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"
22 static TargetJITInfo::JITCompilerFn JITCompilerFunction;
24 #define BUILD_ADDIS(RD,RS,IMM16) \
25 ((15 << 26) | ((RD) << 21) | ((RS) << 16) | ((IMM16) & 65535))
26 #define BUILD_ORI(RD,RS,UIMM16) \
27 ((24 << 26) | ((RS) << 21) | ((RD) << 16) | ((UIMM16) & 65535))
28 #define BUILD_MTSPR(RS,SPR) \
29 ((31 << 26) | ((RS) << 21) | ((SPR) << 16) | (467 << 1))
30 #define BUILD_BCCTRx(BO,BI,LINK) \
31 ((19 << 26) | ((BO) << 21) | ((BI) << 16) | (528 << 1) | ((LINK) & 1))
34 #define BUILD_LIS(RD,IMM16) BUILD_ADDIS(RD,0,IMM16)
35 #define BUILD_MTCTR(RS) BUILD_MTSPR(RS,9)
36 #define BUILD_BCTR(LINK) BUILD_BCCTRx(20,0,LINK)
39 static void EmitBranchToAt(void *At, void *To, bool isCall) {
40 intptr_t Addr = (intptr_t)To;
42 // FIXME: should special case the short branch case.
43 unsigned *AtI = (unsigned*)At;
45 AtI[0] = BUILD_LIS(12, Addr >> 16); // lis r12, hi16(address)
46 AtI[1] = BUILD_ORI(12, 12, Addr); // ori r12, r12, low16(address)
47 AtI[2] = BUILD_MTCTR(12); // mtctr r12
48 AtI[3] = BUILD_BCTR(isCall); // bctr/bctrl
51 extern "C" void PPC32CompilationCallback();
53 #if defined(__POWERPC__) || defined (__ppc__) || defined(_POWER)
54 // CompilationCallback stub - We can't use a C function with inline assembly in
55 // it, because we the prolog/epilog inserted by GCC won't work for us. Instead,
56 // write our own wrapper, which does things our way, so we have complete control
57 // over register saving and restoring.
61 ".globl _PPC32CompilationCallback\n"
62 "_PPC32CompilationCallback:\n"
63 // Make space for 29 ints r[3-31] and 14 doubles f[0-13]
66 "stw r11, 280(r1)\n" // Set up a proper stack frame
67 "stmw r3, 156(r1)\n" // Save all of the integer registers
68 // Save all call-clobbered FP regs.
69 "stfd f1, 44(r1)\n" "stfd f2, 52(r1)\n" "stfd f3, 60(r1)\n"
70 "stfd f4, 68(r1)\n" "stfd f5, 76(r1)\n" "stfd f6, 84(r1)\n"
71 "stfd f7, 92(r1)\n" "stfd f8, 100(r1)\n" "stfd f9, 108(r1)\n"
72 "stfd f10, 116(r1)\n" "stfd f11, 124(r1)\n" "stfd f12, 132(r1)\n"
75 // Now that everything is saved, go to the C compilation callback function,
76 // passing the address of the intregs and fpregs.
77 "addi r3, r1, 156\n" // &IntRegs[0]
78 "addi r4, r1, 44\n" // &FPRegs[0]
79 "bl _PPC32CompilationCallbackC\n"
83 extern "C" void PPC32CompilationCallbackC(unsigned *IntRegs, double *FPRegs) {
84 unsigned *CameFromStub = (unsigned*)__builtin_return_address(0+1);
85 unsigned *CameFromOrig = (unsigned*)__builtin_return_address(1+1);
86 unsigned *CCStackPtr = (unsigned*)__builtin_frame_address(0);
87 //unsigned *StubStackPtr = (unsigned*)__builtin_frame_address(1);
88 unsigned *OrigStackPtr = (unsigned*)__builtin_frame_address(2+1);
90 // Adjust pointer to the branch, not the return address.
93 void *Target = JITCompilerFunction(CameFromStub);
95 // Check to see if CameFromOrig[-1] is a 'bl' instruction, and if we can
96 // rewrite it to branch directly to the destination. If so, rewrite it so it
97 // does not need to go through the stub anymore.
98 unsigned CameFromOrigInst = CameFromOrig[-1];
99 if ((CameFromOrigInst >> 26) == 18) { // Direct call.
100 intptr_t Offset = ((intptr_t)Target-(intptr_t)CameFromOrig+4) >> 2;
101 if (Offset >= -(1 << 23) && Offset < (1 << 23)) { // In range?
102 // Clear the original target out.
103 CameFromOrigInst &= (63 << 26) | 3;
104 // Fill in the new target.
105 CameFromOrigInst |= (Offset & ((1 << 24)-1)) << 2;
107 CameFromOrig[-1] = CameFromOrigInst;
111 // Locate the start of the stub. If this is a short call, adjust backwards
112 // the short amount, otherwise the full amount.
113 bool isShortStub = (*CameFromStub >> 26) == 18;
114 CameFromStub -= isShortStub ? 2 : 6;
116 // Rewrite the stub with an unconditional branch to the target, for any users
117 // who took the address of the stub.
118 EmitBranchToAt(CameFromStub, Target, false);
120 // Change the SP so that we pop two stack frames off when we return.
121 *CCStackPtr = (intptr_t)OrigStackPtr;
123 // Put the address of the stub and the LR value that originally came into the
124 // stub in a place that is easy to get on the stack after we restore all regs.
125 CCStackPtr[2] = (intptr_t)Target;
126 CCStackPtr[1] = (intptr_t)CameFromOrig;
128 // Note, this is not a standard epilog!
129 #if defined(__POWERPC__) || defined (__ppc__) || defined(_POWER)
130 register unsigned *IRR asm ("r2") = IntRegs;
131 register double *FRR asm ("r3") = FPRegs;
132 __asm__ __volatile__ (
133 "lfd f1, 0(%0)\n" "lfd f2, 8(%0)\n" "lfd f3, 16(%0)\n"
134 "lfd f4, 24(%0)\n" "lfd f5, 32(%0)\n" "lfd f6, 40(%0)\n"
135 "lfd f7, 48(%0)\n" "lfd f8, 56(%0)\n" "lfd f9, 64(%0)\n"
136 "lfd f10, 72(%0)\n" "lfd f11, 80(%0)\n" "lfd f12, 88(%0)\n"
138 "lmw r3, 0(%1)\n" // Load all integer regs
139 "lwz r0,4(r1)\n" // Get CameFromOrig (LR into stub)
140 "mtlr r0\n" // Put it in the LR register
141 "lwz r0,8(r1)\n" // Get target function pointer
142 "mtctr r0\n" // Put it into the CTR register
143 "lwz r1,0(r1)\n" // Pop two frames off
144 "bctr\n" :: // Return to stub!
145 "b" (FRR), "b" (IRR));
151 TargetJITInfo::LazyResolverFn
152 PPC32JITInfo::getLazyResolverFunction(JITCompilerFn Fn) {
153 JITCompilerFunction = Fn;
154 return PPC32CompilationCallback;
157 void *PPC32JITInfo::emitFunctionStub(void *Fn, MachineCodeEmitter &MCE) {
158 // If this is just a call to an external function, emit a branch instead of a
159 // call. The code is the same except for one bit of the last instruction.
160 if (Fn != PPC32CompilationCallback) {
161 MCE.startFunctionStub(4*4);
162 void *Addr = (void*)(intptr_t)MCE.getCurrentPCValue();
167 EmitBranchToAt(Addr, Fn, false);
168 return MCE.finishFunctionStub(0);
171 MCE.startFunctionStub(4*7);
172 MCE.emitWord(0x9421ffe0); // stwu r1,-32(r1)
173 MCE.emitWord(0x7d6802a6); // mflr r11
174 MCE.emitWord(0x91610028); // stw r11, 40(r1)
175 void *Addr = (void*)(intptr_t)MCE.getCurrentPCValue();
180 EmitBranchToAt(Addr, Fn, true/*is call*/);
181 return MCE.finishFunctionStub(0);
185 void PPC32JITInfo::relocate(void *Function, MachineRelocation *MR,
186 unsigned NumRelocs) {
187 for (unsigned i = 0; i != NumRelocs; ++i, ++MR) {
188 unsigned *RelocPos = (unsigned*)Function + MR->getMachineCodeOffset()/4;
189 intptr_t ResultPtr = (intptr_t)MR->getResultPointer();
190 switch ((PPC::RelocationType)MR->getRelocationType()) {
191 default: assert(0 && "Unknown relocation type!");
192 case PPC::reloc_pcrel_bx:
193 // PC-relative relocation for b and bl instructions.
194 ResultPtr = (ResultPtr-(intptr_t)RelocPos) >> 2;
195 assert(ResultPtr >= -(1 << 23) && ResultPtr < (1 << 23) &&
196 "Relocation out of range!");
197 *RelocPos |= (ResultPtr & ((1 << 24)-1)) << 2;
200 case PPC::reloc_absolute_ptr_high: // Pointer relocations.
201 case PPC::reloc_absolute_ptr_low: {
202 // Pointer relocations are used for the PPC external stubs and lazy
203 // resolver pointers that the Darwin ABI likes to use. Basically, the
204 // address of the global is actually stored in memory, and the address of
205 // the pointer is relocated into instructions instead of the pointer
206 // itself. Because we have to keep the mapping anyway, we just return
207 // pointers to the values in the map as our new location.
208 static std::map<void*,void*> Pointers;
209 void *&Ptr = Pointers[(void*)ResultPtr];
210 Ptr = (void*)ResultPtr;
211 ResultPtr = (intptr_t)&Ptr;
214 case PPC::reloc_absolute_high: // high bits of ref -> low 16 of instr
215 case PPC::reloc_absolute_low: // low bits of ref -> low 16 of instr
216 ResultPtr += MR->getConstantVal();
218 // If this is a high-part access, get the high-part.
219 if (MR->getRelocationType() == PPC::reloc_absolute_high ||
220 MR->getRelocationType() == PPC::reloc_absolute_ptr_high) {
221 // If the low part will have a carry (really a borrow) from the low
222 // 16-bits into the high 16, add a bit to borrow from.
223 if (((int)ResultPtr << 16) < 0)
224 ResultPtr += 1 << 16;
228 // Do the addition then mask, so the addition does not overflow the 16-bit
229 // immediate section of the instruction.
230 unsigned LowBits = (*RelocPos + ResultPtr) & 65535;
231 unsigned HighBits = *RelocPos & ~65535;
232 *RelocPos = LowBits | HighBits; // Slam into low 16-bits
238 void PPC32JITInfo::replaceMachineCodeForFunction(void *Old, void *New) {
239 EmitBranchToAt(Old, New, false);