void ErlangGCPrinter::finishAssembly(Module &M, GCModuleInfo &Info, AsmPrinter &AP) { MCStreamer &OS = *AP.OutStreamer; unsigned IntPtrSize = M.getDataLayout().getPointerSize(); // Put this in a custom .note section. OS.SwitchSection( AP.getObjFileLowering().getContext().getELFSection(".note.gc", ELF::SHT_PROGBITS, 0)); // For each function... for (GCModuleInfo::FuncInfoVec::iterator FI = Info.funcinfo_begin(), IE = Info.funcinfo_end(); FI != IE; ++FI) { GCFunctionInfo &MD = **FI; if (MD.getStrategy().getName() != getStrategy().getName()) // this function is managed by some other GC continue; /** A compact GC layout. Emit this data structure: * * struct { * int16_t PointCount; * void *SafePointAddress[PointCount]; * int16_t StackFrameSize; (in words) * int16_t StackArity; * int16_t LiveCount; * int16_t LiveOffsets[LiveCount]; * } __gcmap_<FUNCTIONNAME>; **/ // Align to address width. AP.EmitAlignment(IntPtrSize == 4 ? 2 : 3); // Emit PointCount. OS.AddComment("safe point count"); AP.EmitInt16(MD.size()); // And each safe point... for (GCFunctionInfo::iterator PI = MD.begin(), PE = MD.end(); PI != PE; ++PI) { // Emit the address of the safe point. OS.AddComment("safe point address"); MCSymbol *Label = PI->Label; AP.EmitLabelPlusOffset(Label /*Hi*/, 0 /*Offset*/, 4 /*Size*/); } // Stack information never change in safe points! Only print info from the // first call-site. GCFunctionInfo::iterator PI = MD.begin(); // Emit the stack frame size. OS.AddComment("stack frame size (in words)"); AP.EmitInt16(MD.getFrameSize() / IntPtrSize); // Emit stack arity, i.e. the number of stacked arguments. unsigned RegisteredArgs = IntPtrSize == 4 ? 5 : 6; unsigned StackArity = MD.getFunction().arg_size() > RegisteredArgs ? MD.getFunction().arg_size() - RegisteredArgs : 0; OS.AddComment("stack arity"); AP.EmitInt16(StackArity); // Emit the number of live roots in the function. OS.AddComment("live root count"); AP.EmitInt16(MD.live_size(PI)); // And for each live root... for (GCFunctionInfo::live_iterator LI = MD.live_begin(PI), LE = MD.live_end(PI); LI != LE; ++LI) { // Emit live root's offset within the stack frame. OS.AddComment("stack index (offset / wordsize)"); AP.EmitInt16(LI->StackOffset / IntPtrSize); } } }
void RgcPrinter::finishAssembly(Module &M, GCModuleInfo &Info, AsmPrinter &AP) { MCStreamer &OS = AP.OutStreamer; unsigned IntPtrSize = AP.TM.getSubtargetImpl()->getDataLayout()->getPointerSize(); // Put this in the data section. OS.SwitchSection(AP.getObjFileLowering().getDataSection()); // For each function... for (GCModuleInfo::FuncInfoVec::iterator FI = Info.funcinfo_begin(), FE = Info.funcinfo_end(); FI != FE; ++FI) { GCFunctionInfo &MD = **FI; // A compact GC layout. Emit this data structure: // // struct { // int32_t PointCount; // void *SafePointAddress[PointCount]; // int32_t StackFrameSize; // in words // int32_t StackArity; // int32_t LiveCount; // int32_t LiveOffsets[LiveCount]; // } __gcmap_<FUNCTIONNAME>; // Align to address width. // AP.EmitAlignment(IntPtrSize == 4 ? 2 : 3); // Emit PointCount. OS.AddComment("safe point count"); AP.EmitInt32(MD.size()); // And each safe point... for (GCFunctionInfo::iterator PI = MD.begin(), PE = MD.end(); PI != PE; ++PI) { // Emit the address of the safe point. OS.AddComment("safe point address"); MCSymbol *Label = PI->Label; AP.EmitLabelPlusOffset(Label/*Hi*/, 0/*Offset*/, 4/*Size*/); } // Stack information never change in safe points! Only print info from the // first call-site. GCFunctionInfo::iterator PI = MD.begin(); // Emit the stack frame size. OS.AddComment("stack frame size (in words)"); AP.EmitInt32(MD.getFrameSize() / IntPtrSize); // Emit stack arity, i.e. the number of stacked arguments. unsigned RegisteredArgs = IntPtrSize == 4 ? 5 : 6; unsigned StackArity = MD.getFunction().arg_size() > RegisteredArgs ? MD.getFunction().arg_size() - RegisteredArgs : 0; OS.AddComment("stack arity"); AP.EmitInt32(StackArity); // Emit the number of live roots in the function. OS.AddComment("live root count"); AP.EmitInt32(MD.live_size(PI)); // And for each live root... for (GCFunctionInfo::live_iterator LI = MD.live_begin(PI), LE = MD.live_end(PI); LI != LE; ++LI) { // Emit live root's offset within the stack frame. OS.AddComment("stack index (offset / wordsize)"); AP.EmitInt32(LI->StackOffset); } } }