diff options
Diffstat (limited to 'lib/ExecutionEngine/JIT/JITMemoryManager.cpp')
| -rw-r--r-- | lib/ExecutionEngine/JIT/JITMemoryManager.cpp | 153 |
1 files changed, 153 insertions, 0 deletions
diff --git a/lib/ExecutionEngine/JIT/JITMemoryManager.cpp b/lib/ExecutionEngine/JIT/JITMemoryManager.cpp index efd570d7c5..d404d0ccdb 100644 --- a/lib/ExecutionEngine/JIT/JITMemoryManager.cpp +++ b/lib/ExecutionEngine/JIT/JITMemoryManager.cpp @@ -314,6 +314,17 @@ namespace { /// should allocate a separate slab. static const size_t DefaultSizeThreshold; + /// getPointerToNamedFunction - This method returns the address of the + /// specified function by using the dlsym function call. As such it is only + /// useful for resolving library symbols, not code generated symbols. + /// + /// If AbortOnFailure is false and no function with the given name is + /// found, this function silently returns a null pointer. Otherwise, + /// it prints a message to stderr and aborts. + /// + virtual void *getPointerToNamedFunction(const std::string &Name, + bool AbortOnFailure = true); + void AllocateGOT(); // Testing methods. @@ -757,6 +768,148 @@ bool DefaultJITMemoryManager::CheckInvariants(std::string &ErrorStr) { return true; } +//===----------------------------------------------------------------------===// +// getPointerToNamedFunction() implementation. +//===----------------------------------------------------------------------===// +#include "llvm/Support/ErrorHandling.h" +#include "llvm/Support/DynamicLibrary.h" +#include "llvm/Config/config.h" + +// AtExitHandlers - List of functions to call when the program exits, +// registered with the atexit() library function. +static std::vector<void (*)()> AtExitHandlers; + +/// runAtExitHandlers - Run any functions registered by the program's +/// calls to atexit(3), which we intercept and store in +/// AtExitHandlers. +/// +static void runAtExitHandlers() { + while (!AtExitHandlers.empty()) { + void (*Fn)() = AtExitHandlers.back(); + AtExitHandlers.pop_back(); + Fn(); + } +} + +//===----------------------------------------------------------------------===// +// Function stubs that are invoked instead of certain library calls +//===----------------------------------------------------------------------===// + +// Force the following functions to be linked in to anything that uses the +// JIT. This is a hack designed to work around the all-too-clever Glibc +// strategy of making these functions work differently when inlined vs. when +// not inlined, and hiding their real definitions in a separate archive file +// that the dynamic linker can't see. For more info, search for +// 'libc_nonshared.a' on Google, or read http://llvm.org/PR274. +#if defined(__linux__) +#if defined(HAVE_SYS_STAT_H) +#include <sys/stat.h> +#endif +#include <fcntl.h> +#include <unistd.h> +/* stat functions are redirecting to __xstat with a version number. On x86-64 + * linking with libc_nonshared.a and -Wl,--export-dynamic doesn't make 'stat' + * available as an exported symbol, so we have to add it explicitly. + */ +namespace { +class StatSymbols { +public: + StatSymbols() { + sys::DynamicLibrary::AddSymbol("stat", (void*)(intptr_t)stat); + sys::DynamicLibrary::AddSymbol("fstat", (void*)(intptr_t)fstat); + sys::DynamicLibrary::AddSymbol("lstat", (void*)(intptr_t)lstat); + sys::DynamicLibrary::AddSymbol("stat64", (void*)(intptr_t)stat64); + sys::DynamicLibrary::AddSymbol("\x1stat64", (void*)(intptr_t)stat64); + sys::DynamicLibrary::AddSymbol("\x1open64", (void*)(intptr_t)open64); + sys::DynamicLibrary::AddSymbol("\x1lseek64", (void*)(intptr_t)lseek64); + sys::DynamicLibrary::AddSymbol("fstat64", (void*)(intptr_t)fstat64); + sys::DynamicLibrary::AddSymbol("lstat64", (void*)(intptr_t)lstat64); + sys::DynamicLibrary::AddSymbol("atexit", (void*)(intptr_t)atexit); + sys::DynamicLibrary::AddSymbol("mknod", (void*)(intptr_t)mknod); + } +}; +} +static StatSymbols initStatSymbols; +#endif // __linux__ + +// jit_exit - Used to intercept the "exit" library call. +static void jit_exit(int Status) { + runAtExitHandlers(); // Run atexit handlers... + exit(Status); +} + +// jit_atexit - Used to intercept the "atexit" library call. +static int jit_atexit(void (*Fn)()) { + AtExitHandlers.push_back(Fn); // Take note of atexit handler... + return 0; // Always successful +} + +static int jit_noop() { + return 0; +} + +//===----------------------------------------------------------------------===// +// +/// getPointerToNamedFunction - This method returns the address of the specified +/// function by using the dynamic loader interface. As such it is only useful +/// for resolving library symbols, not code generated symbols. +/// +void *DefaultJITMemoryManager::getPointerToNamedFunction(const std::string &Name, + bool AbortOnFailure) { + // Check to see if this is one of the functions we want to intercept. Note, + // we cast to intptr_t here to silence a -pedantic warning that complains + // about casting a function pointer to a normal pointer. + if (Name == "exit") return (void*)(intptr_t)&jit_exit; + if (Name == "atexit") return (void*)(intptr_t)&jit_atexit; + + // We should not invoke parent's ctors/dtors from generated main()! + // On Mingw and Cygwin, the symbol __main is resolved to + // callee's(eg. tools/lli) one, to invoke wrong duplicated ctors + // (and register wrong callee's dtors with atexit(3)). + // We expect ExecutionEngine::runStaticConstructorsDestructors() + // is called before ExecutionEngine::runFunctionAsMain() is called. + if (Name == "__main") return (void*)(intptr_t)&jit_noop; + + const char *NameStr = Name.c_str(); + // If this is an asm specifier, skip the sentinal. + if (NameStr[0] == 1) ++NameStr; + + // If it's an external function, look it up in the process image... + void *Ptr = sys::DynamicLibrary::SearchForAddressOfSymbol(NameStr); + if (Ptr) return Ptr; + + // If it wasn't found and if it starts with an underscore ('_') character, + // try again without the underscore. + if (NameStr[0] == '_') { + Ptr = sys::DynamicLibrary::SearchForAddressOfSymbol(NameStr+1); + if (Ptr) return Ptr; + } + + // Darwin/PPC adds $LDBLStub suffixes to various symbols like printf. These + // are references to hidden visibility symbols that dlsym cannot resolve. + // If we have one of these, strip off $LDBLStub and try again. +#if defined(__APPLE__) && defined(__ppc__) + if (Name.size() > 9 && Name[Name.size()-9] == '$' && + memcmp(&Name[Name.size()-8], "LDBLStub", 8) == 0) { + // First try turning $LDBLStub into $LDBL128. If that fails, strip it off. + // This mirrors logic in libSystemStubs.a. + std::string Prefix = std::string(Name.begin(), Name.end()-9); + if (void *Ptr = getPointerToNamedFunction(Prefix+"$LDBL128", false)) + return Ptr; + if (void *Ptr = getPointerToNamedFunction(Prefix, false)) + return Ptr; + } +#endif + + if (AbortOnFailure) { + report_fatal_error("Program used external function '"+Name+ + "' which could not be resolved!"); + } + return 0; +} + + + JITMemoryManager *JITMemoryManager::CreateDefaultMemManager() { return new DefaultJITMemoryManager(); } |