llvm/lib/Target/Alpha/AlphaJITInfo.cpp - toolchain/llvm-project - Gitiles

 //===-- AlphaJITInfo.cpp - Implement the JIT interfaces for the Alpha ---===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file implements the JIT interfaces for the Alpha target.
 //
 //===----------------------------------------------------------------------===//

 #define DEBUG_TYPE "jit"
 #include "AlphaJITInfo.h"
 #include "AlphaRelocations.h"
 #include "llvm/Function.h"
 #include "llvm/CodeGen/JITCodeEmitter.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/raw_ostream.h"
 #include <cstdlib>
 using namespace llvm;

 #define BUILD_OFormatI(Op, RA, LIT, FUN, RC) \
   ((Op << 26) | (RA << 21) | (LIT << 13) | (1 << 12) | (FUN << 5) | (RC))
 #define BUILD_OFormat(Op, RA, RB, FUN, RC) \
   ((Op << 26) | (RA << 21) | (RB << 16) | (FUN << 5) | (RC))

 #define BUILD_LDA(RD, RS, IMM16) \
   ((0x08 << 26) | ((RD) << 21) | ((RS) << 16) | ((IMM16) & 65535))
 #define BUILD_LDAH(RD, RS, IMM16) \
   ((0x09 << 26) | ((RD) << 21) | ((RS) << 16) | ((IMM16) & 65535))

 #define BUILD_LDQ(RD, RS, IMM16) \
   ((0x29 << 26) | ((RD) << 21) | ((RS) << 16) | ((IMM16) & 0xFFFF))

 #define BUILD_JMP(RD, RS, IMM16) \
   ((0x1A << 26) | ((RD) << 21) | ((RS) << 16) | (0x00 << 14) | ((IMM16) & 0x3FFF))
 #define BUILD_JSR(RD, RS, IMM16) \
   ((0x1A << 26) | ((RD) << 21) | ((RS) << 16) | (0x01 << 14) | ((IMM16) & 0x3FFF))

 #define BUILD_SLLi(RD, RS, IMM8) \
   (BUILD_OFormatI(0x12, RS, IMM8, 0x39, RD))

 #define BUILD_ORi(RD, RS, IMM8) \
   (BUILD_OFormatI(0x11, RS, IMM8, 0x20, RD))

 #define BUILD_OR(RD, RS, RT) \
   (BUILD_OFormat(0x11, RS, RT, 0x20, RD))


 static void EmitBranchToAt(void *At, void *To) {
   unsigned long Fn = (unsigned long)To;

   unsigned *AtI = (unsigned*)At;

   AtI[0] = BUILD_OR(0, 27, 27);

   DEBUG(errs() << "Stub targeting " << To << "\n");

   for (int x = 1; x <= 8; ++x) {
     AtI[2*x - 1] = BUILD_SLLi(27,27,8);
     unsigned d = (Fn >> (64 - 8 * x)) & 0x00FF;
     //DEBUG(errs() << "outputing " << hex << d << dec << "\n");
     AtI[2*x] = BUILD_ORi(27, 27, d);
   }
   AtI[17] = BUILD_JMP(31,27,0); //jump, preserving ra, and setting pv
   AtI[18] = 0x00FFFFFF; //mark this as a stub
 }

 void AlphaJITInfo::replaceMachineCodeForFunction(void *Old, void *New) {
   //FIXME
   llvm_unreachable(0);
 }

 static TargetJITInfo::JITCompilerFn JITCompilerFunction;
 //static AlphaJITInfo* AlphaJTI;

 extern "C" {
 #ifdef __alpha

   void AlphaCompilationCallbackC(long* oldpv, void* CameFromStub)
   {
     void* Target = JITCompilerFunction(CameFromStub);

     //rewrite the stub to an unconditional branch
     if (((unsigned*)CameFromStub)[18] == 0x00FFFFFF) {
       DEBUG(errs() << "Came from a stub, rewriting\n");
       EmitBranchToAt(CameFromStub, Target);
     } else {
       DEBUG(errs() << "confused, didn't come from stub at " << CameFromStub
                    << " old jump vector " << oldpv
                    << " new jump vector " << Target << "\n");
     }

     //Change pv to new Target
     *oldpv = (long)Target;
   }

   void AlphaCompilationCallback(void);

   asm(
       ".text\n"
       ".globl AlphaCompilationCallbackC\n"
       ".align 4\n"
       ".globl AlphaCompilationCallback\n"
       ".ent AlphaCompilationCallback\n"
 "AlphaCompilationCallback:\n"
       //      //get JIT's GOT
       "ldgp $29, 0($27)\n"
       //Save args, callee saved, and perhaps others?
       //args: $16-$21 $f16-$f21     (12)
       //callee: $9-$14 $f2-$f9      (14)
       //others: fp:$15 ra:$26 pv:$27 (3)
       "lda $30, -232($30)\n"
       "stq $16,   0($30)\n"
       "stq $17,   8($30)\n"
       "stq $18,  16($30)\n"
       "stq $19,  24($30)\n"
       "stq $20,  32($30)\n"
       "stq $21,  40($30)\n"
       "stt $f16, 48($30)\n"
       "stt $f17, 56($30)\n"
       "stt $f18, 64($30)\n"
       "stt $f19, 72($30)\n"
       "stt $f20, 80($30)\n"
       "stt $f21, 88($30)\n"
       "stq $9,   96($30)\n"
       "stq $10, 104($30)\n"
       "stq $11, 112($30)\n"
       "stq $12, 120($30)\n"
       "stq $13, 128($30)\n"
       "stq $14, 136($30)\n"
       "stt $f2, 144($30)\n"
       "stt $f3, 152($30)\n"
       "stt $f4, 160($30)\n"
       "stt $f5, 168($30)\n"
       "stt $f6, 176($30)\n"
       "stt $f7, 184($30)\n"
       "stt $f8, 192($30)\n"
       "stt $f9, 200($30)\n"
       "stq $15, 208($30)\n"
       "stq $26, 216($30)\n"
       "stq $27, 224($30)\n"

       "addq $30, 224, $16\n" //pass the addr of saved pv as the first arg
       "bis $0, $0, $17\n" //pass the roughly stub addr in second arg
       "jsr $26, AlphaCompilationCallbackC\n" //call without saving ra

       "ldq $16,   0($30)\n"
       "ldq $17,   8($30)\n"
       "ldq $18,  16($30)\n"
       "ldq $19,  24($30)\n"
       "ldq $20,  32($30)\n"
       "ldq $21,  40($30)\n"
       "ldt $f16, 48($30)\n"
       "ldt $f17, 56($30)\n"
       "ldt $f18, 64($30)\n"
       "ldt $f19, 72($30)\n"
       "ldt $f20, 80($30)\n"
       "ldt $f21, 88($30)\n"
       "ldq $9,   96($30)\n"
       "ldq $10, 104($30)\n"
       "ldq $11, 112($30)\n"
       "ldq $12, 120($30)\n"
       "ldq $13, 128($30)\n"
       "ldq $14, 136($30)\n"
       "ldt $f2, 144($30)\n"
       "ldt $f3, 152($30)\n"
       "ldt $f4, 160($30)\n"
       "ldt $f5, 168($30)\n"
       "ldt $f6, 176($30)\n"
       "ldt $f7, 184($30)\n"
       "ldt $f8, 192($30)\n"
       "ldt $f9, 200($30)\n"
       "ldq $15, 208($30)\n"
       "ldq $26, 216($30)\n"
       "ldq $27, 224($30)\n" //this was updated in the callback with the target

       "lda $30, 232($30)\n" //restore sp
       "jmp $31, ($27)\n" //jump to the new function
       ".end AlphaCompilationCallback\n"
       );
 #else
   void AlphaCompilationCallback() {
     llvm_unreachable("Cannot call AlphaCompilationCallback() on a non-Alpha arch!");
   }
 #endif
 }

 TargetJITInfo::StubLayout AlphaJITInfo::getStubLayout() {
   // The stub contains 19 4-byte instructions, aligned at 4 bytes:
   // R0 = R27
   // 8 x "R27 <<= 8; R27 |= 8-bits-of-Target"  == 16 instructions
   // JMP R27
   // Magic number so the compilation callback can recognize the stub.
   StubLayout Result = {19 * 4, 4};
   return Result;
 }

 void *AlphaJITInfo::emitFunctionStub(const Function* F, void *Fn,
                                      JITCodeEmitter &JCE) {
   //assert(Fn == AlphaCompilationCallback && "Where are you going?\n");
   //Do things in a stupid slow way!
   void* Addr = (void*)(intptr_t)JCE.getCurrentPCValue();
   for (int x = 0; x < 19; ++ x)
     JCE.emitWordLE(0);
   EmitBranchToAt(Addr, Fn);
   DEBUG(errs() << "Emitting Stub to " << Fn << " at [" << Addr << "]\n");
   return Addr;
 }

 TargetJITInfo::LazyResolverFn
 AlphaJITInfo::getLazyResolverFunction(JITCompilerFn F) {
   JITCompilerFunction = F;
   //  setZerothGOTEntry((void*)AlphaCompilationCallback);
   return AlphaCompilationCallback;
 }

 //These describe LDAx
 static const int IMM_LOW  = -32768;
 static const int IMM_HIGH = 32767;
 static const int IMM_MULT = 65536;

 static long getUpper16(long l)
 {
   long y = l / IMM_MULT;
   if (l % IMM_MULT > IMM_HIGH)
     ++y;
   if (l % IMM_MULT < IMM_LOW)
     --y;
   assert((short)y == y && "displacement out of range");
   return y;
 }

 static long getLower16(long l)
 {
   long h = getUpper16(l);
   long y = l - h * IMM_MULT;
   assert(y == (short)y && "Displacement out of range");
   return y;
 }

 void AlphaJITInfo::relocate(void *Function, MachineRelocation *MR,
                             unsigned NumRelocs, unsigned char* GOTBase) {
   for (unsigned i = 0; i != NumRelocs; ++i, ++MR) {
     unsigned *RelocPos = (unsigned*)Function + MR->getMachineCodeOffset()/4;
     long idx = 0;
     bool doCommon = true;
     switch ((Alpha::RelocationType)MR->getRelocationType()) {
     default: llvm_unreachable("Unknown relocation type!");
     case Alpha::reloc_literal:
       //This is a LDQl
       idx = MR->getGOTIndex();
       DEBUG(errs() << "Literal relocation to slot " << idx);
       idx = (idx - GOToffset) * 8;
       DEBUG(errs() << " offset " << idx << "\n");
       break;
     case Alpha::reloc_gprellow:
       idx = (unsigned char*)MR->getResultPointer() - &GOTBase[GOToffset * 8];
       idx = getLower16(idx);
       DEBUG(errs() << "gprellow relocation offset " << idx << "\n");
       DEBUG(errs() << " Pointer is " << (void*)MR->getResultPointer()
            << " GOT is " << (void*)&GOTBase[GOToffset * 8] << "\n");
       break;
     case Alpha::reloc_gprelhigh:
       idx = (unsigned char*)MR->getResultPointer() - &GOTBase[GOToffset * 8];
       idx = getUpper16(idx);
       DEBUG(errs() << "gprelhigh relocation offset " << idx << "\n");
       DEBUG(errs() << " Pointer is " << (void*)MR->getResultPointer()
             << " GOT is " << (void*)&GOTBase[GOToffset * 8] << "\n");
       break;
     case Alpha::reloc_gpdist:
       switch (*RelocPos >> 26) {
       case 0x09: //LDAH
         idx = &GOTBase[GOToffset * 8] - (unsigned char*)RelocPos;
         idx = getUpper16(idx);
         DEBUG(errs() << "LDAH: " << idx << "\n");
         //add the relocation to the map
         gpdistmap[std::make_pair(Function, MR->getConstantVal())] = RelocPos;
         break;
       case 0x08: //LDA
         assert(gpdistmap[std::make_pair(Function, MR->getConstantVal())] &&
                "LDAg without seeing LDAHg");
         idx = &GOTBase[GOToffset * 8] -
           (unsigned char*)gpdistmap[std::make_pair(Function, MR->getConstantVal())];
         idx = getLower16(idx);
         DEBUG(errs() << "LDA: " << idx << "\n");
         break;
       default:
         llvm_unreachable("Cannot handle gpdist yet");
       }
       break;
     case Alpha::reloc_bsr: {
       idx = (((unsigned char*)MR->getResultPointer() -
              (unsigned char*)RelocPos) >> 2) + 1; //skip first 2 inst of fun
       *RelocPos |= (idx & ((1 << 21)-1));
       doCommon = false;
       break;
     }
     }
     if (doCommon) {
       short x = (short)idx;
       assert(x == idx);
       *(short*)RelocPos = x;
     }
   }
 }
	//===-- AlphaJITInfo.cpp - Implement the JIT interfaces for the Alpha ---===//
	//
	// The LLVM Compiler Infrastructure
	//
	// This file is distributed under the University of Illinois Open Source
	// License. See LICENSE.TXT for details.
	//
	//===----------------------------------------------------------------------===//
	//
	// This file implements the JIT interfaces for the Alpha target.
	//
	//===----------------------------------------------------------------------===//

	#define DEBUG_TYPE "jit"
	#include "AlphaJITInfo.h"
	#include "AlphaRelocations.h"
	#include "llvm/Function.h"
	#include "llvm/CodeGen/JITCodeEmitter.h"
	#include "llvm/Support/Debug.h"
	#include "llvm/Support/ErrorHandling.h"
	#include "llvm/Support/raw_ostream.h"
	#include <cstdlib>
	using namespace llvm;

	#define BUILD_OFormatI(Op, RA, LIT, FUN, RC) \
	((Op << 26) \| (RA << 21) \| (LIT << 13) \| (1 << 12) \| (FUN << 5) \| (RC))
	#define BUILD_OFormat(Op, RA, RB, FUN, RC) \
	((Op << 26) \| (RA << 21) \| (RB << 16) \| (FUN << 5) \| (RC))

	#define BUILD_LDA(RD, RS, IMM16) \
	((0x08 << 26) \| ((RD) << 21) \| ((RS) << 16) \| ((IMM16) & 65535))
	#define BUILD_LDAH(RD, RS, IMM16) \
	((0x09 << 26) \| ((RD) << 21) \| ((RS) << 16) \| ((IMM16) & 65535))

	#define BUILD_LDQ(RD, RS, IMM16) \
	((0x29 << 26) \| ((RD) << 21) \| ((RS) << 16) \| ((IMM16) & 0xFFFF))

	#define BUILD_JMP(RD, RS, IMM16) \
	((0x1A << 26) \| ((RD) << 21) \| ((RS) << 16) \| (0x00 << 14) \| ((IMM16) & 0x3FFF))
	#define BUILD_JSR(RD, RS, IMM16) \
	((0x1A << 26) \| ((RD) << 21) \| ((RS) << 16) \| (0x01 << 14) \| ((IMM16) & 0x3FFF))

	#define BUILD_SLLi(RD, RS, IMM8) \
	(BUILD_OFormatI(0x12, RS, IMM8, 0x39, RD))

	#define BUILD_ORi(RD, RS, IMM8) \
	(BUILD_OFormatI(0x11, RS, IMM8, 0x20, RD))

	#define BUILD_OR(RD, RS, RT) \
	(BUILD_OFormat(0x11, RS, RT, 0x20, RD))



	static void EmitBranchToAt(void At, void To) {
	unsigned long Fn = (unsigned long)To;

	unsigned AtI = (unsigned)At;

	AtI[0] = BUILD_OR(0, 27, 27);

	DEBUG(errs() << "Stub targeting " << To << "\n");

	for (int x = 1; x <= 8; ++x) {
	AtI[2*x - 1] = BUILD_SLLi(27,27,8);
	unsigned d = (Fn >> (64 - 8 * x)) & 0x00FF;
	//DEBUG(errs() << "outputing " << hex << d << dec << "\n");
	AtI[2*x] = BUILD_ORi(27, 27, d);
	}
	AtI[17] = BUILD_JMP(31,27,0); //jump, preserving ra, and setting pv
	AtI[18] = 0x00FFFFFF; //mark this as a stub
	}

	void AlphaJITInfo::replaceMachineCodeForFunction(void Old, void New) {
	//FIXME
	llvm_unreachable(0);
	}

	static TargetJITInfo::JITCompilerFn JITCompilerFunction;
	//static AlphaJITInfo* AlphaJTI;

	extern "C" {
	#ifdef __alpha

	void AlphaCompilationCallbackC(long* oldpv, void* CameFromStub)
	{
	void* Target = JITCompilerFunction(CameFromStub);

	//rewrite the stub to an unconditional branch
	if (((unsigned*)CameFromStub)[18] == 0x00FFFFFF) {
	DEBUG(errs() << "Came from a stub, rewriting\n");
	EmitBranchToAt(CameFromStub, Target);
	} else {
	DEBUG(errs() << "confused, didn't come from stub at " << CameFromStub
	<< " old jump vector " << oldpv
	<< " new jump vector " << Target << "\n");
	}

	//Change pv to new Target
	*oldpv = (long)Target;
	}

	void AlphaCompilationCallback(void);

	asm(
	".text\n"
	".globl AlphaCompilationCallbackC\n"
	".align 4\n"
	".globl AlphaCompilationCallback\n"
	".ent AlphaCompilationCallback\n"
	"AlphaCompilationCallback:\n"
	// //get JIT's GOT
	"ldgp $29, 0($27)\n"
	//Save args, callee saved, and perhaps others?
	//args: $16-$21 $f16-$f21 (12)
	//callee: $9-$14 $f2-$f9 (14)
	//others: fp:$15 ra:$26 pv:$27 (3)
	"lda $30, -232($30)\n"
	"stq $16, 0($30)\n"
	"stq $17, 8($30)\n"
	"stq $18, 16($30)\n"
	"stq $19, 24($30)\n"
	"stq $20, 32($30)\n"
	"stq $21, 40($30)\n"
	"stt $f16, 48($30)\n"
	"stt $f17, 56($30)\n"
	"stt $f18, 64($30)\n"
	"stt $f19, 72($30)\n"
	"stt $f20, 80($30)\n"
	"stt $f21, 88($30)\n"
	"stq $9, 96($30)\n"
	"stq $10, 104($30)\n"
	"stq $11, 112($30)\n"
	"stq $12, 120($30)\n"
	"stq $13, 128($30)\n"
	"stq $14, 136($30)\n"
	"stt $f2, 144($30)\n"
	"stt $f3, 152($30)\n"
	"stt $f4, 160($30)\n"
	"stt $f5, 168($30)\n"
	"stt $f6, 176($30)\n"
	"stt $f7, 184($30)\n"
	"stt $f8, 192($30)\n"
	"stt $f9, 200($30)\n"
	"stq $15, 208($30)\n"
	"stq $26, 216($30)\n"
	"stq $27, 224($30)\n"

	"addq $30, 224, $16\n" //pass the addr of saved pv as the first arg
	"bis $0, $0, $17\n" //pass the roughly stub addr in second arg
	"jsr $26, AlphaCompilationCallbackC\n" //call without saving ra

	"ldq $16, 0($30)\n"
	"ldq $17, 8($30)\n"
	"ldq $18, 16($30)\n"
	"ldq $19, 24($30)\n"
	"ldq $20, 32($30)\n"
	"ldq $21, 40($30)\n"
	"ldt $f16, 48($30)\n"
	"ldt $f17, 56($30)\n"
	"ldt $f18, 64($30)\n"
	"ldt $f19, 72($30)\n"
	"ldt $f20, 80($30)\n"
	"ldt $f21, 88($30)\n"
	"ldq $9, 96($30)\n"
	"ldq $10, 104($30)\n"
	"ldq $11, 112($30)\n"
	"ldq $12, 120($30)\n"
	"ldq $13, 128($30)\n"
	"ldq $14, 136($30)\n"
	"ldt $f2, 144($30)\n"
	"ldt $f3, 152($30)\n"
	"ldt $f4, 160($30)\n"
	"ldt $f5, 168($30)\n"
	"ldt $f6, 176($30)\n"
	"ldt $f7, 184($30)\n"
	"ldt $f8, 192($30)\n"
	"ldt $f9, 200($30)\n"
	"ldq $15, 208($30)\n"
	"ldq $26, 216($30)\n"
	"ldq $27, 224($30)\n" //this was updated in the callback with the target

	"lda $30, 232($30)\n" //restore sp
	"jmp $31, ($27)\n" //jump to the new function
	".end AlphaCompilationCallback\n"
	);
	#else
	void AlphaCompilationCallback() {
	llvm_unreachable("Cannot call AlphaCompilationCallback() on a non-Alpha arch!");
	}
	#endif
	}

	TargetJITInfo::StubLayout AlphaJITInfo::getStubLayout() {
	// The stub contains 19 4-byte instructions, aligned at 4 bytes:
	// R0 = R27
	// 8 x "R27 <<= 8; R27 \|= 8-bits-of-Target" == 16 instructions
	// JMP R27
	// Magic number so the compilation callback can recognize the stub.
	StubLayout Result = {19 * 4, 4};
	return Result;
	}

	void AlphaJITInfo::emitFunctionStub(const Function F, void *Fn,
	JITCodeEmitter &JCE) {
	//assert(Fn == AlphaCompilationCallback && "Where are you going?\n");
	//Do things in a stupid slow way!
	void* Addr = (void*)(intptr_t)JCE.getCurrentPCValue();
	for (int x = 0; x < 19; ++ x)
	JCE.emitWordLE(0);
	EmitBranchToAt(Addr, Fn);
	DEBUG(errs() << "Emitting Stub to " << Fn << " at [" << Addr << "]\n");
	return Addr;
	}

	TargetJITInfo::LazyResolverFn
	AlphaJITInfo::getLazyResolverFunction(JITCompilerFn F) {
	JITCompilerFunction = F;
	// setZerothGOTEntry((void*)AlphaCompilationCallback);
	return AlphaCompilationCallback;
	}

	//These describe LDAx
	static const int IMM_LOW = -32768;
	static const int IMM_HIGH = 32767;
	static const int IMM_MULT = 65536;

	static long getUpper16(long l)
	{
	long y = l / IMM_MULT;
	if (l % IMM_MULT > IMM_HIGH)
	++y;
	if (l % IMM_MULT < IMM_LOW)
	--y;
	assert((short)y == y && "displacement out of range");
	return y;
	}

	static long getLower16(long l)
	{
	long h = getUpper16(l);
	long y = l - h * IMM_MULT;
	assert(y == (short)y && "Displacement out of range");
	return y;
	}

	void AlphaJITInfo::relocate(void Function, MachineRelocation MR,
	unsigned NumRelocs, unsigned char* GOTBase) {
	for (unsigned i = 0; i != NumRelocs; ++i, ++MR) {
	unsigned RelocPos = (unsigned)Function + MR->getMachineCodeOffset()/4;
	long idx = 0;
	bool doCommon = true;
	switch ((Alpha::RelocationType)MR->getRelocationType()) {
	default: llvm_unreachable("Unknown relocation type!");
	case Alpha::reloc_literal:
	//This is a LDQl
	idx = MR->getGOTIndex();
	DEBUG(errs() << "Literal relocation to slot " << idx);
	idx = (idx - GOToffset) * 8;
	DEBUG(errs() << " offset " << idx << "\n");
	break;
	case Alpha::reloc_gprellow:
	idx = (unsigned char)MR->getResultPointer() - &GOTBase[GOToffset 8];
	idx = getLower16(idx);
	DEBUG(errs() << "gprellow relocation offset " << idx << "\n");
	DEBUG(errs() << " Pointer is " << (void*)MR->getResultPointer()
	<< " GOT is " << (void)&GOTBase[GOToffset 8] << "\n");
	break;
	case Alpha::reloc_gprelhigh:
	idx = (unsigned char)MR->getResultPointer() - &GOTBase[GOToffset 8];
	idx = getUpper16(idx);
	DEBUG(errs() << "gprelhigh relocation offset " << idx << "\n");
	DEBUG(errs() << " Pointer is " << (void*)MR->getResultPointer()
	<< " GOT is " << (void)&GOTBase[GOToffset 8] << "\n");
	break;
	case Alpha::reloc_gpdist:
	switch (*RelocPos >> 26) {
	case 0x09: //LDAH
	idx = &GOTBase[GOToffset * 8] - (unsigned char*)RelocPos;
	idx = getUpper16(idx);
	DEBUG(errs() << "LDAH: " << idx << "\n");
	//add the relocation to the map
	gpdistmap[std::make_pair(Function, MR->getConstantVal())] = RelocPos;
	break;
	case 0x08: //LDA
	assert(gpdistmap[std::make_pair(Function, MR->getConstantVal())] &&
	"LDAg without seeing LDAHg");
	idx = &GOTBase[GOToffset * 8] -
	(unsigned char*)gpdistmap[std::make_pair(Function, MR->getConstantVal())];
	idx = getLower16(idx);
	DEBUG(errs() << "LDA: " << idx << "\n");
	break;
	default:
	llvm_unreachable("Cannot handle gpdist yet");
	}
	break;
	case Alpha::reloc_bsr: {
	idx = (((unsigned char*)MR->getResultPointer() -
	(unsigned char*)RelocPos) >> 2) + 1; //skip first 2 inst of fun
	*RelocPos \|= (idx & ((1 << 21)-1));
	doCommon = false;
	break;
	}
	}
	if (doCommon) {
	short x = (short)idx;
	assert(x == idx);
	(short)RelocPos = x;
	}
	}
	}