1 //===-- X86JITInfo.cpp - Implement the JIT interfaces for the X86 target --===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // 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 "X86TargetMachine.h"
19 #include "llvm/IR/Function.h"
20 #include "llvm/Support/Compiler.h"
21 #include "llvm/Support/ErrorHandling.h"
22 #include "llvm/Support/Valgrind.h"
27 // Determine the platform we're running on
28 #if defined (__x86_64__) || defined (_M_AMD64) || defined (_M_X64)
30 #elif defined(__i386__) || defined(i386) || defined(_M_IX86)
34 void X86JITInfo::replaceMachineCodeForFunction(void *Old, void *New) {
35 unsigned char *OldByte = (unsigned char *)Old;
36 *OldByte++ = 0xE9; // Emit JMP opcode.
37 unsigned *OldWord = (unsigned *)OldByte;
38 unsigned NewAddr = (intptr_t)New;
39 unsigned OldAddr = (intptr_t)OldWord;
40 *OldWord = NewAddr - OldAddr - 4; // Emit PC-relative addr of New code.
42 // X86 doesn't need to invalidate the processor cache, so just invalidate
43 // Valgrind's cache directly.
44 sys::ValgrindDiscardTranslations(Old, 5);
48 /// JITCompilerFunction - This contains the address of the JIT function used to
49 /// compile a function lazily.
50 static TargetJITInfo::JITCompilerFn JITCompilerFunction;
52 // Get the ASMPREFIX for the current host. This is often '_'.
53 #ifndef __USER_LABEL_PREFIX__
54 #define __USER_LABEL_PREFIX__
56 #define GETASMPREFIX2(X) #X
57 #define GETASMPREFIX(X) GETASMPREFIX2(X)
58 #define ASMPREFIX GETASMPREFIX(__USER_LABEL_PREFIX__)
60 // For ELF targets, use a .size and .type directive, to let tools
61 // know the extent of functions defined in assembler.
63 # define SIZE(sym) ".size " #sym ", . - " #sym "\n"
64 # define TYPE_FUNCTION(sym) ".type " #sym ", @function\n"
67 # define TYPE_FUNCTION(sym)
70 // Provide a convenient way for disabling usage of CFI directives.
71 // This is needed for old/broken assemblers (for example, gas on
72 // Darwin is pretty old and doesn't support these directives)
73 #if defined(__APPLE__)
76 // FIXME: Disable this until we really want to use it. Also, we will
77 // need to add some workarounds for compilers, which support
78 // only subset of these directives.
82 // Provide a wrapper for LLVMX86CompilationCallback2 that saves non-traditional
83 // callee saved registers, for the fastcc calling convention.
85 #if defined(X86_64_JIT)
87 // No need to save EAX/EDX for X86-64.
88 void X86CompilationCallback(void);
92 ".globl " ASMPREFIX "X86CompilationCallback\n"
93 TYPE_FUNCTION(X86CompilationCallback)
94 ASMPREFIX "X86CompilationCallback:\n"
95 CFI(".cfi_startproc\n")
98 CFI(".cfi_def_cfa_offset 16\n")
99 CFI(".cfi_offset %rbp, -16\n")
102 CFI(".cfi_def_cfa_register %rbp\n")
103 // Save all int arg registers
105 CFI(".cfi_rel_offset %rdi, 0\n")
107 CFI(".cfi_rel_offset %rsi, 8\n")
109 CFI(".cfi_rel_offset %rdx, 16\n")
111 CFI(".cfi_rel_offset %rcx, 24\n")
113 CFI(".cfi_rel_offset %r8, 32\n")
115 CFI(".cfi_rel_offset %r9, 40\n")
116 // Align stack on 16-byte boundary. ESP might not be properly aligned
117 // (8 byte) if this is called from an indirect stub.
119 // Save all XMM arg registers
121 "movaps %xmm0, (%rsp)\n"
122 "movaps %xmm1, 16(%rsp)\n"
123 "movaps %xmm2, 32(%rsp)\n"
124 "movaps %xmm3, 48(%rsp)\n"
125 "movaps %xmm4, 64(%rsp)\n"
126 "movaps %xmm5, 80(%rsp)\n"
127 "movaps %xmm6, 96(%rsp)\n"
128 "movaps %xmm7, 112(%rsp)\n"
132 "movq %rbp, %rcx\n" // Pass prev frame and return address
133 "movq 8(%rbp), %rdx\n"
134 "call " ASMPREFIX "LLVMX86CompilationCallback2\n"
137 "movq %rbp, %rdi\n" // Pass prev frame and return address
138 "movq 8(%rbp), %rsi\n"
139 "call " ASMPREFIX "LLVMX86CompilationCallback2\n"
141 // Restore all XMM arg registers
142 "movaps 112(%rsp), %xmm7\n"
143 "movaps 96(%rsp), %xmm6\n"
144 "movaps 80(%rsp), %xmm5\n"
145 "movaps 64(%rsp), %xmm4\n"
146 "movaps 48(%rsp), %xmm3\n"
147 "movaps 32(%rsp), %xmm2\n"
148 "movaps 16(%rsp), %xmm1\n"
149 "movaps (%rsp), %xmm0\n"
152 CFI(".cfi_def_cfa_register %rsp\n")
153 // Restore all int arg registers
155 CFI(".cfi_adjust_cfa_offset 48\n")
157 CFI(".cfi_adjust_cfa_offset -8\n")
158 CFI(".cfi_restore %r9\n")
160 CFI(".cfi_adjust_cfa_offset -8\n")
161 CFI(".cfi_restore %r8\n")
163 CFI(".cfi_adjust_cfa_offset -8\n")
164 CFI(".cfi_restore %rcx\n")
166 CFI(".cfi_adjust_cfa_offset -8\n")
167 CFI(".cfi_restore %rdx\n")
169 CFI(".cfi_adjust_cfa_offset -8\n")
170 CFI(".cfi_restore %rsi\n")
172 CFI(".cfi_adjust_cfa_offset -8\n")
173 CFI(".cfi_restore %rdi\n")
176 CFI(".cfi_adjust_cfa_offset -8\n")
177 CFI(".cfi_restore %rbp\n")
179 CFI(".cfi_endproc\n")
180 SIZE(X86CompilationCallback)
183 // No inline assembler support on this platform. The routine is in external
185 void X86CompilationCallback();
188 #elif defined (X86_32_JIT)
190 void X86CompilationCallback(void);
194 ".globl " ASMPREFIX "X86CompilationCallback\n"
195 TYPE_FUNCTION(X86CompilationCallback)
196 ASMPREFIX "X86CompilationCallback:\n"
197 CFI(".cfi_startproc\n")
199 CFI(".cfi_def_cfa_offset 8\n")
200 CFI(".cfi_offset %ebp, -8\n")
201 "movl %esp, %ebp\n" // Standard prologue
202 CFI(".cfi_def_cfa_register %ebp\n")
204 CFI(".cfi_rel_offset %eax, 0\n")
205 "pushl %edx\n" // Save EAX/EDX/ECX
206 CFI(".cfi_rel_offset %edx, 4\n")
208 CFI(".cfi_rel_offset %ecx, 8\n")
209 # if defined(__APPLE__)
210 "andl $-16, %esp\n" // Align ESP on 16-byte boundary
213 "movl 4(%ebp), %eax\n" // Pass prev frame and return address
214 "movl %eax, 4(%esp)\n"
215 "movl %ebp, (%esp)\n"
216 "call " ASMPREFIX "LLVMX86CompilationCallback2\n"
217 "movl %ebp, %esp\n" // Restore ESP
218 CFI(".cfi_def_cfa_register %esp\n")
220 CFI(".cfi_adjust_cfa_offset 12\n")
222 CFI(".cfi_adjust_cfa_offset -4\n")
223 CFI(".cfi_restore %ecx\n")
225 CFI(".cfi_adjust_cfa_offset -4\n")
226 CFI(".cfi_restore %edx\n")
228 CFI(".cfi_adjust_cfa_offset -4\n")
229 CFI(".cfi_restore %eax\n")
231 CFI(".cfi_adjust_cfa_offset -4\n")
232 CFI(".cfi_restore %ebp\n")
234 CFI(".cfi_endproc\n")
235 SIZE(X86CompilationCallback)
238 // Same as X86CompilationCallback but also saves XMM argument registers.
239 void X86CompilationCallback_SSE(void);
243 ".globl " ASMPREFIX "X86CompilationCallback_SSE\n"
244 TYPE_FUNCTION(X86CompilationCallback_SSE)
245 ASMPREFIX "X86CompilationCallback_SSE:\n"
246 CFI(".cfi_startproc\n")
248 CFI(".cfi_def_cfa_offset 8\n")
249 CFI(".cfi_offset %ebp, -8\n")
250 "movl %esp, %ebp\n" // Standard prologue
251 CFI(".cfi_def_cfa_register %ebp\n")
253 CFI(".cfi_rel_offset %eax, 0\n")
254 "pushl %edx\n" // Save EAX/EDX/ECX
255 CFI(".cfi_rel_offset %edx, 4\n")
257 CFI(".cfi_rel_offset %ecx, 8\n")
258 "andl $-16, %esp\n" // Align ESP on 16-byte boundary
259 // Save all XMM arg registers
261 // FIXME: provide frame move information for xmm registers.
262 // This can be tricky, because CFA register is ebp (unaligned)
263 // and we need to produce offsets relative to it.
264 "movaps %xmm0, (%esp)\n"
265 "movaps %xmm1, 16(%esp)\n"
266 "movaps %xmm2, 32(%esp)\n"
267 "movaps %xmm3, 48(%esp)\n"
269 "movl 4(%ebp), %eax\n" // Pass prev frame and return address
270 "movl %eax, 4(%esp)\n"
271 "movl %ebp, (%esp)\n"
272 "call " ASMPREFIX "LLVMX86CompilationCallback2\n"
274 "movaps 48(%esp), %xmm3\n"
275 CFI(".cfi_restore %xmm3\n")
276 "movaps 32(%esp), %xmm2\n"
277 CFI(".cfi_restore %xmm2\n")
278 "movaps 16(%esp), %xmm1\n"
279 CFI(".cfi_restore %xmm1\n")
280 "movaps (%esp), %xmm0\n"
281 CFI(".cfi_restore %xmm0\n")
282 "movl %ebp, %esp\n" // Restore ESP
283 CFI(".cfi_def_cfa_register esp\n")
285 CFI(".cfi_adjust_cfa_offset 12\n")
287 CFI(".cfi_adjust_cfa_offset -4\n")
288 CFI(".cfi_restore %ecx\n")
290 CFI(".cfi_adjust_cfa_offset -4\n")
291 CFI(".cfi_restore %edx\n")
293 CFI(".cfi_adjust_cfa_offset -4\n")
294 CFI(".cfi_restore %eax\n")
296 CFI(".cfi_adjust_cfa_offset -4\n")
297 CFI(".cfi_restore %ebp\n")
299 CFI(".cfi_endproc\n")
300 SIZE(X86CompilationCallback_SSE)
303 void LLVMX86CompilationCallback2(intptr_t *StackPtr, intptr_t RetAddr);
305 _declspec(naked) void X86CompilationCallback(void) {
314 mov eax, dword ptr [ebp+4]
315 mov dword ptr [esp+4], eax
316 mov dword ptr [esp], ebp
317 call LLVMX86CompilationCallback2
330 #else // Not an i386 host
331 void X86CompilationCallback() {
332 llvm_unreachable("Cannot call X86CompilationCallback() on a non-x86 arch!");
337 /// This is the target-specific function invoked by the
338 /// function stub when we did not know the real target of a call. This function
339 /// must locate the start of the stub or call site and pass it into the JIT
340 /// compiler function.
342 LLVM_LIBRARY_VISIBILITY void LLVMX86CompilationCallback2(intptr_t *StackPtr,
344 intptr_t *RetAddrLoc = &StackPtr[1];
345 // We are reading raw stack data here. Tell MemorySanitizer that it is
346 // sufficiently initialized.
347 __msan_unpoison(RetAddrLoc, sizeof(*RetAddrLoc));
348 assert(*RetAddrLoc == RetAddr &&
349 "Could not find return address on the stack!");
351 // It's a stub if there is an interrupt marker after the call.
352 bool isStub = ((unsigned char*)RetAddr)[0] == 0xCE;
354 // The call instruction should have pushed the return value onto the stack...
355 #if defined (X86_64_JIT)
356 RetAddr--; // Backtrack to the reference itself...
358 RetAddr -= 4; // Backtrack to the reference itself...
362 DEBUG(dbgs() << "In callback! Addr=" << (void*)RetAddr
363 << " ESP=" << (void*)StackPtr
364 << ": Resolving call to function: "
365 << TheVM->getFunctionReferencedName((void*)RetAddr) << "\n");
368 // Sanity check to make sure this really is a call instruction.
369 #if defined (X86_64_JIT)
370 assert(((unsigned char*)RetAddr)[-2] == 0x41 &&"Not a call instr!");
371 assert(((unsigned char*)RetAddr)[-1] == 0xFF &&"Not a call instr!");
373 assert(((unsigned char*)RetAddr)[-1] == 0xE8 &&"Not a call instr!");
376 intptr_t NewVal = (intptr_t)JITCompilerFunction((void*)RetAddr);
378 // Rewrite the call target... so that we don't end up here every time we
380 #if defined (X86_64_JIT)
382 "X86-64 doesn't support rewriting non-stub lazy compilation calls:"
383 " the call instruction varies too much.");
385 *(intptr_t *)RetAddr = (intptr_t)(NewVal-RetAddr-4);
389 // If this is a stub, rewrite the call into an unconditional branch
390 // instruction so that two return addresses are not pushed onto the stack
391 // when the requested function finally gets called. This also makes the
392 // 0xCE byte (interrupt) dead, so the marker doesn't effect anything.
393 #if defined (X86_64_JIT)
394 // If the target address is within 32-bit range of the stub, use a
395 // PC-relative branch instead of loading the actual address. (This is
396 // considerably shorter than the 64-bit immediate load already there.)
397 // We assume here intptr_t is 64 bits.
398 intptr_t diff = NewVal-RetAddr+7;
399 if (diff >= -2147483648LL && diff <= 2147483647LL) {
400 *(unsigned char*)(RetAddr-0xc) = 0xE9;
401 *(intptr_t *)(RetAddr-0xb) = diff & 0xffffffff;
403 *(intptr_t *)(RetAddr - 0xa) = NewVal;
404 ((unsigned char*)RetAddr)[0] = (2 | (4 << 3) | (3 << 6));
406 sys::ValgrindDiscardTranslations((void*)(RetAddr-0xc), 0xd);
408 ((unsigned char*)RetAddr)[-1] = 0xE9;
409 sys::ValgrindDiscardTranslations((void*)(RetAddr-1), 5);
413 // Change the return address to reexecute the call instruction...
414 #if defined (X86_64_JIT)
422 TargetJITInfo::LazyResolverFn
423 X86JITInfo::getLazyResolverFunction(JITCompilerFn F) {
424 TsanIgnoreWritesBegin();
425 JITCompilerFunction = F;
426 TsanIgnoreWritesEnd();
428 #if defined (X86_32_JIT) && !defined (_MSC_VER)
429 if (Subtarget->hasSSE1())
430 return X86CompilationCallback_SSE;
433 return X86CompilationCallback;
436 X86JITInfo::X86JITInfo(X86TargetMachine &tm) : TM(tm) {
437 Subtarget = &TM.getSubtarget<X86Subtarget>();
442 void *X86JITInfo::emitGlobalValueIndirectSym(const GlobalValue* GV, void *ptr,
443 JITCodeEmitter &JCE) {
444 #if defined (X86_64_JIT)
445 const unsigned Alignment = 8;
447 uint8_t *Cur = Buffer;
448 MachineCodeEmitter::emitWordLEInto(Cur, (unsigned)(intptr_t)ptr);
449 MachineCodeEmitter::emitWordLEInto(Cur, (unsigned)(((intptr_t)ptr) >> 32));
451 const unsigned Alignment = 4;
453 uint8_t *Cur = Buffer;
454 MachineCodeEmitter::emitWordLEInto(Cur, (intptr_t)ptr);
456 return JCE.allocIndirectGV(GV, Buffer, sizeof(Buffer), Alignment);
459 TargetJITInfo::StubLayout X86JITInfo::getStubLayout() {
460 // The 64-bit stub contains:
461 // movabs r10 <- 8-byte-target-address # 10 bytes
462 // call|jmp *r10 # 3 bytes
463 // The 32-bit stub contains a 5-byte call|jmp.
464 // If the stub is a call to the compilation callback, an extra byte is added
465 // to mark it as a stub.
466 StubLayout Result = {14, 4};
470 void *X86JITInfo::emitFunctionStub(const Function* F, void *Target,
471 JITCodeEmitter &JCE) {
472 // Note, we cast to intptr_t here to silence a -pedantic warning that
473 // complains about casting a function pointer to a normal pointer.
474 #if defined (X86_32_JIT) && !defined (_MSC_VER)
475 bool NotCC = (Target != (void*)(intptr_t)X86CompilationCallback &&
476 Target != (void*)(intptr_t)X86CompilationCallback_SSE);
478 bool NotCC = Target != (void*)(intptr_t)X86CompilationCallback;
480 JCE.emitAlignment(4);
481 void *Result = (void*)JCE.getCurrentPCValue();
483 #if defined (X86_64_JIT)
484 JCE.emitByte(0x49); // REX prefix
485 JCE.emitByte(0xB8+2); // movabsq r10
486 JCE.emitWordLE((unsigned)(intptr_t)Target);
487 JCE.emitWordLE((unsigned)(((intptr_t)Target) >> 32));
488 JCE.emitByte(0x41); // REX prefix
489 JCE.emitByte(0xFF); // jmpq *r10
490 JCE.emitByte(2 | (4 << 3) | (3 << 6));
493 JCE.emitWordLE((intptr_t)Target-JCE.getCurrentPCValue()-4);
498 #if defined (X86_64_JIT)
499 JCE.emitByte(0x49); // REX prefix
500 JCE.emitByte(0xB8+2); // movabsq r10
501 JCE.emitWordLE((unsigned)(intptr_t)Target);
502 JCE.emitWordLE((unsigned)(((intptr_t)Target) >> 32));
503 JCE.emitByte(0x41); // REX prefix
504 JCE.emitByte(0xFF); // callq *r10
505 JCE.emitByte(2 | (2 << 3) | (3 << 6));
507 JCE.emitByte(0xE8); // Call with 32 bit pc-rel destination...
509 JCE.emitWordLE((intptr_t)Target-JCE.getCurrentPCValue()-4);
512 // This used to use 0xCD, but that value is used by JITMemoryManager to
513 // initialize the buffer with garbage, which means it may follow a
514 // noreturn function call, confusing LLVMX86CompilationCallback2. PR 4929.
515 JCE.emitByte(0xCE); // Interrupt - Just a marker identifying the stub!
519 /// getPICJumpTableEntry - Returns the value of the jumptable entry for the
520 /// specific basic block.
521 uintptr_t X86JITInfo::getPICJumpTableEntry(uintptr_t BB, uintptr_t Entry) {
522 #if defined(X86_64_JIT)
529 template<typename T> static void addUnaligned(void *Pos, T Delta) {
531 std::memcpy(reinterpret_cast<char*>(&Value), reinterpret_cast<char*>(Pos),
534 std::memcpy(reinterpret_cast<char*>(Pos), reinterpret_cast<char*>(&Value),
538 /// relocate - Before the JIT can run a block of code that has been emitted,
539 /// it must rewrite the code to contain the actual addresses of any
540 /// referenced global symbols.
541 void X86JITInfo::relocate(void *Function, MachineRelocation *MR,
542 unsigned NumRelocs, unsigned char* GOTBase) {
543 for (unsigned i = 0; i != NumRelocs; ++i, ++MR) {
544 void *RelocPos = (char*)Function + MR->getMachineCodeOffset();
545 intptr_t ResultPtr = (intptr_t)MR->getResultPointer();
546 switch ((X86::RelocationType)MR->getRelocationType()) {
547 case X86::reloc_pcrel_word: {
548 // PC relative relocation, add the relocated value to the value already in
549 // memory, after we adjust it for where the PC is.
550 ResultPtr = ResultPtr -(intptr_t)RelocPos - 4 - MR->getConstantVal();
551 addUnaligned<unsigned>(RelocPos, ResultPtr);
554 case X86::reloc_picrel_word: {
555 // PIC base relative relocation, add the relocated value to the value
556 // already in memory, after we adjust it for where the PIC base is.
557 ResultPtr = ResultPtr - ((intptr_t)Function + MR->getConstantVal());
558 addUnaligned<unsigned>(RelocPos, ResultPtr);
561 case X86::reloc_absolute_word:
562 case X86::reloc_absolute_word_sext:
563 // Absolute relocation, just add the relocated value to the value already
565 addUnaligned<unsigned>(RelocPos, ResultPtr);
567 case X86::reloc_absolute_dword:
568 addUnaligned<intptr_t>(RelocPos, ResultPtr);
574 char* X86JITInfo::allocateThreadLocalMemory(size_t size) {
575 #if defined(X86_32_JIT) && !defined(__APPLE__) && !defined(_MSC_VER)
579 llvm_unreachable("Cannot allocate thread local storage on this arch!");