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 // FIXME: Should save R3-R10 and F1-F13 onto the stack, just like the Sparc
54 //uint64_t FPRegs[13];
55 unsigned *CameFromStub = (unsigned*)__builtin_return_address(0);
56 unsigned *CameFromOrig = (unsigned*)__builtin_return_address(1);
57 unsigned *CCStackPtr = (unsigned*)__builtin_frame_address(0);
58 //unsigned *StubStackPtr = (unsigned*)__builtin_frame_address(1);
59 unsigned *OrigStackPtr = (unsigned*)__builtin_frame_address(2);
61 // Adjust pointer to the branch, not the return address.
64 void *Target = JITCompilerFunction(CameFromStub);
66 // Check to see if CameFromOrig[-1] is a 'bl' instruction, and if we can
67 // rewrite it to branch directly to the destination. If so, rewrite it so it
68 // does not need to go through the stub anymore.
69 unsigned CameFromOrigInst = CameFromOrig[-1];
70 if ((CameFromOrigInst >> 26) == 18) { // Direct call.
71 intptr_t Offset = ((intptr_t)Target-(intptr_t)CameFromOrig) >> 2;
72 if (Offset >= -(1 << 23) && Offset < (1 << 23)) { // In range?
73 // FIXME: hasn't been tested at all.
74 // Clear the original target out:
75 CameFromOrigInst &= (63 << 26) | 3;
76 CameFromOrigInst |= Offset << 2;
77 CameFromOrig[-1] = CameFromOrigInst;
81 // Locate the start of the stub. If this is a short call, adjust backwards
82 // the short amount, otherwise the full amount.
83 bool isShortStub = (*CameFromStub >> 26) == 18;
84 CameFromStub -= isShortStub ? 2 : 6;
86 // Rewrite the stub with an unconditional branch to the target, for any users
87 // who took the address of the stub.
88 EmitBranchToAt(CameFromStub, Target, false);
90 // Change the SP so that we pop two stack frames off when we return.
91 *CCStackPtr = (intptr_t)OrigStackPtr;
93 // Put the address of the stub and the LR value that originally came into the
94 // stub in a place that is easy to get on the stack after we restore all regs.
95 CCStackPtr[2] = (intptr_t)CameFromStub;
96 CCStackPtr[1] = (intptr_t)CameFromOrig;
98 // FIXME: Need to restore the registers from IntRegs/FPRegs.
100 // Note, this is not a standard epilog!
101 #if defined(__POWERPC__) || defined (__ppc__) || defined(_POWER)
102 __asm__ __volatile__ ("lwz r0,4(r1)\n" // Get CameFromOrig (LR into stub)
103 "mtlr r0\n" // Put it in the LR register
104 "lwz r0,8(r1)\n" // Get "CameFromStub"
105 "mtctr r0\n" // Put it into the CTR register
106 "lwz r1,0(r1)\n" // Pop two frames off
107 "bctr\n" ::); // Return to stub!
113 TargetJITInfo::LazyResolverFn
114 PPC32JITInfo::getLazyResolverFunction(JITCompilerFn Fn) {
115 JITCompilerFunction = Fn;
116 return CompilationCallback;
119 void *PPC32JITInfo::emitFunctionStub(void *Fn, MachineCodeEmitter &MCE) {
120 // If this is just a call to an external function, emit a branch instead of a
121 // call. The code is the same except for one bit of the last instruction.
122 if (Fn != CompilationCallback) {
123 MCE.startFunctionStub(4*4);
124 void *Addr = (void*)(intptr_t)MCE.getCurrentPCValue();
129 EmitBranchToAt(Addr, Fn, false);
130 return MCE.finishFunctionStub(0);
133 MCE.startFunctionStub(4*7);
134 MCE.emitWord(0x9421ffe0); // stwu r1,-32(r1)
135 MCE.emitWord(0x7d6802a6); // mflr r11
136 MCE.emitWord(0x91610028); // stw r11, 40(r1)
137 void *Addr = (void*)(intptr_t)MCE.getCurrentPCValue();
142 EmitBranchToAt(Addr, Fn, true/*is call*/);
143 return MCE.finishFunctionStub(0);
147 void PPC32JITInfo::relocate(void *Function, MachineRelocation *MR,
148 unsigned NumRelocs) {
149 for (unsigned i = 0; i != NumRelocs; ++i, ++MR) {
150 unsigned *RelocPos = (unsigned*)Function + MR->getMachineCodeOffset()/4;
151 intptr_t ResultPtr = (intptr_t)MR->getResultPointer();
152 switch ((PPC::RelocationType)MR->getRelocationType()) {
153 default: assert(0 && "Unknown relocation type!");
154 case PPC::reloc_pcrel_bx:
155 // PC-relative relocation for b and bl instructions.
156 ResultPtr = (ResultPtr-(intptr_t)RelocPos) >> 2;
157 assert(ResultPtr >= -(1 << 23) && ResultPtr < (1 << 23) &&
158 "Relocation out of range!");
159 *RelocPos |= (ResultPtr & ((1 << 24)-1)) << 2;
161 case PPC::reloc_absolute_loadhi: // Relocate high bits into addis
162 case PPC::reloc_absolute_la: // Relocate low bits into addi
163 ResultPtr += MR->getConstantVal();
165 if (MR->getRelocationType() == PPC::reloc_absolute_loadhi) {
166 // If the low part will have a carry (really a borrow) from the low
167 // 16-bits into the high 16, add a bit to borrow from.
168 if (((int)ResultPtr << 16) < 0)
169 ResultPtr += 1 << 16;
173 // Do the addition then mask, so the addition does not overflow the 16-bit
174 // immediate section of the instruction.
175 unsigned LowBits = (*RelocPos + ResultPtr) & 65535;
176 unsigned HighBits = *RelocPos & ~65535;
177 *RelocPos = LowBits | HighBits; // Slam into low 16-bits
183 void PPC32JITInfo::replaceMachineCodeForFunction(void *Old, void *New) {
184 EmitBranchToAt(Old, New, false);