//
//===----------------------------------------------------------------------===//
-#ifndef X86ASMPRINTER_H
-#define X86ASMPRINTER_H
+#ifndef LLVM_LIB_TARGET_X86_X86ASMPRINTER_H
+#define LLVM_LIB_TARGET_X86_X86ASMPRINTER_H
#include "X86Subtarget.h"
#include "llvm/CodeGen/AsmPrinter.h"
#include "llvm/CodeGen/StackMaps.h"
#include "llvm/Target/TargetMachine.h"
+// Implemented in X86MCInstLower.cpp
+namespace {
+ class X86MCInstLower;
+}
+
namespace llvm {
class MCStreamer;
class MCSymbol;
void GenerateExportDirective(const MCSymbol *Sym, bool IsData);
+ // This utility class tracks the length of a stackmap instruction's 'shadow'.
+ // It is used by the X86AsmPrinter to ensure that the stackmap shadow
+ // invariants (i.e. no other stackmaps, patchpoints, or control flow within
+ // the shadow) are met, while outputting a minimal number of NOPs for padding.
+ //
+ // To minimise the number of NOPs used, the shadow tracker counts the number
+ // of instruction bytes output since the last stackmap. Only if there are too
+ // few instruction bytes to cover the shadow are NOPs used for padding.
+ class StackMapShadowTracker {
+ public:
+ StackMapShadowTracker(TargetMachine &TM);
+ ~StackMapShadowTracker();
+ void startFunction(MachineFunction &MF);
+ void count(MCInst &Inst, const MCSubtargetInfo &STI);
+
+ // Called to signal the start of a shadow of RequiredSize bytes.
+ void reset(unsigned RequiredSize) {
+ RequiredShadowSize = RequiredSize;
+ CurrentShadowSize = 0;
+ InShadow = true;
+ }
+
+ // Called before every stackmap/patchpoint, and at the end of basic blocks,
+ // to emit any necessary padding-NOPs.
+ void emitShadowPadding(MCStreamer &OutStreamer, const MCSubtargetInfo &STI);
+ private:
+ TargetMachine &TM;
+ std::unique_ptr<MCCodeEmitter> CodeEmitter;
+ bool InShadow;
+
+ // RequiredShadowSize holds the length of the shadow specified in the most
+ // recently encountered STACKMAP instruction.
+ // CurrentShadowSize counts the number of bytes encoded since the most
+ // recently encountered STACKMAP, stopping when that number is greater than
+ // or equal to RequiredShadowSize.
+ unsigned RequiredShadowSize, CurrentShadowSize;
+ };
+
+ StackMapShadowTracker SMShadowTracker;
+
+ // All instructions emitted by the X86AsmPrinter should use this helper
+ // method.
+ //
+ // This helper function invokes the SMShadowTracker on each instruction before
+ // outputting it to the OutStream. This allows the shadow tracker to minimise
+ // the number of NOPs used for stackmap padding.
+ void EmitAndCountInstruction(MCInst &Inst);
+
+ void InsertStackMapShadows(MachineFunction &MF);
+ void LowerSTACKMAP(const MachineInstr &MI);
+ void LowerPATCHPOINT(const MachineInstr &MI);
+
+ void LowerTlsAddr(X86MCInstLower &MCInstLowering, const MachineInstr &MI);
+
public:
explicit X86AsmPrinter(TargetMachine &TM, MCStreamer &Streamer)
- : AsmPrinter(TM, Streamer), SM(*this) {
+ : AsmPrinter(TM, Streamer), SM(*this), SMShadowTracker(TM) {
Subtarget = &TM.getSubtarget<X86Subtarget>();
}
void EmitInstruction(const MachineInstr *MI) override;
+ void EmitBasicBlockEnd(const MachineBasicBlock &MBB) override {
+ SMShadowTracker.emitShadowPadding(OutStreamer, getSubtargetInfo());
+ }
+
bool PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
unsigned AsmVariant, const char *ExtraCode,
raw_ostream &OS) override;