1 //===-- PPC32JITInfo.cpp - Implement the JIT interfaces for the PowerPC ---===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by the LLVM research group and is distributed under
6 // the University of Illinois Open Source License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements the JIT interfaces for the 32-bit PowerPC target.
12 //===----------------------------------------------------------------------===//
14 #define DEBUG_TYPE "jit"
15 #include "PPC32JITInfo.h"
16 #include "PPC32Relocations.h"
17 #include "llvm/CodeGen/MachineCodeEmitter.h"
18 #include "llvm/Config/alloca.h"
21 static TargetJITInfo::JITCompilerFn JITCompilerFunction;
23 #define BUILD_ADDIS(RD,RS,IMM16) \
24 ((15 << 26) | ((RD) << 21) | ((RS) << 16) | ((IMM16) & 65535))
25 #define BUILD_ORI(RD,RS,UIMM16) \
26 ((24 << 26) | ((RS) << 21) | ((RD) << 16) | ((UIMM16) & 65535))
27 #define BUILD_MTSPR(RS,SPR) \
28 ((31 << 26) | ((RS) << 21) | ((SPR) << 16) | (467 << 1))
29 #define BUILD_BCCTRx(BO,BI,LINK) \
30 ((19 << 26) | ((BO) << 21) | ((BI) << 16) | (528 << 1) | ((LINK) & 1))
33 #define BUILD_LIS(RD,IMM16) BUILD_ADDIS(RD,0,IMM16)
34 #define BUILD_MTCTR(RS) BUILD_MTSPR(RS,9)
35 #define BUILD_BCTR(LINK) BUILD_BCCTRx(20,0,LINK)
38 static void EmitBranchToAt(void *At, void *To, bool isCall) {
39 intptr_t Addr = (intptr_t)To;
41 // FIXME: should special case the short branch case.
42 unsigned *AtI = (unsigned*)At;
44 AtI[0] = BUILD_LIS(12, Addr >> 16); // lis r12, hi16(address)
45 AtI[1] = BUILD_ORI(12, 12, Addr); // ori r12, r12, low16(address)
46 AtI[2] = BUILD_MTCTR(12); // mtctr r12
47 AtI[3] = BUILD_BCTR(isCall); // bctr/bctrl
50 static void CompilationCallback() {
51 // Save R3-R31, since we want to restore arguments and nonvolatile regs used
52 // by the compiler. We also save and restore the FP regs, although this is
53 // probably just paranoia (gcc is unlikely to emit code that uses them for
55 #if defined(__POWERPC__) || defined (__ppc__) || defined(_POWER)
58 __asm__ __volatile__ (
60 "stfd f1, 0(%1)\n" "stfd f2, 8(%1)\n" "stfd f3, 16(%1)\n"
61 "stfd f4, 24(%1)\n" "stfd f5, 32(%1)\n" "stfd f6, 40(%1)\n"
62 "stfd f7, 48(%1)\n" "stfd f8, 56(%1)\n" "stfd f9, 64(%1)\n"
63 "stfd f10, 72(%1)\n" "stfd f11, 80(%1)\n" "stfd f12, 88(%1)\n"
64 "stfd f13, 96(%1)\n" :: "b" (IntRegs), "b" (FPRegs) );
65 /// FIXME: Need to safe and restore the rest of the FP regs!
68 unsigned *CameFromStub = (unsigned*)__builtin_return_address(0);
69 unsigned *CameFromOrig = (unsigned*)__builtin_return_address(1);
70 unsigned *CCStackPtr = (unsigned*)__builtin_frame_address(0);
71 //unsigned *StubStackPtr = (unsigned*)__builtin_frame_address(1);
72 unsigned *OrigStackPtr = (unsigned*)__builtin_frame_address(2);
74 // Adjust pointer to the branch, not the return address.
77 void *Target = JITCompilerFunction(CameFromStub);
79 // Check to see if CameFromOrig[-1] is a 'bl' instruction, and if we can
80 // rewrite it to branch directly to the destination. If so, rewrite it so it
81 // does not need to go through the stub anymore.
82 unsigned CameFromOrigInst = CameFromOrig[-1];
83 if ((CameFromOrigInst >> 26) == 18) { // Direct call.
84 intptr_t Offset = ((intptr_t)Target-(intptr_t)CameFromOrig+4) >> 2;
85 if (Offset >= -(1 << 23) && Offset < (1 << 23)) { // In range?
86 // Clear the original target out.
87 CameFromOrigInst &= (63 << 26) | 3;
88 // Fill in the new target.
89 CameFromOrigInst |= (Offset & ((1 << 24)-1)) << 2;
91 CameFromOrig[-1] = CameFromOrigInst;
95 // Locate the start of the stub. If this is a short call, adjust backwards
96 // the short amount, otherwise the full amount.
97 bool isShortStub = (*CameFromStub >> 26) == 18;
98 CameFromStub -= isShortStub ? 2 : 6;
100 // Rewrite the stub with an unconditional branch to the target, for any users
101 // who took the address of the stub.
102 EmitBranchToAt(CameFromStub, Target, false);
104 // Change the SP so that we pop two stack frames off when we return.
105 *CCStackPtr = (intptr_t)OrigStackPtr;
107 // Put the address of the stub and the LR value that originally came into the
108 // stub in a place that is easy to get on the stack after we restore all regs.
109 CCStackPtr[2] = (intptr_t)Target;
110 CCStackPtr[1] = (intptr_t)CameFromOrig;
112 // Note, this is not a standard epilog!
113 #if defined(__POWERPC__) || defined (__ppc__) || defined(_POWER)
114 register unsigned *IRR asm ("r2") = IntRegs;
115 register double *FRR asm ("r3") = FPRegs;
116 __asm__ __volatile__ (
117 "lfd f1, 0(%0)\n" "lfd f2, 8(%0)\n" "lfd f3, 16(%0)\n"
118 "lfd f4, 24(%0)\n" "lfd f5, 32(%0)\n" "lfd f6, 40(%0)\n"
119 "lfd f7, 48(%0)\n" "lfd f8, 56(%0)\n" "lfd f9, 64(%0)\n"
120 "lfd f10, 72(%0)\n" "lfd f11, 80(%0)\n" "lfd f12, 88(%0)\n"
122 "lmw r3, 0(%1)\n" // Load all integer regs
123 "lwz r0,4(r1)\n" // Get CameFromOrig (LR into stub)
124 "mtlr r0\n" // Put it in the LR register
125 "lwz r0,8(r1)\n" // Get target function pointer
126 "mtctr r0\n" // Put it into the CTR register
127 "lwz r1,0(r1)\n" // Pop two frames off
128 "bctr\n" :: // Return to stub!
129 "b" (FRR), "b" (IRR));
135 TargetJITInfo::LazyResolverFn
136 PPC32JITInfo::getLazyResolverFunction(JITCompilerFn Fn) {
137 JITCompilerFunction = Fn;
138 return CompilationCallback;
141 void *PPC32JITInfo::emitFunctionStub(void *Fn, MachineCodeEmitter &MCE) {
142 // If this is just a call to an external function, emit a branch instead of a
143 // call. The code is the same except for one bit of the last instruction.
144 if (Fn != CompilationCallback) {
145 MCE.startFunctionStub(4*4);
146 void *Addr = (void*)(intptr_t)MCE.getCurrentPCValue();
151 EmitBranchToAt(Addr, Fn, false);
152 return MCE.finishFunctionStub(0);
155 MCE.startFunctionStub(4*7);
156 MCE.emitWord(0x9421ffe0); // stwu r1,-32(r1)
157 MCE.emitWord(0x7d6802a6); // mflr r11
158 MCE.emitWord(0x91610028); // stw r11, 40(r1)
159 void *Addr = (void*)(intptr_t)MCE.getCurrentPCValue();
164 EmitBranchToAt(Addr, Fn, true/*is call*/);
165 return MCE.finishFunctionStub(0);
169 void PPC32JITInfo::relocate(void *Function, MachineRelocation *MR,
170 unsigned NumRelocs) {
171 for (unsigned i = 0; i != NumRelocs; ++i, ++MR) {
172 unsigned *RelocPos = (unsigned*)Function + MR->getMachineCodeOffset()/4;
173 intptr_t ResultPtr = (intptr_t)MR->getResultPointer();
174 switch ((PPC::RelocationType)MR->getRelocationType()) {
175 default: assert(0 && "Unknown relocation type!");
176 case PPC::reloc_pcrel_bx:
177 // PC-relative relocation for b and bl instructions.
178 ResultPtr = (ResultPtr-(intptr_t)RelocPos) >> 2;
179 assert(ResultPtr >= -(1 << 23) && ResultPtr < (1 << 23) &&
180 "Relocation out of range!");
181 *RelocPos |= (ResultPtr & ((1 << 24)-1)) << 2;
183 case PPC::reloc_absolute_loadhi: // Relocate high bits into addis
184 case PPC::reloc_absolute_la: // Relocate low bits into addi
185 ResultPtr += MR->getConstantVal();
187 if (MR->getRelocationType() == PPC::reloc_absolute_loadhi) {
188 // If the low part will have a carry (really a borrow) from the low
189 // 16-bits into the high 16, add a bit to borrow from.
190 if (((int)ResultPtr << 16) < 0)
191 ResultPtr += 1 << 16;
195 // Do the addition then mask, so the addition does not overflow the 16-bit
196 // immediate section of the instruction.
197 unsigned LowBits = (*RelocPos + ResultPtr) & 65535;
198 unsigned HighBits = *RelocPos & ~65535;
199 *RelocPos = LowBits | HighBits; // Slam into low 16-bits
205 void PPC32JITInfo::replaceMachineCodeForFunction(void *Old, void *New) {
206 EmitBranchToAt(Old, New, false);