExprLocalSet, 0x06, // local.set
kExprI32Const, 0x00, // i32.const
kExprI32Const, 0x01, // i32.const
kExprI32Sub, // i32.sub
kExprLocalSet, 0x07, // local.set
kExprBlock, kWasmStmt, // block @45
kExprI32Const, 0x00, // i32.const
kExprIf, kWasmStmt, // if @49
kExprLocalGet, 0x0a, // local.get
kExprLocalSet, 0x08, // local.set
kExprElse, // else @55
kExprNop, // nop
kExprEnd, // end @57
kExprLocalGet, 0x08, // local.get
kExprLocalSet, 0x09, // local.set
kExprLocalGet, 0x09, // local.get
kExprI64Const, 0xff, 0x01, // i64.const
kExprI64Add, // i64.add
kExprDrop, // drop
kExprEnd, // end @69
kExprF64Const, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xf0, 0x3f, // f64.const
kExprEnd, // end @79
]);
builder.instantiate();

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