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Create empty dynamic memory arrays more efficiently.

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chriseth authored and Alex Beregszaszi committed 2018-04-04 12:37:04 +02:00
1 parent c63efebd45
commit 0cbe55005d
8 files changed
+107 -20
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libsolidity/codegen/CompilerUtils.cpp
+22 -8
View File
@@ -21,6 +21,7 @@
*/
#include <libsolidity/codegen/CompilerUtils.h>
#include <libsolidity/ast/AST.h>
#include <libsolidity/codegen/ArrayUtils.h>
#include <libsolidity/codegen/LValue.h>
@@ -39,11 +40,17 @@ namespace solidity
const unsigned CompilerUtils::dataStartOffset = 4;
const size_t CompilerUtils::freeMemoryPointer = 64;
const size_t CompilerUtils::zeroPointer = CompilerUtils::freeMemoryPointer + 32;
const size_t CompilerUtils::generalPurposeMemoryStart = CompilerUtils::zeroPointer + 32;
const unsigned CompilerUtils::identityContractAddress = 4;
static_assert(CompilerUtils::freeMemoryPointer >= 64, "Free memory pointer must not overlap with scratch area.");
static_assert(CompilerUtils::zeroPointer >= CompilerUtils::freeMemoryPointer + 32, "Zero pointer must not overlap with free memory pointer.");
static_assert(CompilerUtils::generalPurposeMemoryStart >= CompilerUtils::zeroPointer + 32, "General purpose memory must not overlap with zero area.");
void CompilerUtils::initialiseFreeMemoryPointer()
{
m_context << u256(freeMemoryPointer + 32);
m_context << u256(generalPurposeMemoryStart);
storeFreeMemoryPointer();
}
@@ -1051,6 +1058,13 @@ void CompilerUtils::pushZeroValue(Type const& _type)
return;
}
solAssert(referenceType->location() == DataLocation::Memory, "");
if (auto arrayType = dynamic_cast<ArrayType const*>(&_type))
if (arrayType->isDynamicallySized())
{
// Push a memory location that is (hopefully) always zero.
pushZeroPointer();
return;
}
TypePointer type = _type.shared_from_this();
m_context.callLowLevelFunction(
@@ -1071,13 +1085,8 @@ void CompilerUtils::pushZeroValue(Type const& _type)
}
else if (auto arrayType = dynamic_cast<ArrayType const*>(type.get()))
{
if (arrayType->isDynamicallySized())
{
// zero length
_context << u256(0);
utils.storeInMemoryDynamic(IntegerType(256));
}
else if (arrayType->length() > 0)
solAssert(!arrayType->isDynamicallySized(), "");
if (arrayType->length() > 0)
{
_context << arrayType->length() << Instruction::SWAP1;
// stack: items_to_do memory_pos
@@ -1094,6 +1103,11 @@ void CompilerUtils::pushZeroValue(Type const& _type)
);
}
void CompilerUtils::pushZeroPointer()
{
m_context << u256(zeroPointer);
}
void CompilerUtils::moveToStackVariable(VariableDeclaration const& _variable)
{
unsigned const stackPosition = m_context.baseToCurrentStackOffset(m_context.baseStackOffsetOfVariable(_variable));