1 //===-- X86JITInfo.cpp - Implement the JIT interfaces for the X86 target --===//
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 X86 target.
12 //===----------------------------------------------------------------------===//
14 #define DEBUG_TYPE "jit"
15 #include "X86JITInfo.h"
16 #include "X86Relocations.h"
17 #include "X86Subtarget.h"
18 #include "llvm/CodeGen/MachineCodeEmitter.h"
19 #include "llvm/Config/alloca.h"
25 extern "C" void *_AddressOfReturnAddress(void);
26 #pragma intrinsic(_AddressOfReturnAddress)
29 void X86JITInfo::replaceMachineCodeForFunction(void *Old, void *New) {
30 unsigned char *OldByte = (unsigned char *)Old;
31 *OldByte++ = 0xE9; // Emit JMP opcode.
32 unsigned *OldWord = (unsigned *)OldByte;
33 unsigned NewAddr = (intptr_t)New;
34 unsigned OldAddr = (intptr_t)OldWord;
35 *OldWord = NewAddr - OldAddr - 4; // Emit PC-relative addr of New code.
39 /// JITCompilerFunction - This contains the address of the JIT function used to
40 /// compile a function lazily.
41 static TargetJITInfo::JITCompilerFn JITCompilerFunction;
43 // Get the ASMPREFIX for the current host. This is often '_'.
44 #ifndef __USER_LABEL_PREFIX__
45 #define __USER_LABEL_PREFIX__
47 #define GETASMPREFIX2(X) #X
48 #define GETASMPREFIX(X) GETASMPREFIX2(X)
49 #define ASMPREFIX GETASMPREFIX(__USER_LABEL_PREFIX__)
51 // Provide a wrapper for X86CompilationCallback2 that saves non-traditional
52 // callee saved registers, for the fastcc calling convention.
54 #if defined(__x86_64__)
55 // No need to save EAX/EDX for X86-64.
56 void X86CompilationCallback(void);
60 ".globl " ASMPREFIX "X86CompilationCallback\n"
61 ASMPREFIX "X86CompilationCallback:\n"
66 // Save all int arg registers
73 // Align stack on 16-byte boundary. ESP might not be properly aligned
74 // (8 byte) if this is called from an indirect stub.
76 // Save all XMM arg registers
78 "movaps %xmm0, (%rsp)\n"
79 "movaps %xmm1, 16(%rsp)\n"
80 "movaps %xmm2, 32(%rsp)\n"
81 "movaps %xmm3, 48(%rsp)\n"
82 "movaps %xmm4, 64(%rsp)\n"
83 "movaps %xmm5, 80(%rsp)\n"
84 "movaps %xmm6, 96(%rsp)\n"
85 "movaps %xmm7, 112(%rsp)\n"
87 "movq %rbp, %rdi\n" // Pass prev frame and return address
88 "movq 8(%rbp), %rsi\n"
89 "call " ASMPREFIX "X86CompilationCallback2\n"
90 // Restore all XMM arg registers
91 "movaps 112(%rsp), %xmm7\n"
92 "movaps 96(%rsp), %xmm6\n"
93 "movaps 80(%rsp), %xmm5\n"
94 "movaps 64(%rsp), %xmm4\n"
95 "movaps 48(%rsp), %xmm3\n"
96 "movaps 32(%rsp), %xmm2\n"
97 "movaps 16(%rsp), %xmm1\n"
98 "movaps (%rsp), %xmm0\n"
101 // Restore all int arg registers
112 #elif defined(__i386__) || defined(i386) || defined(_M_IX86)
114 void X86CompilationCallback(void);
118 ".globl " ASMPREFIX "X86CompilationCallback\n"
119 ASMPREFIX "X86CompilationCallback:\n"
121 "movl %esp, %ebp\n" // Standard prologue
122 #if FASTCC_NUM_INT_ARGS_INREGS > 0
124 "pushl %edx\n" // Save EAX/EDX
126 #if defined(__APPLE__)
127 "andl $-16, %esp\n" // Align ESP on 16-byte boundary
130 "movl 4(%ebp), %eax\n" // Pass prev frame and return address
131 "movl %eax, 4(%esp)\n"
132 "movl %ebp, (%esp)\n"
133 "call " ASMPREFIX "X86CompilationCallback2\n"
134 "movl %ebp, %esp\n" // Restore ESP
135 #if FASTCC_NUM_INT_ARGS_INREGS > 0
143 // Same as X86CompilationCallback but also saves XMM argument registers.
144 void X86CompilationCallback_SSE(void);
148 ".globl " ASMPREFIX "X86CompilationCallback_SSE\n"
149 ASMPREFIX "X86CompilationCallback_SSE:\n"
151 "movl %esp, %ebp\n" // Standard prologue
152 #if FASTCC_NUM_INT_ARGS_INREGS > 0
154 "pushl %edx\n" // Save EAX/EDX
156 "andl $-16, %esp\n" // Align ESP on 16-byte boundary
157 // Save all XMM arg registers
159 "movaps %xmm0, (%esp)\n"
160 "movaps %xmm1, 16(%esp)\n"
161 "movaps %xmm2, 32(%esp)\n"
162 "movaps %xmm3, 48(%esp)\n"
164 "movl 4(%ebp), %eax\n" // Pass prev frame and return address
165 "movl %eax, 4(%esp)\n"
166 "movl %ebp, (%esp)\n"
167 "call " ASMPREFIX "X86CompilationCallback2\n"
169 "movaps 48(%esp), %xmm3\n"
170 "movaps 32(%esp), %xmm2\n"
171 "movaps 16(%esp), %xmm1\n"
172 "movaps (%esp), %xmm0\n"
173 "movl %ebp, %esp\n" // Restore ESP
174 #if FASTCC_NUM_INT_ARGS_INREGS > 0
182 void X86CompilationCallback2(void);
184 _declspec(naked) void X86CompilationCallback(void) {
188 call X86CompilationCallback2
196 #else // Not an i386 host
197 void X86CompilationCallback() {
198 std::cerr << "Cannot call X86CompilationCallback() on a non-x86 arch!\n";
204 /// X86CompilationCallback - This is the target-specific function invoked by the
205 /// function stub when we did not know the real target of a call. This function
206 /// must locate the start of the stub or call site and pass it into the JIT
207 /// compiler function.
209 extern "C" void X86CompilationCallback2() {
210 assert(sizeof(size_t) == 4); // FIXME: handle Win64
211 unsigned *RetAddrLoc = (unsigned *)_AddressOfReturnAddress();
212 RetAddrLoc += 3; // skip over ret addr, edx, eax
213 unsigned RetAddr = *RetAddrLoc;
215 extern "C" void X86CompilationCallback2(intptr_t *StackPtr, intptr_t RetAddr) {
216 intptr_t *RetAddrLoc = &StackPtr[1];
218 assert(*RetAddrLoc == RetAddr &&
219 "Could not find return address on the stack!");
221 // It's a stub if there is an interrupt marker after the call.
222 bool isStub = ((unsigned char*)RetAddr)[0] == 0xCD;
224 // The call instruction should have pushed the return value onto the stack...
225 RetAddr -= 4; // Backtrack to the reference itself...
228 DEBUG(std::cerr << "In callback! Addr=" << (void*)RetAddr
229 << " ESP=" << (void*)StackPtr
230 << ": Resolving call to function: "
231 << TheVM->getFunctionReferencedName((void*)RetAddr) << "\n");
234 // Sanity check to make sure this really is a call instruction.
235 assert(((unsigned char*)RetAddr)[-1] == 0xE8 &&"Not a call instr!");
237 intptr_t NewVal = (intptr_t)JITCompilerFunction((void*)RetAddr);
239 // Rewrite the call target... so that we don't end up here every time we
241 *(unsigned *)RetAddr = (unsigned)(NewVal-RetAddr-4);
244 // If this is a stub, rewrite the call into an unconditional branch
245 // instruction so that two return addresses are not pushed onto the stack
246 // when the requested function finally gets called. This also makes the
247 // 0xCD byte (interrupt) dead, so the marker doesn't effect anything.
248 ((unsigned char*)RetAddr)[-1] = 0xE9;
251 // Change the return address to reexecute the call instruction...
255 TargetJITInfo::LazyResolverFn
256 X86JITInfo::getLazyResolverFunction(JITCompilerFn F) {
257 JITCompilerFunction = F;
259 #if (defined(__i386__) || defined(i386) || defined(_M_IX86)) && \
260 !defined(_MSC_VER) && !defined(__x86_64__)
261 unsigned EAX = 0, EBX = 0, ECX = 0, EDX = 0;
267 if (!X86::GetCpuIDAndInfo(0, &EAX, text.u+0, text.u+2, text.u+1)) {
268 // FIXME: support for AMD family of processors.
269 if (memcmp(text.c, "GenuineIntel", 12) == 0) {
270 X86::GetCpuIDAndInfo(0x1, &EAX, &EBX, &ECX, &EDX);
271 if ((EDX >> 25) & 0x1)
272 return X86CompilationCallback_SSE;
277 return X86CompilationCallback;
280 void *X86JITInfo::emitFunctionStub(void *Fn, MachineCodeEmitter &MCE) {
281 // Note, we cast to intptr_t here to silence a -pedantic warning that
282 // complains about casting a function pointer to a normal pointer.
283 #if (defined(__i386__) || defined(i386) || defined(_M_IX86)) && \
284 !defined(_MSC_VER) && !defined(__x86_64__)
285 bool NotCC = (Fn != (void*)(intptr_t)X86CompilationCallback &&
286 Fn != (void*)(intptr_t)X86CompilationCallback_SSE);
288 bool NotCC = Fn != (void*)(intptr_t)X86CompilationCallback;
291 MCE.startFunctionStub(5);
293 MCE.emitWordLE((intptr_t)Fn-MCE.getCurrentPCValue()-4);
294 return MCE.finishFunctionStub(0);
297 MCE.startFunctionStub(6);
298 MCE.emitByte(0xE8); // Call with 32 bit pc-rel destination...
300 MCE.emitWordLE((intptr_t)Fn-MCE.getCurrentPCValue()-4);
302 MCE.emitByte(0xCD); // Interrupt - Just a marker identifying the stub!
303 return MCE.finishFunctionStub(0);
306 /// relocate - Before the JIT can run a block of code that has been emitted,
307 /// it must rewrite the code to contain the actual addresses of any
308 /// referenced global symbols.
309 void X86JITInfo::relocate(void *Function, MachineRelocation *MR,
310 unsigned NumRelocs, unsigned char* GOTBase) {
311 for (unsigned i = 0; i != NumRelocs; ++i, ++MR) {
312 void *RelocPos = (char*)Function + MR->getMachineCodeOffset();
313 intptr_t ResultPtr = (intptr_t)MR->getResultPointer();
314 switch ((X86::RelocationType)MR->getRelocationType()) {
315 case X86::reloc_pcrel_word: {
316 // PC relative relocation, add the relocated value to the value already in
317 // memory, after we adjust it for where the PC is.
318 ResultPtr = ResultPtr-(intptr_t)RelocPos-4-MR->getConstantVal();
319 *((unsigned*)RelocPos) += (unsigned)ResultPtr;
322 case X86::reloc_absolute_word:
323 // Absolute relocation, just add the relocated value to the value already
325 *((unsigned*)RelocPos) += (unsigned)ResultPtr;