[wasm] Support block parameters

This adds support for parameters on block, loop, if, cf the multi-value proposal at:
https://github.com/WebAssembly/multi-value/blob/master/proposals/multi-value/Overview.md

With this CL, we ssucceed on all tests in:
https://github.com/WebAssembly/multi-value/pull/2
except those involving multiple returns from functions.

R=titzer@chromium.org

Change-Id: I14a33e86450148f6aed2b8b8cc6bebb2303625c6
Reviewed-on: https://chromium-review.googlesource.com/712578
Commit-Queue: Andreas Rossberg <rossberg@chromium.org>
Reviewed-by: Ben Titzer <titzer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48871}

src/wasm/baseline/liftoff-compiler.cc

@@ -191,7 +191,7 @@ class LiftoffCompiler {
   }
 
   void FallThruTo(Decoder* decoder, Control* c) {
-    if (c->merge.reached) {
+    if (c->end_merge.reached) {
       __ MergeFullStackWith(c->label_state);
     } else {
       c->label_state.Split(*__ cache_state());
@@ -199,7 +199,7 @@ class LiftoffCompiler {
   }
 
   void PopControl(Decoder* decoder, Control* c) {
-    if (!c->is_loop() && c->merge.reached) {
+    if (!c->is_loop() && c->end_merge.reached) {
       __ cache_state()->Steal(c->label_state);
     }
     if (!c->label->is_bound()) {
@@ -383,12 +383,12 @@ class LiftoffCompiler {
     unsupported(decoder, "select");
   }
 
-  void BreakTo(Decoder* decoder, Control* target) {
-    if (!target->merge.reached) {
+  void Br(Decoder* decoder, Control* target) {
+    if (!target->br_merge()->reached) {
       target->label_state.InitMerge(*__ cache_state(), __ num_locals(),
-                                    target->break_arity());
+                                    target->br_merge()->arity);
     }
-    __ MergeStackWith(target->label_state, target->break_arity());
+    __ MergeStackWith(target->label_state, target->br_merge()->arity);
     __ jmp(target->label.get());
   }
 
@@ -397,7 +397,7 @@ class LiftoffCompiler {
     Register value = __ PopToRegister(kWasmI32);
     __ JumpIfZero(value, &cont_false);
 
-    BreakTo(decoder, target);
+    Br(decoder, target);
     __ bind(&cont_false);
   }
 

src/wasm/function-body-decoder.cc

@@ -27,11 +27,6 @@ namespace wasm {
 
 namespace {
 
-template <typename T>
-Vector<T> vec2vec(ZoneVector<T>& vec) {
-  return Vector<T>(vec.data(), vec.size());
-}
-
 // An SsaEnv environment carries the current local variable renaming
 // as well as the current effect and control dependency in the TF graph.
 // It maintains a control state that tracks whether the environment
@@ -173,6 +168,12 @@ class WasmGraphBuildingInterface {
     // The continue environment is the inner environment.
     SetEnv(PrepareForLoop(decoder, finish_try_env));
     ssa_env_->SetNotMerged();
+    if (!decoder->ok()) return;
+    // Wrap input merge into phis.
+    for (unsigned i = 0; i < block->start_merge.arity; ++i) {
+      Value& val = block->start_merge[i];
+      val.node = builder_->Phi(val.type, 1, &val.node, block->end_env->control);
+    }
   }
 
   void Try(Decoder* decoder, Control* block) {
@@ -206,14 +207,11 @@ class WasmGraphBuildingInterface {
 
   void FallThruTo(Decoder* decoder, Control* c) {
     DCHECK(!c->is_loop());
-    MergeValuesInto(decoder, c);
+    MergeValuesInto(decoder, c, &c->end_merge);
   }
 
   void PopControl(Decoder* decoder, Control* block) {
     if (!block->is_loop()) SetEnv(block->end_env);
-    if (block->is_onearmed_if()) {
-      Goto(decoder, block->false_env, block->end_env);
-    }
   }
 
   void EndControl(Decoder* decoder, Control* block) { ssa_env_->Kill(); }
@@ -304,12 +302,8 @@ class WasmGraphBuildingInterface {
     ssa_env_->control = merge;
   }
 
-  void BreakTo(Decoder* decoder, Control* target) {
-    if (target->is_loop()) {
-      Goto(decoder, ssa_env_, target->end_env);
-    } else {
-      MergeValuesInto(decoder, target);
-    }
+  void Br(Decoder* decoder, Control* target) {
+    MergeValuesInto(decoder, target, target->br_merge());
   }
 
   void BrIf(Decoder* decoder, const Value& cond, Control* target) {
@@ -318,7 +312,7 @@ class WasmGraphBuildingInterface {
     fenv->SetNotMerged();
     BUILD(BranchNoHint, cond.node, &tenv->control, &fenv->control);
     ssa_env_ = tenv;
-    BreakTo(decoder, target);
+    Br(decoder, target);
     ssa_env_ = fenv;
   }
 
@@ -327,7 +321,7 @@ class WasmGraphBuildingInterface {
     if (operand.table_count == 0) {
       // Only a default target. Do the equivalent of br.
       uint32_t target = BranchTableIterator<validate>(decoder, operand).next();
-      BreakTo(decoder, decoder->control_at(target));
+      Br(decoder, decoder->control_at(target));
       return;
     }
 
@@ -344,7 +338,7 @@ class WasmGraphBuildingInterface {
       ssa_env_ = Split(decoder, copy);
       ssa_env_->control = (i == operand.table_count) ? BUILD(IfDefault, sw)
                                                      : BUILD(IfValue, i, sw);
-      BreakTo(decoder, decoder->control_at(target));
+      Br(decoder, decoder->control_at(target));
     }
     DCHECK(decoder->ok());
     ssa_env_ = break_env;
@@ -618,7 +612,8 @@ class WasmGraphBuildingInterface {
     }
   }
 
-  void MergeValuesInto(Decoder* decoder, Control* c) {
+  void MergeValuesInto(Decoder* decoder, Control* c, Merge<Value>* merge) {
+    DCHECK(merge == &c->start_merge || merge == &c->end_merge);
     if (!ssa_env_->go()) return;
 
     SsaEnv* target = c->end_env;
@@ -627,10 +622,10 @@ class WasmGraphBuildingInterface {
 
     uint32_t avail =
         decoder->stack_size() - decoder->control_at(0)->stack_depth;
-    uint32_t start = avail >= c->merge.arity ? 0 : c->merge.arity - avail;
-    for (uint32_t i = start; i < c->merge.arity; ++i) {
-      auto& val = decoder->GetMergeValueFromStack(c, i);
-      auto& old = c->merge[i];
+    uint32_t start = avail >= merge->arity ? 0 : merge->arity - avail;
+    for (uint32_t i = start; i < merge->arity; ++i) {
+      auto& val = decoder->GetMergeValueFromStack(c, merge, i);
+      auto& old = (*merge)[i];
       DCHECK_NOT_NULL(val.node);
       DCHECK(val.type == old.type || val.type == kWasmVar);
       old.node = first ? val.node

test/cctest/wasm/test-run-wasm.cc

@@ -120,7 +120,7 @@ WASM_EXEC_TEST(Int32Add_P2) {
 WASM_EXEC_TEST(Int32Add_block1) {
   EXPERIMENTAL_FLAG_SCOPE(mv);
   static const byte code[] = {
-      WASM_BLOCK_TT(0, WASM_GET_LOCAL(0), WASM_GET_LOCAL(1)),
+      WASM_BLOCK_X(0, WASM_GET_LOCAL(0), WASM_GET_LOCAL(1)),
       kExprI32Add};
   RunInt32AddTest(execution_mode, code, sizeof(code));
 }
@@ -128,7 +128,7 @@ WASM_EXEC_TEST(Int32Add_block1) {
 WASM_EXEC_TEST(Int32Add_block2) {
   EXPERIMENTAL_FLAG_SCOPE(mv);
   static const byte code[] = {
-      WASM_BLOCK_TT(0, WASM_GET_LOCAL(0), WASM_GET_LOCAL(1), kExprBr, DEPTH_0),
+      WASM_BLOCK_X(0, WASM_GET_LOCAL(0), WASM_GET_LOCAL(1), kExprBr, DEPTH_0),
       kExprI32Add};
   RunInt32AddTest(execution_mode, code, sizeof(code));
 }
@@ -136,7 +136,7 @@ WASM_EXEC_TEST(Int32Add_block2) {
 WASM_EXEC_TEST(Int32Add_multi_if) {
   EXPERIMENTAL_FLAG_SCOPE(mv);
   static const byte code[] = {
-      WASM_IF_ELSE_TT(0, WASM_GET_LOCAL(0),
+      WASM_IF_ELSE_X(0, WASM_GET_LOCAL(0),
                      WASM_SEQ(WASM_GET_LOCAL(0), WASM_GET_LOCAL(1)),
                      WASM_SEQ(WASM_GET_LOCAL(1), WASM_GET_LOCAL(0))),
       kExprI32Add};

test/common/wasm/wasm-macro-gen.h

@@ -79,7 +79,7 @@
   kExprBlock, static_cast<byte>(WasmOpcodes::ValueTypeCodeFor(t)), \
       __VA_ARGS__, kExprEnd
 
-#define WASM_BLOCK_TT(index, ...)                                  \
+#define WASM_BLOCK_X(index, ...)                                  \
   kExprBlock, static_cast<byte>(index), __VA_ARGS__, kExprEnd
 
 #define WASM_INFINITE_LOOP kExprLoop, kLocalVoid, kExprBr, DEPTH_0, kExprEnd
@@ -94,20 +94,20 @@
   kExprLoop, static_cast<byte>(WasmOpcodes::ValueTypeCodeFor(t)), \
       __VA_ARGS__, kExprEnd
 
-#define WASM_LOOP_TT(index, ...)                                  \
+#define WASM_LOOP_X(index, ...)                                   \
   kExprLoop, static_cast<byte>(index), __VA_ARGS__, kExprEnd
 
-#define WASM_IF(cond, tstmt) cond, kExprIf, kLocalVoid, tstmt, kExprEnd
+#define WASM_IF(cond, ...) cond, kExprIf, kLocalVoid, __VA_ARGS__, kExprEnd
 
-#define WASM_IF_ELSE(cond, tstmt, fstmt) \
-  cond, kExprIf, kLocalVoid, tstmt, kExprElse, fstmt, kExprEnd
+#define WASM_IF_T(t, cond, ...)                                       \
+  cond, kExprIf, static_cast<byte>(WasmOpcodes::ValueTypeCodeFor(t)), \
+      __VA_ARGS__, kExprEnd
 
-#define WASM_IF_ELSE_T(t, cond, tstmt, fstmt)                                \
-  cond, kExprIf, static_cast<byte>(WasmOpcodes::ValueTypeCodeFor(t)), tstmt, \
-      kExprElse, fstmt, kExprEnd
+#define WASM_IF_X(index, cond, ...)                                   \
+  cond, kExprIf, static_cast<byte>(index), __VA_ARGS__, kExprEnd
 
-#define WASM_IF_ELSE_TT(index, cond, tstmt, fstmt)                           \
-  cond, kExprIf, static_cast<byte>(index), tstmt, kExprElse, fstmt, kExprEnd
+#define WASM_IF_ELSE(cond, tstmt, fstmt) \
+  cond, kExprIf, kLocalVoid, tstmt, kExprElse, fstmt, kExprEnd
 
 #define WASM_IF_ELSE_I(cond, tstmt, fstmt) \
   cond, kExprIf, kLocalI32, tstmt, kExprElse, fstmt, kExprEnd
@@ -118,6 +118,13 @@
 #define WASM_IF_ELSE_D(cond, tstmt, fstmt) \
   cond, kExprIf, kLocalF64, tstmt, kExprElse, fstmt, kExprEnd
 
+#define WASM_IF_ELSE_T(t, cond, tstmt, fstmt)                                \
+  cond, kExprIf, static_cast<byte>(WasmOpcodes::ValueTypeCodeFor(t)), tstmt, \
+      kExprElse, fstmt, kExprEnd
+
+#define WASM_IF_ELSE_X(index, cond, tstmt, fstmt)                            \
+  cond, kExprIf, static_cast<byte>(index), tstmt, kExprElse, fstmt, kExprEnd
+
 #define WASM_SELECT(tval, fval, cond) tval, fval, cond, kExprSelect
 
 #define WASM_RETURN0 kExprReturn
@@ -574,7 +581,7 @@ inline WasmOpcode LoadStoreOpcodeOf(MachineType type, bool store) {
 #define SIZEOF_SIG_ENTRY_x_xx 6
 #define SIZEOF_SIG_ENTRY_x_xxx 7
 
-#define WASM_BRV(depth, val) val, kExprBr, static_cast<byte>(depth)
+#define WASM_BRV(depth, ...) __VA_ARGS__, kExprBr, static_cast<byte>(depth)
 #define WASM_BRV_IF(depth, val, cond) \
   val, cond, kExprBrIf, static_cast<byte>(depth)
 #define WASM_BRV_IFD(depth, val, cond) \

test/mjsunit/wasm/multi-value.js

+// Copyright 2017 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: --experimental-wasm-mv
+
+load("test/mjsunit/wasm/wasm-constants.js");
+load("test/mjsunit/wasm/wasm-module-builder.js");
+
+(function MultiBlockResultTest() {
+  print("MultiBlockResultTest");
+  let builder = new WasmModuleBuilder();
+  let sig_i_ii = builder.addType(kSig_i_ii);
+  let sig_ii_v = builder.addType(kSig_ii_v);
+
+  builder.addFunction("main", kSig_i_ii)
+    .addBody([
+      kExprBlock, sig_ii_v,
+      kExprGetLocal, 0,
+      kExprGetLocal, 1,
+      kExprEnd,
+      kExprI32Add])
+    .exportAs("main");
+
+  let module = new WebAssembly.Module(builder.toBuffer());
+  let instance = new WebAssembly.Instance(module);
+  assertEquals(instance.exports.main(1, 4), 5);
+})();
+
+(function MultiBlockParamTest() {
+  print("MultiBlockParamTest");
+  let builder = new WasmModuleBuilder();
+  let sig_i_ii = builder.addType(kSig_i_ii);
+
+  builder.addFunction("main", kSig_i_ii)
+    .addBody([
+      kExprGetLocal, 0,
+      kExprGetLocal, 1,
+      kExprBlock, sig_i_ii,
+      kExprI32Add,
+      kExprEnd])
+    .exportAs("main");
+
+  let module = new WebAssembly.Module(builder.toBuffer());
+  let instance = new WebAssembly.Instance(module);
+  assertEquals(instance.exports.main(1, 4), 5);
+})();
+
+(function MultiBlockBrTest() {
+  print("MultiBlockBrTest");
+  let builder = new WasmModuleBuilder();
+  let sig_i_ii = builder.addType(kSig_i_ii);
+  let sig_ii_v = builder.addType(kSig_ii_v);
+
+  builder.addFunction("main", kSig_i_ii)
+    .addBody([
+      kExprBlock, sig_ii_v,
+      kExprGetLocal, 0,
+      kExprGetLocal, 1,
+      kExprBr, 0,
+      kExprEnd,
+      kExprI32Add])
+    .exportAs("main");
+
+  let module = new WebAssembly.Module(builder.toBuffer());
+  let instance = new WebAssembly.Instance(module);
+  assertEquals(instance.exports.main(1, 4), 5);
+})();
+
+
+(function MultiLoopResultTest() {
+  print("MultiLoopResultTest");
+  let builder = new WasmModuleBuilder();
+  let sig_i_ii = builder.addType(kSig_i_ii);
+  let sig_ii_v = builder.addType(kSig_ii_v);
+
+  builder.addFunction("main", kSig_i_ii)
+    .addBody([
+      kExprLoop, sig_ii_v,
+      kExprGetLocal, 0,
+      kExprGetLocal, 1,
+      kExprEnd,
+      kExprI32Add])
+    .exportAs("main");
+
+  let module = new WebAssembly.Module(builder.toBuffer());
+  let instance = new WebAssembly.Instance(module);
+  assertEquals(instance.exports.main(1, 4), 5);
+})();
+
+(function MultiLoopParamTest() {
+  print("MultiLoopParamTest");
+  let builder = new WasmModuleBuilder();
+  let sig_i_ii = builder.addType(kSig_i_ii);
+
+  builder.addFunction("main", kSig_i_ii)
+    .addBody([
+      kExprGetLocal, 0,
+      kExprGetLocal, 1,
+      kExprLoop, sig_i_ii,
+      kExprI32Add,
+      kExprEnd])
+    .exportAs("main");
+
+  let module = new WebAssembly.Module(builder.toBuffer());
+  let instance = new WebAssembly.Instance(module);
+  assertEquals(instance.exports.main(1, 4), 5);
+})();
+
+(function MultiLoopBrTest() {
+  print("MultiLoopBrTest");
+  let builder = new WasmModuleBuilder();
+  let sig_i_ii = builder.addType(kSig_i_ii);
+  let sig_ii_i = builder.addType(kSig_ii_i);
+  let sig_ii_ii = builder.addType(kSig_ii_ii);
+
+  builder.addFunction("dup", kSig_ii_i)
+    .addBody([kExprGetLocal, 0, kExprGetLocal, 0]);
+  builder.addFunction("swap", kSig_ii_ii)
+    .addBody([kExprGetLocal, 1, kExprGetLocal, 0]);
+  builder.addFunction("main", kSig_i_ii)
+    .addBody([
+      kExprGetLocal, 0,
+      kExprGetLocal, 1,
+      kExprLoop, sig_ii_ii,
+      kExprCallFunction, 1,  // swap
+      kExprCallFunction, 0,  // dup
+      kExprI32Add,
+      kExprCallFunction, 0,  // dup
+      kExprI32Const, 20,
+      kExprI32LeU,
+      kExprBrIf, 0,
+      kExprEnd,
+      kExprDrop])
+    .exportAs("main");
+
+  let module = new WebAssembly.Module(builder.toBuffer());
+  let instance = new WebAssembly.Instance(module);
+  assertEquals(0, instance.exports.main(0, 1));
+  assertEquals(16, instance.exports.main(1, 1));
+  assertEquals(4, instance.exports.main(3, 1));
+  assertEquals(4, instance.exports.main(4, 1));
+  assertEquals(0, instance.exports.main(0, 2));
+  assertEquals(16, instance.exports.main(1, 2));
+  assertEquals(8, instance.exports.main(3, 2));
+  assertEquals(8, instance.exports.main(4, 2));
+  assertEquals(0, instance.exports.main(0, 3));
+  assertEquals(8, instance.exports.main(1, 3));
+  assertEquals(12, instance.exports.main(3, 3));
+  assertEquals(12, instance.exports.main(4, 3));
+  assertEquals(0, instance.exports.main(0, 4));
+  assertEquals(8, instance.exports.main(1, 4));
+  assertEquals(16, instance.exports.main(3, 4));
+  assertEquals(16, instance.exports.main(4, 4));
+  assertEquals(3, instance.exports.main(100, 3));
+  assertEquals(6, instance.exports.main(3, 100));
+})();
+
+
+(function MultiIfResultTest() {
+  print("MultiIfResultTest");
+  let builder = new WasmModuleBuilder();
+  let sig_i_ii = builder.addType(kSig_i_ii);
+  let sig_ii_v = builder.addType(kSig_ii_v);
+
+  builder.addFunction("main", kSig_i_ii)
+    .addBody([
+      kExprGetLocal, 0,
+      kExprIf, sig_ii_v,
+      kExprGetLocal, 0,
+      kExprGetLocal, 1,
+      kExprElse,
+      kExprGetLocal, 1,
+      kExprGetLocal, 0,
+      kExprEnd,
+      kExprI32Sub])
+    .exportAs("main");
+
+  let module = new WebAssembly.Module(builder.toBuffer());
+  let instance = new WebAssembly.Instance(module);
+  assertEquals(instance.exports.main(8, 3), 5);
+  assertEquals(instance.exports.main(0, 3), 3);
+})();
+
+(function MultiIfParamTest() {
+  print("MultiIfParamTest");
+  let builder = new WasmModuleBuilder();
+  let sig_i_ii = builder.addType(kSig_i_ii);
+
+  builder.addFunction("main", kSig_i_ii)
+    .addBody([
+      kExprGetLocal, 0,
+      kExprGetLocal, 1,
+      kExprGetLocal, 0,
+      kExprIf, sig_i_ii,
+      kExprI32Add,
+      kExprElse,
+      kExprI32Sub,
+      kExprEnd])
+    .exportAs("main");
+
+  let module = new WebAssembly.Module(builder.toBuffer());
+  let instance = new WebAssembly.Instance(module);
+  assertEquals(instance.exports.main(1, 4), 5);
+  assertEquals(instance.exports.main(0, 4), -4);
+})();
+
+(function MultiIfBrTest() {
+  print("MultiIfBrTest");
+  let builder = new WasmModuleBuilder();
+  let sig_i_ii = builder.addType(kSig_i_ii);
+  let sig_ii_v = builder.addType(kSig_ii_v);
+
+  builder.addFunction("main", kSig_i_ii)
+    .addBody([
+      kExprGetLocal, 0,
+      kExprIf, sig_ii_v,
+      kExprGetLocal, 0,
+      kExprGetLocal, 1,
+      kExprBr, 0,
+      kExprElse,
+      kExprGetLocal, 1,
+      kExprGetLocal, 0,
+      kExprBr, 0,
+      kExprEnd,
+      kExprI32Sub])
+    .exportAs("main");
+
+  let module = new WebAssembly.Module(builder.toBuffer());
+  let instance = new WebAssembly.Instance(module);
+  assertEquals(instance.exports.main(8, 3), 5);
+  assertEquals(instance.exports.main(0, 3), 3);
+})();

test/mjsunit/wasm/wasm-constants.js

@@ -123,6 +123,10 @@ let kSig_v_l = makeSig([kWasmI64], []);
 let kSig_v_d = makeSig([kWasmF64], []);
 let kSig_v_dd = makeSig([kWasmF64, kWasmF64], []);
 let kSig_v_ddi = makeSig([kWasmF64, kWasmF64, kWasmI32], []);
+let kSig_ii_v = makeSig([], [kWasmI32, kWasmI32]);
+let kSig_iii_v = makeSig([], [kWasmI32, kWasmI32, kWasmI32]);
+let kSig_ii_i = makeSig([kWasmI32], [kWasmI32, kWasmI32]);
+let kSig_ii_ii = makeSig([kWasmI32, kWasmI32], [kWasmI32, kWasmI32]);
 
 let kSig_v_f = makeSig([kWasmF32], []);
 let kSig_f_f = makeSig([kWasmF32], [kWasmF32]);