Merge pull request #6063 from ethereum/stackCompressorBuiltin

Take builtin functions into account in the compilability checker.

Changelog.md

@@ -18,6 +18,7 @@ Bugfixes:
  * Optimizer: Fix internal error related to unused tag removal across assemblies. This never generated any invalid code.
  * SMTChecker: Fixed crash when used with fixed-sized arrays.
  * Yul: Properly detect name clashes with functions before their declaration.
+ * Yul: Take builtin functions into account in the compilability checker.
 
 
 Build System:

libyul/CompilabilityChecker.cpp

@@ -40,13 +40,15 @@ std::map<YulString, int> CompilabilityChecker::run(std::shared_ptr<Dialect> _dia
 
 	solAssert(_dialect->flavour == AsmFlavour::Strict, "");
 
-	EVMDialect const& evmDialect = dynamic_cast<EVMDialect const&>(*_dialect);
+	solAssert(dynamic_cast<EVMDialect const*>(_dialect.get()), "");
+	shared_ptr<NoOutputEVMDialect> noOutputDialect = make_shared<NoOutputEVMDialect>(dynamic_pointer_cast<EVMDialect>(_dialect));
 
 	bool optimize = true;
 	yul::AsmAnalysisInfo analysisInfo =
-		yul::AsmAnalyzer::analyzeStrictAssertCorrect(_dialect, EVMVersion(), _ast);
+		yul::AsmAnalyzer::analyzeStrictAssertCorrect(noOutputDialect, EVMVersion(), _ast);
+
 	NoOutputAssembly assembly;
-	CodeTransform transform(assembly, analysisInfo, _ast, evmDialect, optimize);
+	CodeTransform transform(assembly, analysisInfo, _ast, *noOutputDialect, optimize);
 	try
 	{
 		transform(_ast);

libyul/backends/evm/EVMDialect.h

@@ -66,7 +66,7 @@ struct EVMDialect: public Dialect
 	/// Sets the current object. Used during code generation.
 	void setCurrentObject(Object const* _object);
 
-private:
+protected:
 	void addFunction(
 		std::string _name,
 		size_t _params,

libyul/backends/evm/NoOutputAssembly.cpp

@@ -141,3 +141,22 @@ AbstractAssembly::SubID NoOutputAssembly::appendData(bytes const&)
 {
 	return 1;
 }
+
+NoOutputEVMDialect::NoOutputEVMDialect(shared_ptr<EVMDialect> const& _copyFrom):
+	EVMDialect(_copyFrom->flavour, _copyFrom->providesObjectAccess())
+{
+	for (auto& fun: m_functions)
+	{
+		size_t parameters = fun.second.parameters.size();
+		size_t returns = fun.second.returns.size();
+		fun.second.generateCode = [=](FunctionCall const&, AbstractAssembly& _asm, std::function<void()> _visitArguments)
+		{
+			_visitArguments();
+			for (size_t i = 0; i < parameters; i++)
+				_asm.appendInstruction(dev::solidity::Instruction::POP);
+
+			for (size_t i = 0; i < returns; i++)
+				_asm.appendConstant(u256(0));
+		};
+	}
+}

libyul/backends/evm/NoOutputAssembly.h

@@ -22,6 +22,8 @@
 
 #include <libyul/backends/evm/AbstractAssembly.h>
 
+#include <libyul/backends/evm/EVMDialect.h>
+
 #include <libevmasm/LinkerObject.h>
 
 #include <map>
@@ -34,6 +36,7 @@ struct SourceLocation;
 namespace yul
 {
 
+
 /**
  * Assembly class that just ignores everything and only performs stack counting.
  * The purpose is to use this assembly for compilation dry-runs.
@@ -72,4 +75,14 @@ private:
 	int m_stackHeight = 0;
 };
 
+
+/**
+ * EVM dialect that does not generate any code.
+ */
+struct NoOutputEVMDialect: public EVMDialect
+{
+	explicit NoOutputEVMDialect(std::shared_ptr<EVMDialect> const& _copyFrom);
+};
+
+
 }

test/cmdlineTests/object_compiler/args

@@ -0,0 +1 @@
+--strict-assembly --optimize

test/cmdlineTests/object_compiler/exit

@@ -0,0 +1 @@
+0

test/cmdlineTests/object_compiler/input.sol

@@ -0,0 +1,17 @@
+object "MyContract" {
+  code {
+    // this is the constructor.
+    // store the creator in the first storage slot
+    sstore(0, caller())
+    // now return the runtime code using the special functions
+    datacopy(0, dataoffset("Runtime"), datasize("Runtime"))
+    return(0, datasize("Runtime"))
+  }
+  object "Runtime" {
+    code {
+      // runtime - just return the creator
+      mstore(0, sload(0))
+      return(0, 0x20)
+    }
+  }
+}

test/cmdlineTests/object_compiler/output

@@ -0,0 +1,65 @@
+
+======= object_compiler/input.sol (EVM) =======
+
+Pretty printed source:
+object "MyContract" {
+    code {
+        sstore(0, caller())
+        let _3 := datasize("Runtime")
+        datacopy(0, dataoffset("Runtime"), _3)
+        return(0, _3)
+    }
+    object "Runtime" {
+        code {
+            mstore(0, sload(0))
+            return(0, 0x20)
+        }
+    }
+}
+
+
+Binary representation:
+33600055600b806012600039806000f350fe60005460005260206000f3
+
+Text representation:
+    /* "object_compiler/input.sol":128:136   */
+  caller
+    /* "object_compiler/input.sol":125:126   */
+  0x00
+    /* "object_compiler/input.sol":118:137   */
+  sstore
+  dataSize(sub_0)
+    /* "object_compiler/input.sol":240:259   */
+  dup1
+  dataOffset(sub_0)
+    /* "object_compiler/input.sol":125:126   */
+  0x00
+    /* "object_compiler/input.sol":205:260   */
+  codecopy
+    /* "object_compiler/input.sol":275:294   */
+  dup1
+    /* "object_compiler/input.sol":125:126   */
+  0x00
+    /* "object_compiler/input.sol":265:295   */
+  return
+    /* "object_compiler/input.sol":29:299   */
+  pop
+stop
+
+sub_0: assembly {
+        /* "object_compiler/input.sol":397:398   */
+      0x00
+        /* "object_compiler/input.sol":391:399   */
+      sload
+        /* "object_compiler/input.sol":397:398   */
+      0x00
+        /* "object_compiler/input.sol":381:400   */
+      mstore
+        /* "object_compiler/input.sol":417:421   */
+      0x20
+        /* "object_compiler/input.sol":397:398   */
+      0x00
+        /* "object_compiler/input.sol":407:422   */
+      return
+}
+