//===-- PPC32JITInfo.cpp - Implement the JIT interfaces for the PowerPC ---===// // // The LLVM Compiler Infrastructure // // This file was developed by the LLVM research group and is distributed under // the University of Illinois Open Source License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // // This file implements the JIT interfaces for the 32-bit PowerPC target. // //===----------------------------------------------------------------------===// #define DEBUG_TYPE "jit" #include "PPC32JITInfo.h" #include "PPC32Relocations.h" #include "llvm/CodeGen/MachineCodeEmitter.h" #include "llvm/Config/alloca.h" using namespace llvm; static TargetJITInfo::JITCompilerFn JITCompilerFunction; #define BUILD_ADDIS(RD,RS,IMM16) \ ((15 << 26) | ((RD) << 21) | ((RS) << 16) | ((IMM16) & 65535)) #define BUILD_ORI(RD,RS,UIMM16) \ ((24 << 26) | ((RS) << 21) | ((RD) << 16) | ((UIMM16) & 65535)) #define BUILD_MTSPR(RS,SPR) \ ((31 << 26) | ((RS) << 21) | ((SPR) << 16) | (467 << 1)) #define BUILD_BCCTRx(BO,BI,LINK) \ ((19 << 26) | ((BO) << 21) | ((BI) << 16) | (528 << 1) | ((LINK) & 1)) // Pseudo-ops #define BUILD_LIS(RD,IMM16) BUILD_ADDIS(RD,0,IMM16) #define BUILD_MTCTR(RS) BUILD_MTSPR(RS,9) #define BUILD_BCTR(LINK) BUILD_BCCTRx(20,0,LINK) static void EmitBranchToAt(void *At, void *To, bool isCall) { intptr_t Addr = (intptr_t)To; // FIXME: should special case the short branch case. unsigned *AtI = (unsigned*)At; AtI[0] = BUILD_LIS(12, Addr >> 16); // lis r12, hi16(address) AtI[1] = BUILD_ORI(12, 12, Addr); // ori r12, r12, low16(address) AtI[2] = BUILD_MTCTR(12); // mtctr r12 AtI[3] = BUILD_BCTR(isCall); // bctr/bctrl } static void CompilationCallback() { // Save R3-R31, since we want to restore arguments and nonvolatile regs used // by the compiler. We also save and restore the FP regs, although this is // probably just paranoia (gcc is unlikely to emit code that uses them for // for this function. #if defined(__POWERPC__) || defined (__ppc__) || defined(_POWER) unsigned IntRegs[29]; double FPRegs[13]; __asm__ __volatile__ ( "stmw r3, 0(%0)\n" "stfd f1, 0(%1)\n" "stfd f2, 8(%1)\n" "stfd f3, 16(%1)\n" "stfd f4, 24(%1)\n" "stfd f5, 32(%1)\n" "stfd f6, 40(%1)\n" "stfd f7, 48(%1)\n" "stfd f8, 56(%1)\n" "stfd f9, 64(%1)\n" "stfd f10, 72(%1)\n" "stfd f11, 80(%1)\n" "stfd f12, 88(%1)\n" "stfd f13, 96(%1)\n" :: "b" (IntRegs), "b" (FPRegs) ); #endif unsigned *CameFromStub = (unsigned*)__builtin_return_address(0); unsigned *CameFromOrig = (unsigned*)__builtin_return_address(1); unsigned *CCStackPtr = (unsigned*)__builtin_frame_address(0); //unsigned *StubStackPtr = (unsigned*)__builtin_frame_address(1); unsigned *OrigStackPtr = (unsigned*)__builtin_frame_address(2); // Adjust pointer to the branch, not the return address. --CameFromStub; void *Target = JITCompilerFunction(CameFromStub); // Check to see if CameFromOrig[-1] is a 'bl' instruction, and if we can // rewrite it to branch directly to the destination. If so, rewrite it so it // does not need to go through the stub anymore. unsigned CameFromOrigInst = CameFromOrig[-1]; if ((CameFromOrigInst >> 26) == 18) { // Direct call. intptr_t Offset = ((intptr_t)Target-(intptr_t)CameFromOrig) >> 2; if (Offset >= -(1 << 23) && Offset < (1 << 23)) { // In range? // FIXME: hasn't been tested at all. // Clear the original target out: CameFromOrigInst &= (63 << 26) | 3; CameFromOrigInst |= Offset << 2; CameFromOrig[-1] = CameFromOrigInst; } } // Locate the start of the stub. If this is a short call, adjust backwards // the short amount, otherwise the full amount. bool isShortStub = (*CameFromStub >> 26) == 18; CameFromStub -= isShortStub ? 2 : 6; // Rewrite the stub with an unconditional branch to the target, for any users // who took the address of the stub. EmitBranchToAt(CameFromStub, Target, false); // Change the SP so that we pop two stack frames off when we return. *CCStackPtr = (intptr_t)OrigStackPtr; // Put the address of the stub and the LR value that originally came into the // stub in a place that is easy to get on the stack after we restore all regs. CCStackPtr[2] = (intptr_t)CameFromStub; CCStackPtr[1] = (intptr_t)CameFromOrig; // Note, this is not a standard epilog! #if defined(__POWERPC__) || defined (__ppc__) || defined(_POWER) __asm__ __volatile__ ( "lfd f1, 0(%0)\n" "lfd f2, 8(%0)\n" "lfd f3, 16(%0)\n" "lfd f4, 24(%0)\n" "lfd f5, 32(%0)\n" "lfd f6, 40(%0)\n" "lfd f7, 48(%0)\n" "lfd f8, 56(%0)\n" "lfd f9, 64(%0)\n" "lfd f10, 72(%0)\n" "lfd f11, 80(%0)\n" "lfd f12, 88(%0)\n" "lfd f13, 96(%0)\n" "lmw r3, 0(%1)\n" "lwz r0,4(r1)\n" // Get CameFromOrig (LR into stub) "mtlr r0\n" // Put it in the LR register "lwz r0,8(r1)\n" // Get "CameFromStub" "mtctr r0\n" // Put it into the CTR register "lwz r1,0(r1)\n" // Pop two frames off "bctr\n" :: // Return to stub! "b" (FPRegs), "b" (IntRegs)); #endif } TargetJITInfo::LazyResolverFn PPC32JITInfo::getLazyResolverFunction(JITCompilerFn Fn) { JITCompilerFunction = Fn; return CompilationCallback; } void *PPC32JITInfo::emitFunctionStub(void *Fn, MachineCodeEmitter &MCE) { // If this is just a call to an external function, emit a branch instead of a // call. The code is the same except for one bit of the last instruction. if (Fn != CompilationCallback) { MCE.startFunctionStub(4*4); void *Addr = (void*)(intptr_t)MCE.getCurrentPCValue(); MCE.emitWord(0); MCE.emitWord(0); MCE.emitWord(0); MCE.emitWord(0); EmitBranchToAt(Addr, Fn, false); return MCE.finishFunctionStub(0); } MCE.startFunctionStub(4*7); MCE.emitWord(0x9421ffe0); // stwu r1,-32(r1) MCE.emitWord(0x7d6802a6); // mflr r11 MCE.emitWord(0x91610028); // stw r11, 40(r1) void *Addr = (void*)(intptr_t)MCE.getCurrentPCValue(); MCE.emitWord(0); MCE.emitWord(0); MCE.emitWord(0); MCE.emitWord(0); EmitBranchToAt(Addr, Fn, true/*is call*/); return MCE.finishFunctionStub(0); } void PPC32JITInfo::relocate(void *Function, MachineRelocation *MR, unsigned NumRelocs) { for (unsigned i = 0; i != NumRelocs; ++i, ++MR) { unsigned *RelocPos = (unsigned*)Function + MR->getMachineCodeOffset()/4; intptr_t ResultPtr = (intptr_t)MR->getResultPointer(); switch ((PPC::RelocationType)MR->getRelocationType()) { default: assert(0 && "Unknown relocation type!"); case PPC::reloc_pcrel_bx: // PC-relative relocation for b and bl instructions. ResultPtr = (ResultPtr-(intptr_t)RelocPos) >> 2; assert(ResultPtr >= -(1 << 23) && ResultPtr < (1 << 23) && "Relocation out of range!"); *RelocPos |= (ResultPtr & ((1 << 24)-1)) << 2; break; case PPC::reloc_absolute_loadhi: // Relocate high bits into addis case PPC::reloc_absolute_la: // Relocate low bits into addi ResultPtr += MR->getConstantVal(); if (MR->getRelocationType() == PPC::reloc_absolute_loadhi) { // If the low part will have a carry (really a borrow) from the low // 16-bits into the high 16, add a bit to borrow from. if (((int)ResultPtr << 16) < 0) ResultPtr += 1 << 16; ResultPtr >>= 16; } // Do the addition then mask, so the addition does not overflow the 16-bit // immediate section of the instruction. unsigned LowBits = (*RelocPos + ResultPtr) & 65535; unsigned HighBits = *RelocPos & ~65535; *RelocPos = LowBits | HighBits; // Slam into low 16-bits break; } } } void PPC32JITInfo::replaceMachineCodeForFunction(void *Old, void *New) { EmitBranchToAt(Old, New, false); }