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Preliminary support for X86-64 JIT stub codegen.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@35095 91177308-0d34-0410-b5e6-96231b3b80d8
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@ -205,9 +205,9 @@ extern "C" {
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#ifdef _MSC_VER
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extern "C" void X86CompilationCallback2() {
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assert(sizeof(size_t) == 4); // FIXME: handle Win64
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unsigned *RetAddrLoc = (unsigned *)_AddressOfReturnAddress();
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intptr_t *RetAddrLoc = (intptr_t *)_AddressOfReturnAddress();
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RetAddrLoc += 4; // skip over ret addr, edx, eax, ecx
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unsigned RetAddr = *RetAddrLoc;
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intptr_t RetAddr = *RetAddrLoc;
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#else
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extern "C" void X86CompilationCallback2(intptr_t *StackPtr, intptr_t RetAddr) {
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intptr_t *RetAddrLoc = &StackPtr[1];
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@ -219,7 +219,11 @@ extern "C" void X86CompilationCallback2(intptr_t *StackPtr, intptr_t RetAddr) {
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bool isStub = ((unsigned char*)RetAddr)[0] == 0xCD;
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// The call instruction should have pushed the return value onto the stack...
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#ifdef __x86_64__
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RetAddr--; // Backtrack to the reference itself...
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#else
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RetAddr -= 4; // Backtrack to the reference itself...
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#endif
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#if 0
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DOUT << "In callback! Addr=" << (void*)RetAddr
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@ -229,24 +233,41 @@ extern "C" void X86CompilationCallback2(intptr_t *StackPtr, intptr_t RetAddr) {
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#endif
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// Sanity check to make sure this really is a call instruction.
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#ifdef __x86_64__
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assert(((unsigned char*)RetAddr)[-2] == 0x41 &&"Not a call instr!");
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assert(((unsigned char*)RetAddr)[-1] == 0xFF &&"Not a call instr!");
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#else
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assert(((unsigned char*)RetAddr)[-1] == 0xE8 &&"Not a call instr!");
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#endif
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intptr_t NewVal = (intptr_t)JITCompilerFunction((void*)RetAddr);
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// Rewrite the call target... so that we don't end up here every time we
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// execute the call.
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*(unsigned *)RetAddr = (unsigned)(NewVal-RetAddr-4);
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#ifdef __x86_64__
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*(intptr_t *)(RetAddr - 0xa) = NewVal;
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#else
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*(intptr_t *)RetAddr = (intptr_t)(NewVal-RetAddr-4);
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#endif
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if (isStub) {
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// If this is a stub, rewrite the call into an unconditional branch
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// instruction so that two return addresses are not pushed onto the stack
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// when the requested function finally gets called. This also makes the
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// 0xCD byte (interrupt) dead, so the marker doesn't effect anything.
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#ifdef __x86_64__
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((unsigned char*)RetAddr)[0] = (2 | (4 << 3) | (3 << 6));
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#else
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((unsigned char*)RetAddr)[-1] = 0xE9;
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#endif
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}
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// Change the return address to reexecute the call instruction...
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#ifdef __x86_64__
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*RetAddrLoc -= 0xd;
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#else
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*RetAddrLoc -= 5;
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#endif
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}
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TargetJITInfo::LazyResolverFn
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@ -291,10 +312,21 @@ void *X86JITInfo::emitFunctionStub(void *Fn, MachineCodeEmitter &MCE) {
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return MCE.finishFunctionStub(0);
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}
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#ifdef __x86_64__
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MCE.startFunctionStub(14, 4);
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MCE.emitByte(0x49); // REX prefix
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MCE.emitByte(0xB8+2); // movabsq r10
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MCE.emitWordLE(((unsigned *)&Fn)[0]);
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MCE.emitWordLE(((unsigned *)&Fn)[1]);
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MCE.emitByte(0x41); // REX prefix
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MCE.emitByte(0xFF); // callq *r10
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MCE.emitByte(2 | (2 << 3) | (3 << 6));
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#else
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MCE.startFunctionStub(6, 4);
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MCE.emitByte(0xE8); // Call with 32 bit pc-rel destination...
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MCE.emitWordLE((intptr_t)Fn-MCE.getCurrentPCValue()-4);
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#endif
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MCE.emitByte(0xCD); // Interrupt - Just a marker identifying the stub!
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return MCE.finishFunctionStub(0);
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