Add support for proper lexical scoping

This is still to some extend work in progress as
lexically scoped for loops won't yet do the right
thing.

let and const variables are still accessible before
they are declared, and the global scope doesn't yet
have a proper context for lexically declared variables.

Change-Id: Ie39f74a8fccdaead437fbf07f9fc228a444c26ed
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

1 files changed, 46 insertions, 6 deletions

diff --git a/src/qml/compiler/qv4compiler.cpp b/src/qml/compiler/qv4compiler.cpp
index d9f37b542f..d5b77f61cb 100644
--- a/src/qml/compiler/qv4compiler.cpp
+++ b/src/qml/compiler/qv4compiler.cpp
@@ -233,28 +233,39 @@ QV4::CompiledData::Unit *QV4::Compiler::JSUnitGenerator::generateUnit(GeneratorO
         for (int i = 0; i < f->locals.size(); ++i)
             registerString(f->locals.at(i));
     }
+    for (Context *c : qAsConst(module->blocks)) {
+        for (int i = 0; i < c->locals.size(); ++i)
+            registerString(c->locals.at(i));
+    }
 
-    Q_ALLOCA_VAR(quint32_le, functionOffsets, module->functions.size() * sizeof(quint32_le));
+    Q_ALLOCA_VAR(quint32_le, blockAndFunctionOffsets, (module->functions.size() + module->blocks.size()) * sizeof(quint32_le));
     uint jsClassDataOffset = 0;
 
     char *dataPtr;
     CompiledData::Unit *unit;
     {
-        QV4::CompiledData::Unit tempHeader = generateHeader(option, functionOffsets, &jsClassDataOffset);
+        QV4::CompiledData::Unit tempHeader = generateHeader(option, blockAndFunctionOffsets, &jsClassDataOffset);
         dataPtr = reinterpret_cast<char *>(malloc(tempHeader.unitSize));
         memset(dataPtr, 0, tempHeader.unitSize);
         memcpy(&unit, &dataPtr, sizeof(CompiledData::Unit*));
         memcpy(unit, &tempHeader, sizeof(tempHeader));
     }
 
-    memcpy(dataPtr + unit->offsetToFunctionTable, functionOffsets, unit->functionTableSize * sizeof(quint32_le));
+    memcpy(dataPtr + unit->offsetToFunctionTable, blockAndFunctionOffsets, unit->functionTableSize * sizeof(quint32_le));
+    memcpy(dataPtr + unit->offsetToBlockTable, blockAndFunctionOffsets + unit->functionTableSize, unit->blockTableSize * sizeof(quint32_le));
 
     for (int i = 0; i < module->functions.size(); ++i) {
         Context *function = module->functions.at(i);
         if (function == module->rootContext)
             unit->indexOfRootFunction = i;
 
-        writeFunction(dataPtr + functionOffsets[i], function);
+        writeFunction(dataPtr + blockAndFunctionOffsets[i], function);
+    }
+
+    for (int i = 0; i < module->blocks.size(); ++i) {
+        Context *block = module->blocks.at(i);
+
+        writeBlock(dataPtr + blockAndFunctionOffsets[i + module->functions.size()], block);
     }
 
     CompiledData::Lookup *lookupsToWrite = reinterpret_cast<CompiledData::Lookup*>(dataPtr + unit->offsetToLookupTable);
@@ -395,7 +406,24 @@ void QV4::Compiler::JSUnitGenerator::writeFunction(char *f, QV4::Compiler::Conte
     memcpy(f + function->codeOffset, irFunction->code.constData(), irFunction->code.size());
 }
 
-QV4::CompiledData::Unit QV4::Compiler::JSUnitGenerator::generateHeader(QV4::Compiler::JSUnitGenerator::GeneratorOption option, quint32_le *functionOffsets, uint *jsClassDataOffset)
+void QV4::Compiler::JSUnitGenerator::writeBlock(char *b, QV4::Compiler::Context *irBlock) const
+{
+    QV4::CompiledData::Block *block = reinterpret_cast<QV4::CompiledData::Block *>(b);
+
+    quint32 currentOffset = sizeof(QV4::CompiledData::Block);
+    currentOffset = (currentOffset + 7) & ~quint32(0x7);
+
+    block->nLocals = irBlock->locals.size();
+    block->localsOffset = currentOffset;
+    currentOffset += block->nLocals * sizeof(quint32);
+
+    // write locals
+    quint32_le *locals = (quint32_le *)(b + block->localsOffset);
+    for (int i = 0; i < irBlock->locals.size(); ++i)
+        locals[i] = getStringId(irBlock->locals.at(i));
+}
+
+QV4::CompiledData::Unit QV4::Compiler::JSUnitGenerator::generateHeader(QV4::Compiler::JSUnitGenerator::GeneratorOption option, quint32_le *blockAndFunctionOffsets, uint *jsClassDataOffset)
 {
     CompiledData::Unit unit;
     memset(&unit, 0, sizeof(unit));
@@ -414,6 +442,10 @@ QV4::CompiledData::Unit QV4::Compiler::JSUnitGenerator::generateHeader(QV4::Comp
     unit.offsetToFunctionTable = nextOffset;
     nextOffset += unit.functionTableSize * sizeof(uint);
 
+    unit.blockTableSize = module->blocks.size();
+    unit.offsetToBlockTable = nextOffset;
+    nextOffset += unit.blockTableSize * sizeof(uint);
+
     unit.lookupTableSize = lookups.count();
     unit.offsetToLookupTable = nextOffset;
     nextOffset += unit.lookupTableSize * sizeof(CompiledData::Lookup);
@@ -440,13 +472,21 @@ QV4::CompiledData::Unit QV4::Compiler::JSUnitGenerator::generateHeader(QV4::Comp
 
     for (int i = 0; i < module->functions.size(); ++i) {
         Context *f = module->functions.at(i);
-        functionOffsets[i] = nextOffset;
+        blockAndFunctionOffsets[i] = nextOffset;
 
         const int qmlIdDepsCount = f->idObjectDependencies.count();
         const int qmlPropertyDepsCount = f->scopeObjectPropertyDependencies.count() + f->contextObjectPropertyDependencies.count();
         nextOffset += QV4::CompiledData::Function::calculateSize(f->arguments.size(), f->locals.size(), f->lineNumberMapping.size(), f->nestedContexts.size(),
                                                                  qmlIdDepsCount, qmlPropertyDepsCount, f->code.size());
     }
+    blockAndFunctionOffsets += module->functions.size();
+
+    for (int i = 0; i < module->blocks.size(); ++i) {
+        Context *c = module->blocks.at(i);
+        blockAndFunctionOffsets[i] = nextOffset;
+
+        nextOffset += QV4::CompiledData::Block::calculateSize(c->locals.size());
+    }
 
     if (option == GenerateWithStringTable) {
         unit.stringTableSize = stringTable.stringCount();