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llvm-6502/lib/Target/X86/X86JITInfo.cpp
Nick Lewycky 3604924799 Creating multiple JITs on X86 in multiple threads causes multiple writes (of 
the same value) to this variable. This code could be refactored, but it doesn't
matter since the old JIT is going away. Add tsan annotations to ignore the
race.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@145745 91177308-0d34-0410-b5e6-96231b3b80d8
2011-12-03 02:45:50 +00:00

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//===-- X86JITInfo.cpp - Implement the JIT interfaces for the X86 target --===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the JIT interfaces for the X86 target.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "jit"
#include "X86JITInfo.h"
#include "X86Relocations.h"
#include "X86Subtarget.h"
#include "X86TargetMachine.h"
#include "llvm/Function.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/Valgrind.h"
#include <cstdlib>
#include <cstring>
using namespace llvm;
// Determine the platform we're running on
#if defined (__x86_64__) || defined (_M_AMD64) || defined (_M_X64)
# define X86_64_JIT
#elif defined(__i386__) || defined(i386) || defined(_M_IX86)
# define X86_32_JIT
#endif
void X86JITInfo::replaceMachineCodeForFunction(void *Old, void *New) {
unsigned char *OldByte = (unsigned char *)Old;
*OldByte++ = 0xE9; // Emit JMP opcode.
unsigned *OldWord = (unsigned *)OldByte;
unsigned NewAddr = (intptr_t)New;
unsigned OldAddr = (intptr_t)OldWord;
*OldWord = NewAddr - OldAddr - 4; // Emit PC-relative addr of New code.
// X86 doesn't need to invalidate the processor cache, so just invalidate
// Valgrind's cache directly.
sys::ValgrindDiscardTranslations(Old, 5);
}
/// JITCompilerFunction - This contains the address of the JIT function used to
/// compile a function lazily.
static TargetJITInfo::JITCompilerFn JITCompilerFunction;
// Get the ASMPREFIX for the current host. This is often '_'.
#ifndef __USER_LABEL_PREFIX__
#define __USER_LABEL_PREFIX__
#endif
#define GETASMPREFIX2(X) #X
#define GETASMPREFIX(X) GETASMPREFIX2(X)
#define ASMPREFIX GETASMPREFIX(__USER_LABEL_PREFIX__)
// For ELF targets, use a .size and .type directive, to let tools
// know the extent of functions defined in assembler.
#if defined(__ELF__)
# define SIZE(sym) ".size " #sym ", . - " #sym "\n"
# define TYPE_FUNCTION(sym) ".type " #sym ", @function\n"
#else
# define SIZE(sym)
# define TYPE_FUNCTION(sym)
#endif
// Provide a convenient way for disabling usage of CFI directives.
// This is needed for old/broken assemblers (for example, gas on
// Darwin is pretty old and doesn't support these directives)
#if defined(__APPLE__)
# define CFI(x)
#else
// FIXME: Disable this until we really want to use it. Also, we will
// need to add some workarounds for compilers, which support
// only subset of these directives.
# define CFI(x)
#endif
// Provide a wrapper for X86CompilationCallback2 that saves non-traditional
// callee saved registers, for the fastcc calling convention.
extern "C" {
#if defined(X86_64_JIT)
# ifndef _MSC_VER
// No need to save EAX/EDX for X86-64.
void X86CompilationCallback(void);
asm(
".text\n"
".align 8\n"
".globl " ASMPREFIX "X86CompilationCallback\n"
TYPE_FUNCTION(X86CompilationCallback)
ASMPREFIX "X86CompilationCallback:\n"
CFI(".cfi_startproc\n")
// Save RBP
"pushq %rbp\n"
CFI(".cfi_def_cfa_offset 16\n")
CFI(".cfi_offset %rbp, -16\n")
// Save RSP
"movq %rsp, %rbp\n"
CFI(".cfi_def_cfa_register %rbp\n")
// Save all int arg registers
"pushq %rdi\n"
CFI(".cfi_rel_offset %rdi, 0\n")
"pushq %rsi\n"
CFI(".cfi_rel_offset %rsi, 8\n")
"pushq %rdx\n"
CFI(".cfi_rel_offset %rdx, 16\n")
"pushq %rcx\n"
CFI(".cfi_rel_offset %rcx, 24\n")
"pushq %r8\n"
CFI(".cfi_rel_offset %r8, 32\n")
"pushq %r9\n"
CFI(".cfi_rel_offset %r9, 40\n")
// Align stack on 16-byte boundary. ESP might not be properly aligned
// (8 byte) if this is called from an indirect stub.
"andq $-16, %rsp\n"
// Save all XMM arg registers
"subq $128, %rsp\n"
"movaps %xmm0, (%rsp)\n"
"movaps %xmm1, 16(%rsp)\n"
"movaps %xmm2, 32(%rsp)\n"
"movaps %xmm3, 48(%rsp)\n"
"movaps %xmm4, 64(%rsp)\n"
"movaps %xmm5, 80(%rsp)\n"
"movaps %xmm6, 96(%rsp)\n"
"movaps %xmm7, 112(%rsp)\n"
// JIT callee
#ifdef _WIN64
"subq $32, %rsp\n"
"movq %rbp, %rcx\n" // Pass prev frame and return address
"movq 8(%rbp), %rdx\n"
"call " ASMPREFIX "X86CompilationCallback2\n"
"addq $32, %rsp\n"
#else
"movq %rbp, %rdi\n" // Pass prev frame and return address
"movq 8(%rbp), %rsi\n"
"call " ASMPREFIX "X86CompilationCallback2\n"
#endif
// Restore all XMM arg registers
"movaps 112(%rsp), %xmm7\n"
"movaps 96(%rsp), %xmm6\n"
"movaps 80(%rsp), %xmm5\n"
"movaps 64(%rsp), %xmm4\n"
"movaps 48(%rsp), %xmm3\n"
"movaps 32(%rsp), %xmm2\n"
"movaps 16(%rsp), %xmm1\n"
"movaps (%rsp), %xmm0\n"
// Restore RSP
"movq %rbp, %rsp\n"
CFI(".cfi_def_cfa_register %rsp\n")
// Restore all int arg registers
"subq $48, %rsp\n"
CFI(".cfi_adjust_cfa_offset 48\n")
"popq %r9\n"
CFI(".cfi_adjust_cfa_offset -8\n")
CFI(".cfi_restore %r9\n")
"popq %r8\n"
CFI(".cfi_adjust_cfa_offset -8\n")
CFI(".cfi_restore %r8\n")
"popq %rcx\n"
CFI(".cfi_adjust_cfa_offset -8\n")
CFI(".cfi_restore %rcx\n")
"popq %rdx\n"
CFI(".cfi_adjust_cfa_offset -8\n")
CFI(".cfi_restore %rdx\n")
"popq %rsi\n"
CFI(".cfi_adjust_cfa_offset -8\n")
CFI(".cfi_restore %rsi\n")
"popq %rdi\n"
CFI(".cfi_adjust_cfa_offset -8\n")
CFI(".cfi_restore %rdi\n")
// Restore RBP
"popq %rbp\n"
CFI(".cfi_adjust_cfa_offset -8\n")
CFI(".cfi_restore %rbp\n")
"ret\n"
CFI(".cfi_endproc\n")
SIZE(X86CompilationCallback)
);
# else
// No inline assembler support on this platform. The routine is in external
// file.
void X86CompilationCallback();
# endif
#elif defined (X86_32_JIT)
# ifndef _MSC_VER
void X86CompilationCallback(void);
asm(
".text\n"
".align 8\n"
".globl " ASMPREFIX "X86CompilationCallback\n"
TYPE_FUNCTION(X86CompilationCallback)
ASMPREFIX "X86CompilationCallback:\n"
CFI(".cfi_startproc\n")
"pushl %ebp\n"
CFI(".cfi_def_cfa_offset 8\n")
CFI(".cfi_offset %ebp, -8\n")
"movl %esp, %ebp\n" // Standard prologue
CFI(".cfi_def_cfa_register %ebp\n")
"pushl %eax\n"
CFI(".cfi_rel_offset %eax, 0\n")
"pushl %edx\n" // Save EAX/EDX/ECX
CFI(".cfi_rel_offset %edx, 4\n")
"pushl %ecx\n"
CFI(".cfi_rel_offset %ecx, 8\n")
# if defined(__APPLE__)
"andl $-16, %esp\n" // Align ESP on 16-byte boundary
# endif
"subl $16, %esp\n"
"movl 4(%ebp), %eax\n" // Pass prev frame and return address
"movl %eax, 4(%esp)\n"
"movl %ebp, (%esp)\n"
"call " ASMPREFIX "X86CompilationCallback2\n"
"movl %ebp, %esp\n" // Restore ESP
CFI(".cfi_def_cfa_register %esp\n")
"subl $12, %esp\n"
CFI(".cfi_adjust_cfa_offset 12\n")
"popl %ecx\n"
CFI(".cfi_adjust_cfa_offset -4\n")
CFI(".cfi_restore %ecx\n")
"popl %edx\n"
CFI(".cfi_adjust_cfa_offset -4\n")
CFI(".cfi_restore %edx\n")
"popl %eax\n"
CFI(".cfi_adjust_cfa_offset -4\n")
CFI(".cfi_restore %eax\n")
"popl %ebp\n"
CFI(".cfi_adjust_cfa_offset -4\n")
CFI(".cfi_restore %ebp\n")
"ret\n"
CFI(".cfi_endproc\n")
SIZE(X86CompilationCallback)
);
// Same as X86CompilationCallback but also saves XMM argument registers.
void X86CompilationCallback_SSE(void);
asm(
".text\n"
".align 8\n"
".globl " ASMPREFIX "X86CompilationCallback_SSE\n"
TYPE_FUNCTION(X86CompilationCallback_SSE)
ASMPREFIX "X86CompilationCallback_SSE:\n"
CFI(".cfi_startproc\n")
"pushl %ebp\n"
CFI(".cfi_def_cfa_offset 8\n")
CFI(".cfi_offset %ebp, -8\n")
"movl %esp, %ebp\n" // Standard prologue
CFI(".cfi_def_cfa_register %ebp\n")
"pushl %eax\n"
CFI(".cfi_rel_offset %eax, 0\n")
"pushl %edx\n" // Save EAX/EDX/ECX
CFI(".cfi_rel_offset %edx, 4\n")
"pushl %ecx\n"
CFI(".cfi_rel_offset %ecx, 8\n")
"andl $-16, %esp\n" // Align ESP on 16-byte boundary
// Save all XMM arg registers
"subl $64, %esp\n"
// FIXME: provide frame move information for xmm registers.
// This can be tricky, because CFA register is ebp (unaligned)
// and we need to produce offsets relative to it.
"movaps %xmm0, (%esp)\n"
"movaps %xmm1, 16(%esp)\n"
"movaps %xmm2, 32(%esp)\n"
"movaps %xmm3, 48(%esp)\n"
"subl $16, %esp\n"
"movl 4(%ebp), %eax\n" // Pass prev frame and return address
"movl %eax, 4(%esp)\n"
"movl %ebp, (%esp)\n"
"call " ASMPREFIX "X86CompilationCallback2\n"
"addl $16, %esp\n"
"movaps 48(%esp), %xmm3\n"
CFI(".cfi_restore %xmm3\n")
"movaps 32(%esp), %xmm2\n"
CFI(".cfi_restore %xmm2\n")
"movaps 16(%esp), %xmm1\n"
CFI(".cfi_restore %xmm1\n")
"movaps (%esp), %xmm0\n"
CFI(".cfi_restore %xmm0\n")
"movl %ebp, %esp\n" // Restore ESP
CFI(".cfi_def_cfa_register esp\n")
"subl $12, %esp\n"
CFI(".cfi_adjust_cfa_offset 12\n")
"popl %ecx\n"
CFI(".cfi_adjust_cfa_offset -4\n")
CFI(".cfi_restore %ecx\n")
"popl %edx\n"
CFI(".cfi_adjust_cfa_offset -4\n")
CFI(".cfi_restore %edx\n")
"popl %eax\n"
CFI(".cfi_adjust_cfa_offset -4\n")
CFI(".cfi_restore %eax\n")
"popl %ebp\n"
CFI(".cfi_adjust_cfa_offset -4\n")
CFI(".cfi_restore %ebp\n")
"ret\n"
CFI(".cfi_endproc\n")
SIZE(X86CompilationCallback_SSE)
);
# else
void X86CompilationCallback2(intptr_t *StackPtr, intptr_t RetAddr);
_declspec(naked) void X86CompilationCallback(void) {
__asm {
push ebp
mov ebp, esp
push eax
push edx
push ecx
and esp, -16
sub esp, 16
mov eax, dword ptr [ebp+4]
mov dword ptr [esp+4], eax
mov dword ptr [esp], ebp
call X86CompilationCallback2
mov esp, ebp
sub esp, 12
pop ecx
pop edx
pop eax
pop ebp
ret
}
}
# endif // _MSC_VER
#else // Not an i386 host
void X86CompilationCallback() {
llvm_unreachable("Cannot call X86CompilationCallback() on a non-x86 arch!");
}
#endif
}
/// X86CompilationCallback2 - This is the target-specific function invoked by the
/// function stub when we did not know the real target of a call. This function
/// must locate the start of the stub or call site and pass it into the JIT
/// compiler function.
extern "C" {
#if !(defined (X86_64_JIT) && defined(_MSC_VER))
// the following function is called only from this translation unit,
// unless we are under 64bit Windows with MSC, where there is
// no support for inline assembly
static
#endif
void LLVM_ATTRIBUTE_USED
X86CompilationCallback2(intptr_t *StackPtr, intptr_t RetAddr) {
intptr_t *RetAddrLoc = &StackPtr[1];
assert(*RetAddrLoc == RetAddr &&
"Could not find return address on the stack!");
// It's a stub if there is an interrupt marker after the call.
bool isStub = ((unsigned char*)RetAddr)[0] == 0xCE;
// The call instruction should have pushed the return value onto the stack...
#if defined (X86_64_JIT)
RetAddr--; // Backtrack to the reference itself...
#else
RetAddr -= 4; // Backtrack to the reference itself...
#endif
#if 0
DEBUG(dbgs() << "In callback! Addr=" << (void*)RetAddr
<< " ESP=" << (void*)StackPtr
<< ": Resolving call to function: "
<< TheVM->getFunctionReferencedName((void*)RetAddr) << "\n");
#endif
// Sanity check to make sure this really is a call instruction.
#if defined (X86_64_JIT)
assert(((unsigned char*)RetAddr)[-2] == 0x41 &&"Not a call instr!");
assert(((unsigned char*)RetAddr)[-1] == 0xFF &&"Not a call instr!");
#else
assert(((unsigned char*)RetAddr)[-1] == 0xE8 &&"Not a call instr!");
#endif
intptr_t NewVal = (intptr_t)JITCompilerFunction((void*)RetAddr);
// Rewrite the call target... so that we don't end up here every time we
// execute the call.
#if defined (X86_64_JIT)
assert(isStub &&
"X86-64 doesn't support rewriting non-stub lazy compilation calls:"
" the call instruction varies too much.");
#else
*(intptr_t *)RetAddr = (intptr_t)(NewVal-RetAddr-4);
#endif
if (isStub) {
// If this is a stub, rewrite the call into an unconditional branch
// instruction so that two return addresses are not pushed onto the stack
// when the requested function finally gets called. This also makes the
// 0xCE byte (interrupt) dead, so the marker doesn't effect anything.
#if defined (X86_64_JIT)
// If the target address is within 32-bit range of the stub, use a
// PC-relative branch instead of loading the actual address. (This is
// considerably shorter than the 64-bit immediate load already there.)
// We assume here intptr_t is 64 bits.
intptr_t diff = NewVal-RetAddr+7;
if (diff >= -2147483648LL && diff <= 2147483647LL) {
*(unsigned char*)(RetAddr-0xc) = 0xE9;
*(intptr_t *)(RetAddr-0xb) = diff & 0xffffffff;
} else {
*(intptr_t *)(RetAddr - 0xa) = NewVal;
((unsigned char*)RetAddr)[0] = (2 | (4 << 3) | (3 << 6));
}
sys::ValgrindDiscardTranslations((void*)(RetAddr-0xc), 0xd);
#else
((unsigned char*)RetAddr)[-1] = 0xE9;
sys::ValgrindDiscardTranslations((void*)(RetAddr-1), 5);
#endif
}
// Change the return address to reexecute the call instruction...
#if defined (X86_64_JIT)
*RetAddrLoc -= 0xd;
#else
*RetAddrLoc -= 5;
#endif
}
}
TargetJITInfo::LazyResolverFn
X86JITInfo::getLazyResolverFunction(JITCompilerFn F) {
TsanIgnoreWritesBegin();
JITCompilerFunction = F;
TsanIgnoreWritesEnd();
#if defined (X86_32_JIT) && !defined (_MSC_VER)
if (Subtarget->hasSSE1())
return X86CompilationCallback_SSE;
#endif
return X86CompilationCallback;
}
X86JITInfo::X86JITInfo(X86TargetMachine &tm) : TM(tm) {
Subtarget = &TM.getSubtarget<X86Subtarget>();
useGOT = 0;
TLSOffset = 0;
}
void *X86JITInfo::emitGlobalValueIndirectSym(const GlobalValue* GV, void *ptr,
JITCodeEmitter &JCE) {
#if defined (X86_64_JIT)
const unsigned Alignment = 8;
uint8_t Buffer[8];
uint8_t *Cur = Buffer;
MachineCodeEmitter::emitWordLEInto(Cur, (unsigned)(intptr_t)ptr);
MachineCodeEmitter::emitWordLEInto(Cur, (unsigned)(((intptr_t)ptr) >> 32));
#else
const unsigned Alignment = 4;
uint8_t Buffer[4];
uint8_t *Cur = Buffer;
MachineCodeEmitter::emitWordLEInto(Cur, (intptr_t)ptr);
#endif
return JCE.allocIndirectGV(GV, Buffer, sizeof(Buffer), Alignment);
}
TargetJITInfo::StubLayout X86JITInfo::getStubLayout() {
// The 64-bit stub contains:
// movabs r10 <- 8-byte-target-address # 10 bytes
// call|jmp *r10 # 3 bytes
// The 32-bit stub contains a 5-byte call|jmp.
// If the stub is a call to the compilation callback, an extra byte is added
// to mark it as a stub.
StubLayout Result = {14, 4};
return Result;
}
void *X86JITInfo::emitFunctionStub(const Function* F, void *Target,
JITCodeEmitter &JCE) {
// Note, we cast to intptr_t here to silence a -pedantic warning that
// complains about casting a function pointer to a normal pointer.
#if defined (X86_32_JIT) && !defined (_MSC_VER)
bool NotCC = (Target != (void*)(intptr_t)X86CompilationCallback &&
Target != (void*)(intptr_t)X86CompilationCallback_SSE);
#else
bool NotCC = Target != (void*)(intptr_t)X86CompilationCallback;
#endif
JCE.emitAlignment(4);
void *Result = (void*)JCE.getCurrentPCValue();
if (NotCC) {
#if defined (X86_64_JIT)
JCE.emitByte(0x49); // REX prefix
JCE.emitByte(0xB8+2); // movabsq r10
JCE.emitWordLE((unsigned)(intptr_t)Target);
JCE.emitWordLE((unsigned)(((intptr_t)Target) >> 32));
JCE.emitByte(0x41); // REX prefix
JCE.emitByte(0xFF); // jmpq *r10
JCE.emitByte(2 | (4 << 3) | (3 << 6));
#else
JCE.emitByte(0xE9);
JCE.emitWordLE((intptr_t)Target-JCE.getCurrentPCValue()-4);
#endif
return Result;
}
#if defined (X86_64_JIT)
JCE.emitByte(0x49); // REX prefix
JCE.emitByte(0xB8+2); // movabsq r10
JCE.emitWordLE((unsigned)(intptr_t)Target);
JCE.emitWordLE((unsigned)(((intptr_t)Target) >> 32));
JCE.emitByte(0x41); // REX prefix
JCE.emitByte(0xFF); // callq *r10
JCE.emitByte(2 | (2 << 3) | (3 << 6));
#else
JCE.emitByte(0xE8); // Call with 32 bit pc-rel destination...
JCE.emitWordLE((intptr_t)Target-JCE.getCurrentPCValue()-4);
#endif
// This used to use 0xCD, but that value is used by JITMemoryManager to
// initialize the buffer with garbage, which means it may follow a
// noreturn function call, confusing X86CompilationCallback2. PR 4929.
JCE.emitByte(0xCE); // Interrupt - Just a marker identifying the stub!
return Result;
}
/// getPICJumpTableEntry - Returns the value of the jumptable entry for the
/// specific basic block.
uintptr_t X86JITInfo::getPICJumpTableEntry(uintptr_t BB, uintptr_t Entry) {
#if defined(X86_64_JIT)
return BB - Entry;
#else
return BB - PICBase;
#endif
}
/// relocate - Before the JIT can run a block of code that has been emitted,
/// it must rewrite the code to contain the actual addresses of any
/// referenced global symbols.
void X86JITInfo::relocate(void *Function, MachineRelocation *MR,
unsigned NumRelocs, unsigned char* GOTBase) {
for (unsigned i = 0; i != NumRelocs; ++i, ++MR) {
void *RelocPos = (char*)Function + MR->getMachineCodeOffset();
intptr_t ResultPtr = (intptr_t)MR->getResultPointer();
switch ((X86::RelocationType)MR->getRelocationType()) {
case X86::reloc_pcrel_word: {
// PC relative relocation, add the relocated value to the value already in
// memory, after we adjust it for where the PC is.
ResultPtr = ResultPtr -(intptr_t)RelocPos - 4 - MR->getConstantVal();
*((unsigned*)RelocPos) += (unsigned)ResultPtr;
break;
}
case X86::reloc_picrel_word: {
// PIC base relative relocation, add the relocated value to the value
// already in memory, after we adjust it for where the PIC base is.
ResultPtr = ResultPtr - ((intptr_t)Function + MR->getConstantVal());
*((unsigned*)RelocPos) += (unsigned)ResultPtr;
break;
}
case X86::reloc_absolute_word:
case X86::reloc_absolute_word_sext:
// Absolute relocation, just add the relocated value to the value already
// in memory.
*((unsigned*)RelocPos) += (unsigned)ResultPtr;
break;
case X86::reloc_absolute_dword:
*((intptr_t*)RelocPos) += ResultPtr;
break;
}
}
}
char* X86JITInfo::allocateThreadLocalMemory(size_t size) {
#if defined(X86_32_JIT) && !defined(__APPLE__) && !defined(_MSC_VER)
TLSOffset -= size;
return TLSOffset;
#else
llvm_unreachable("Cannot allocate thread local storage on this arch!");
return 0;
#endif
}
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