Make generated code loading constants relocatable

On 32-bit architectures we were encoding the absolute address of generated
constants in memory into the load instruction. In order to make the code
reloctable, this patch changes the JIT over to use the constant table in the
compilation unit. This means two additional loads per constant. On
architectures that support instruction pointer relative addressing, we can try
to fix this in the future (arm32 for example).

Change-Id: I8ed7aa7c67711696d6c46c72b3b642d610ff2cbc
Reviewed-by: Erik Verbruggen <erik.verbruggen@qt.io>

1 files changed, 4 insertions, 0 deletions

diff --git a/src/qml/jsruntime/qv4script_p.h b/src/qml/jsruntime/qv4script_p.h
index e81bc3049c..2e87a7692b 100644
--- a/src/qml/jsruntime/qv4script_p.h
+++ b/src/qml/jsruntime/qv4script_p.h
@@ -71,6 +71,7 @@ struct ContextStateSaver {
     Value *savedContext;
     bool strictMode;
     Lookup *lookups;
+    const QV4::Value *constantTable;
     CompiledData::CompilationUnit *compilationUnit;
     int lineNumber;
 
@@ -78,6 +79,7 @@ struct ContextStateSaver {
         : savedContext(scope.alloc(1))
         , strictMode(context->d()->strictMode)
         , lookups(context->d()->lookups)
+        , constantTable(context->d()->constantTable)
         , compilationUnit(context->d()->compilationUnit)
         , lineNumber(context->d()->lineNumber)
     {
@@ -87,6 +89,7 @@ struct ContextStateSaver {
         : savedContext(scope.alloc(1))
         , strictMode(context->strictMode)
         , lookups(context->lookups)
+        , constantTable(context->constantTable)
         , compilationUnit(context->compilationUnit)
         , lineNumber(context->lineNumber)
     {
@@ -98,6 +101,7 @@ struct ContextStateSaver {
         Heap::ExecutionContext *ctx = static_cast<Heap::ExecutionContext *>(savedContext->m());
         ctx->strictMode = strictMode;
         ctx->lookups = lookups;
+        ctx->constantTable = constantTable;
         ctx->compilationUnit = compilationUnit;
         ctx->lineNumber = lineNumber;
     }