Merge pull request #3721 from ethereum/simpleDynArray

Create empty dynamic memory arrays more efficiently.

1 files changed, 7 insertions, 0 deletions

diff --git a/libsolidity/codegen/CompilerUtils.h b/libsolidity/codegen/CompilerUtils.h
index 389673ef..a32c5c6e 100644
--- a/libsolidity/codegen/CompilerUtils.h
+++ b/libsolidity/codegen/CompilerUtils.h
@@ -210,6 +210,9 @@ public:
 	/// Creates a zero-value for the given type and puts it onto the stack. This might allocate
 	/// memory for memory references.
 	void pushZeroValue(Type const& _type);
+	/// Pushes a pointer to the stack that points to a (potentially shared) location in memory
+	/// that always contains a zero. It is not allowed to write there.
+	void pushZeroPointer();
 
 	/// Moves the value that is at the top of the stack to a stack variable.
 	void moveToStackVariable(VariableDeclaration const& _variable);
@@ -255,6 +258,10 @@ public:
 
 	/// Position of the free-memory-pointer in memory;
 	static const size_t freeMemoryPointer;
+	/// Position of the memory slot that is always zero.
+	static const size_t zeroPointer;
+	/// Starting offset for memory available to the user (aka the contract).
+	static const size_t generalPurposeMemoryStart;
 
 private:
 	/// Address of the precompiled identity contract.