From 62a720f33e06ea0151c48c5232c1671695600b56 Mon Sep 17 00:00:00 2001
From: ctw-ian <chentingwei2@huawei.com>
Date: Fri, 28 Oct 2022 03:02:57 +0000
Subject: [PATCH] Support Nullish Coalesce for es2abc

Issue:I5Y710

Signed-off-by: ctw-ian <chentingwei2@huawei.com>
Change-Id: Id4f644ea75dacab914942164a6b4711b82339605
---
 es2panda/compiler/core/pandagen.cpp           | 10 ++++++++++
 es2panda/compiler/core/pandagen.h             |  1 +
 es2panda/ir/expressions/binaryExpression.cpp  | 20 +++++++++++--------
 .../nullishCoalesce-expected.txt              |  5 +++++
 .../js/binaryExpression/nullishCoalesce.js    |  9 +++++++++
 5 files changed, 37 insertions(+), 8 deletions(-)
 create mode 100644 es2panda/test/compiler/js/binaryExpression/nullishCoalesce-expected.txt
 create mode 100644 es2panda/test/compiler/js/binaryExpression/nullishCoalesce.js

diff --git a/es2panda/compiler/core/pandagen.cpp b/es2panda/compiler/core/pandagen.cpp
index cb818ac68f..8f73b7758a 100644
--- a/es2panda/compiler/core/pandagen.cpp
+++ b/es2panda/compiler/core/pandagen.cpp
@@ -961,6 +961,16 @@ void PandaGen::BranchIfFalse(const ir::AstNode *node, Label *target)
     sa_.Emit<Jnez>(node, target);
 }
 
+void PandaGen::BranchIfStrictNull(const ir::AstNode *node, class Label *target)
+{
+    RegScope rs(this);
+    VReg tmp = AllocReg();
+    StoreAccumulator(node, tmp);
+    LoadConst(node, Constant::JS_NULL);
+    ra_.Emit<EcmaStricteqdyn>(node, tmp);
+    sa_.Emit<Jnez>(node, target);
+}
+
 void PandaGen::EmitThrow(const ir::AstNode *node)
 {
     sa_.Emit<EcmaThrowdyn>(node);
diff --git a/es2panda/compiler/core/pandagen.h b/es2panda/compiler/core/pandagen.h
index 445d4abb0d..640c497ba9 100644
--- a/es2panda/compiler/core/pandagen.h
+++ b/es2panda/compiler/core/pandagen.h
@@ -281,6 +281,7 @@ public:
     void BranchIfNotTrue(const ir::AstNode *node, class Label *target);
     void BranchIfFalse(const ir::AstNode *node, class Label *target);
     void BranchIfNotFalse(const ir::AstNode *node, class Label *target);
+    void BranchIfStrictNull(const ir::AstNode *node, class Label *target);
 
     void EmitThrow(const ir::AstNode *node);
     void EmitRethrow(const ir::AstNode *node);
diff --git a/es2panda/ir/expressions/binaryExpression.cpp b/es2panda/ir/expressions/binaryExpression.cpp
index b34d315374..c00c7d434d 100644
--- a/es2panda/ir/expressions/binaryExpression.cpp
+++ b/es2panda/ir/expressions/binaryExpression.cpp
@@ -43,13 +43,9 @@ void BinaryExpression::CompileLogical(compiler::PandaGen *pg) const
     compiler::RegScope rs(pg);
     compiler::VReg lhs = pg->AllocReg();
 
-    if (operator_ == lexer::TokenType::PUNCTUATOR_NULLISH_COALESCING) {
-        // TODO(parser): Nullish Coalesce
-        compiler::PandaGen::Unimplemented();
-    }
-
     ASSERT(operator_ == lexer::TokenType::PUNCTUATOR_LOGICAL_AND ||
-           operator_ == lexer::TokenType::PUNCTUATOR_LOGICAL_OR);
+           operator_ == lexer::TokenType::PUNCTUATOR_LOGICAL_OR ||
+           operator_ == lexer::TokenType::PUNCTUATOR_NULLISH_COALESCING);
     auto *skipRight = pg->AllocLabel();
     auto *endLabel = pg->AllocLabel();
 
@@ -59,9 +55,17 @@ void BinaryExpression::CompileLogical(compiler::PandaGen *pg) const
 
     if (operator_ == lexer::TokenType::PUNCTUATOR_LOGICAL_AND) {
         pg->BranchIfFalse(this, skipRight);
-    } else {
-        ASSERT(operator_ == lexer::TokenType::PUNCTUATOR_LOGICAL_OR);
+    } else if (operator_ == lexer::TokenType::PUNCTUATOR_LOGICAL_OR) {
         pg->BranchIfTrue(this, skipRight);
+    } else {
+        ASSERT(operator_ == lexer::TokenType::PUNCTUATOR_NULLISH_COALESCING);
+        auto *nullish = pg->AllocLabel();
+        // if lhs === null
+        pg->BranchIfStrictNull(this, nullish);
+        pg->LoadAccumulator(this, lhs);
+        // if lhs === undefined
+        pg->BranchIfStrictNotUndefined(this, skipRight);
+        pg->SetLabel(this, nullish);
     }
 
     // left is true/false(and/or) then right -> acc
diff --git a/es2panda/test/compiler/js/binaryExpression/nullishCoalesce-expected.txt b/es2panda/test/compiler/js/binaryExpression/nullishCoalesce-expected.txt
new file mode 100644
index 0000000000..294f02e8dc
--- /dev/null
+++ b/es2panda/test/compiler/js/binaryExpression/nullishCoalesce-expected.txt
@@ -0,0 +1,5 @@
+2
+4
+52
+4
+5
diff --git a/es2panda/test/compiler/js/binaryExpression/nullishCoalesce.js b/es2panda/test/compiler/js/binaryExpression/nullishCoalesce.js
new file mode 100644
index 0000000000..1d4d4f0208
--- /dev/null
+++ b/es2panda/test/compiler/js/binaryExpression/nullishCoalesce.js
@@ -0,0 +1,9 @@
+let a = 2;
+let b = a ?? 3;
+print(b);
+a = null;
+b = a ?? 4;
+print(b);
+a = undefined;
+b = a ?? 5;
+print(b);
-- 
Gitee