[Outlining] StringifyWalker (#5772)

StringifyWalker is a new Walker with UnifiedExpressionVisitor. This walker performs a shallow visit of control-flow (try, if, block, loop) expressions and their simple expression siblings before then visiting the children of each control-flow expression in postorder. As a result, this walker un-nests nested control flow structures, so the expression visit order does not correspond to a normal postorder traversal of the function.

2 files changed, 128 insertions, 0 deletions

diff --git a/test/gtest/CMakeLists.txt b/test/gtest/CMakeLists.txt
index 27b7be621..5523bcb00 100644
--- a/test/gtest/CMakeLists.txt
+++ b/test/gtest/CMakeLists.txt
@@ -5,6 +5,7 @@ set(unittest_SOURCES
   cfg.cpp
   dfa_minimization.cpp
   possible-contents.cpp
+  stringify.cpp
   type-builder.cpp
   wat-lexer.cpp
 )
diff --git a/test/gtest/stringify.cpp b/test/gtest/stringify.cpp
new file mode 100644
index 000000000..b96235cb6
--- /dev/null
+++ b/test/gtest/stringify.cpp
@@ -0,0 +1,127 @@
+#include "ir/utils.h"
+#include "passes/stringify-walker.h"
+#include "print-test.h"
+#include "wasm.h"
+#include "gtest/gtest.h"
+
+using namespace wasm;
+
+using StringifyTest = PrintTest;
+
+TEST_F(StringifyTest, Print) {
+  auto moduleText = R"wasm(
+    (module
+    (tag $catch_a (param i32))
+    (tag $catch_b (param i32))
+    (tag $catch_c (param i32))
+    (func $d
+      (block $block_a
+        (drop (i32.const 20))
+        (drop (i32.const 10))
+      )
+      (block $block_b
+        (drop (if (i32.const 0)
+          (i32.const 40)
+          (i32.const 5)
+        ))
+      )
+      (block $block_c
+        (drop (if (i32.const 1)
+          (i32.const 30)
+        ))
+      )
+      (block $block_d
+        (try $try_a
+          (do
+            (nop)
+          )
+          (catch $catch_a
+            (drop (i32.const 8))
+          )
+          (catch $catch_b
+            (drop (i32.const 15))
+          )
+        )
+      )
+      (block $block_e
+        (try $try_b
+          (do
+            (nop)
+          )
+          (catch $catch_c
+            (drop (i32.const 33))
+          )
+        )
+      )
+    )
+   )
+  )wasm";
+
+  auto stringifyText = R"stringify(in visitExpression for block
+adding unique symbol
+in visitExpression for block $block_a
+in visitExpression for block $block_b
+in visitExpression for block $block_c
+in visitExpression for block $block_d
+in visitExpression for block $block_e
+adding unique symbol
+in visitExpression for i32.const 20
+in visitExpression for drop
+in visitExpression for i32.const 10
+in visitExpression for drop
+adding unique symbol
+in visitExpression for i32.const 0
+in visitExpression for if
+in visitExpression for drop
+adding unique symbol
+in visitExpression for i32.const 1
+in visitExpression for if
+in visitExpression for drop
+adding unique symbol
+in visitExpression for try $try_a
+adding unique symbol
+in visitExpression for try $try_b
+adding unique symbol
+in visitExpression for i32.const 40
+adding unique symbol
+in visitExpression for i32.const 5
+adding unique symbol
+in visitExpression for i32.const 30
+adding unique symbol
+in visitExpression for nop
+adding unique symbol
+in visitExpression for i32.const 8
+in visitExpression for drop
+adding unique symbol
+in visitExpression for i32.const 15
+in visitExpression for drop
+adding unique symbol
+in visitExpression for nop
+adding unique symbol
+in visitExpression for i32.const 33
+in visitExpression for drop
+adding unique symbol
+)stringify";
+
+  struct TestStringifyWalker : public StringifyWalker<TestStringifyWalker> {
+    std::ostream& os;
+
+    TestStringifyWalker(std::ostream& os) : os(os){};
+
+    void addUniqueSymbol() { os << "adding unique symbol\n"; }
+
+    void visitExpression(Expression* curr) {
+      os << "in visitExpression for " << ShallowExpression{curr, getModule()}
+         << std::endl;
+    }
+  };
+
+  Module wasm;
+  parseWast(wasm, moduleText);
+
+  std::stringstream ss;
+  TestStringifyWalker stringify = TestStringifyWalker(ss);
+  stringify.walkModule(&wasm);
+
+  EXPECT_EQ(ss.str(), stringifyText);
+}