[decompiler] fixed blocks with params. (#1497)

It would previously assume the blocktype is "simple" (at most a single result value), but now also supports function signatures.
Also fixed it ignoring the validator result.

3 files changed, 16 insertions, 14 deletions

diff --git a/src/decompiler-ast.h b/src/decompiler-ast.h
index 9c269e3c..553c938b 100644
--- a/src/decompiler-ast.h
+++ b/src/decompiler-ast.h
@@ -141,7 +141,7 @@ struct AST {
 
   template<ExprType T> void Block(const BlockExprBase<T>& be, LabelType label) {
     mc.BeginBlock(label, be.block);
-    Construct(be.block.exprs, be.block.decl.GetNumResults(), false);
+    Construct(be.block.exprs, be.block.decl.GetNumResults(), be.block.decl.GetNumParams(), false);
     mc.EndBlock();
     InsertNode(NodeType::Expr, T, &be, 1);
   }
@@ -180,9 +180,9 @@ struct AST {
         auto ife = cast<IfExpr>(&e);
         value_stack_depth--;  // Condition.
         mc.BeginBlock(LabelType::Block, ife->true_);
-        Construct(ife->true_.exprs, ife->true_.decl.GetNumResults(), false);
+        Construct(ife->true_.exprs, ife->true_.decl.GetNumResults(), ife->true_.decl.GetNumParams(), false);
         if (!ife->false_.empty()) {
-          Construct(ife->false_, ife->true_.decl.GetNumResults(), false);
+          Construct(ife->false_, ife->true_.decl.GetNumResults(), ife->true_.decl.GetNumParams(), false);
         }
         mc.EndBlock();
         value_stack_depth++;  // Put Condition back.
@@ -214,12 +214,12 @@ struct AST {
     }
   }
 
-  void Construct(const ExprList& es, Index nresults, bool is_function_body) {
+  void Construct(const ExprList& es, Index nresults, Index nparams, bool is_function_body) {
     block_stack.push_back(cur_block_id);
     cur_block_id = blocks_closed.size();
     blocks_closed.push_back(false);
     auto start = exp_stack.size();
-    auto value_stack_depth_start = value_stack_depth;
+    auto value_stack_depth_start = value_stack_depth - nparams;
     auto value_stack_in_variables = value_stack_depth;
     bool unreachable = false;
     for (auto& e : es) {
diff --git a/src/decompiler.cc b/src/decompiler.cc
index 93e0043e..2de695c2 100644
--- a/src/decompiler.cc
+++ b/src/decompiler.cc
@@ -661,7 +661,7 @@ struct Decompiler {
   std::string InitExp(const ExprList &el) {
     assert(!el.empty());
     AST ast(mc, nullptr);
-    ast.Construct(el, 1, false);
+    ast.Construct(el, 1, 0, false);
     auto val = DecompileExpr(ast.exp_stack[0], nullptr);
     assert(ast.exp_stack.size() == 1 && val.v.size() == 1);
     return std::move(val.v[0]);
@@ -764,7 +764,7 @@ struct Decompiler {
       AST ast(mc, f);
       cur_ast = &ast;
       if (!is_import) {
-        ast.Construct(f->exprs, f->GetNumResults(), true);
+        ast.Construct(f->exprs, f->GetNumResults(), 0, true);
         lst.Track(ast.exp_stack[0]);
         lst.CheckLayouts();
       }
diff --git a/src/tools/wasm-decompile.cc b/src/tools/wasm-decompile.cc
index 62e69d45..74491e55 100644
--- a/src/tools/wasm-decompile.cc
+++ b/src/tools/wasm-decompile.cc
@@ -83,15 +83,17 @@ int ProgramMain(int argc, char** argv) {
     result = ReadBinaryIr(infile.c_str(), file_data.data(), file_data.size(),
                           options, &errors, &module);
     if (Succeeded(result)) {
+      ValidateOptions options(features);
+      result = ValidateModule(&module, &errors, options);
       if (Succeeded(result)) {
-        ValidateOptions options(features);
-        result = ValidateModule(&module, &errors, options);
+        result = GenerateNames(&module,
+                               static_cast<NameOpts>(NameOpts::AlphaNames));
+      }
+      if (Succeeded(result)) {
+        // Must be called after ReadBinaryIr & GenerateNames, and before
+        // ApplyNames, see comments at definition.
+        RenameAll(module);
       }
-      result = GenerateNames(&module,
-                             static_cast<NameOpts>(NameOpts::AlphaNames));
-      // Must be called after ReadBinaryIr & GenerateNames, and before
-      // ApplyNames, see comments at definition.
-      RenameAll(module);
       if (Succeeded(result)) {
         /* TODO(binji): This shouldn't fail; if a name can't be applied
          * (because the index is invalid, say) it should just be skipped. */