From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Thibaud Michaud <thibaudm@chromium.org>
Date: Thu, 15 Oct 2020 12:45:34 +0200
Subject: Merged: [codegen] Skip invalid optimization in tail calls
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Preparing for tail call is usually done by emitting the gap moves and
then moving the stack pointer to its new position. An optimization
consists in moving the stack pointer first and transforming some of the
moves into pushes. In the attached case it looks like this (arm):

138  add sp, sp, #40
13c  str r6, [sp, #-4]!
140  str r6, [sp, #-4]!
144  str r6, [sp, #-4]!
148  str r6, [sp, #-4]!
14c  str r6, [sp, #-4]!
...
160  vldr d1, [sp - 4*3]

The last line is a gap reload, but because the stack pointer was already
moved, the slot is now below the stack pointer. This is invalid and
triggers this DCHECK:

Fatal error in ../../v8/src/codegen/arm/assembler-arm.cc, line 402
Debug check failed: 0 <= offset (0 vs. -12).

A comment already explains that we skip the optimization if the gap
contains stack moves to prevent this, but the code only checks for
non-FP slots. This is fixed by replacing "source.IsStackSlot()" with
"source.IsAnyStackSlot()":

108  vldr d1, [sp + 4*2]
...
118  str r0, [sp, #+36]
11c  str r0, [sp, #+32]
120  str r0, [sp, #+28]
124  str r0, [sp, #+24]
128  str r0, [sp, #+20]
...
134  add sp, sp, #20

TBR=​jgruber@chromium.org

(cherry picked from commit 7506e063d0d7fb00e4b9c06735c91e1953296867)

Change-Id: I66ed6187755af956e245207e940c83ea0697a5e6
Bug: chromium:1137608
No-Try: true
No-Presubmit: true
No-Tree-Checks: true
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2505976
Reviewed-by: Thibaud Michaud <thibaudm@chromium.org>
Commit-Queue: Thibaud Michaud <thibaudm@chromium.org>
Cr-Commit-Position: refs/branch-heads/8.6@{#42}
Cr-Branched-From: a64aed2333abf49e494d2a5ce24bbd14fff19f60-refs/heads/8.6.395@{#1}
Cr-Branched-From: a626bc036236c9bf92ac7b87dc40c9e538b087e3-refs/heads/master@{#69472}

diff --git a/src/compiler/backend/code-generator.cc b/src/compiler/backend/code-generator.cc
index 9dbd5fac333c557f8e7de9b63d18b68f94b817e7..0a2e37c5e67d6d2d512bb970ec38d9a25c2560c9 100644
--- a/src/compiler/backend/code-generator.cc
+++ b/src/compiler/backend/code-generator.cc
@@ -607,8 +607,8 @@ void CodeGenerator::GetPushCompatibleMoves(Instruction* instr,
         // then the full gap resolver must be used since optimization with
         // pushes don't participate in the parallel move and might clobber
         // values needed for the gap resolve.
-        if (source.IsStackSlot() && LocationOperand::cast(source).index() >=
-                                        first_push_compatible_index) {
+        if (source.IsAnyStackSlot() && LocationOperand::cast(source).index() >=
+                                           first_push_compatible_index) {
           pushes->clear();
           return;
         }
diff --git a/test/mjsunit/regress/wasm/regress-1137608.js b/test/mjsunit/regress/wasm/regress-1137608.js
new file mode 100644
index 0000000000000000000000000000000000000000..5011dced2f70ffbe2b6096a4e1863f434c8898a8
--- /dev/null
+++ b/test/mjsunit/regress/wasm/regress-1137608.js
@@ -0,0 +1,46 @@
+// 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.
+//
+// Flags: --no-liftoff --experimental-wasm-return-call --experimental-wasm-threads
+
+load("test/mjsunit/wasm/wasm-module-builder.js");
+
+(function Regress1137608() {
+  print(arguments.callee.name);
+  let builder = new WasmModuleBuilder();
+  let sig0 = builder.addType(kSig_i_iii);
+  let sig1 = builder.addType(makeSig([kWasmF64, kWasmF64, kWasmI32,
+        kWasmI32, kWasmI32, kWasmF32, kWasmI32, kWasmF64, kWasmI32, kWasmF32,
+        kWasmI32, kWasmF32, kWasmI32, kWasmF64, kWasmI32], [kWasmI32]));
+  let main = builder.addFunction("main", sig0)
+      .addBody([
+        kExprI64Const, 0,
+        kExprF64UConvertI64,
+        kExprF64Const, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x00, 0x00,
+        kExprF64Const, 0x30, 0x30, 0x30, 0x00, 0x00, 0x00, 0x00, 0x00,
+        kExprF64Mul,
+        kExprI32Const, 0,
+        kExprF64Const, 0x30, 0x30, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        kExprF64StoreMem, 0x00, 0xb0, 0xe0, 0xc0, 0x81, 0x03,
+        kExprI32Const, 0,
+        kExprI32Const, 0,
+        kExprI32Const, 0,
+        kExprF32Const, 0x00, 0x00, 0x00, 0x00,
+        kExprI32Const, 0,
+        kExprF64Const, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        kExprI32Const, 0,
+        kExprF32Const, 0x00, 0x00, 0x00, 0x00,
+        kExprI32Const, 0,
+        kExprF32Const, 0x00, 0x00, 0x00, 0x00,
+        kExprI32Const, 0,
+        kExprF64Const, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        kExprI32Const, 0,
+        kExprI32Const, 2,
+        kExprReturnCallIndirect, sig1, kTableZero]).exportFunc();
+  builder.addFunction("f", sig1).addBody([kExprI32Const, 0]);
+  builder.addTable(kWasmAnyFunc, 4, 4);
+  builder.addMemory(16, 32, false, true);
+  let module = new WebAssembly.Module(builder.toBuffer());
+  let instance = new WebAssembly.Instance(module);
+})();
