df7c69952b
Summary: Memory reads using the ptrace API need to be executed on a designated thread and in 4-byte increments. The process_vm_read syscall has no such requirements and it is about 50 times faster. This patch makes lldb-server use the faster API if the target kernel supports it. Kernel support for this feature is determined at runtime. Using process_vm_writev in the same manner is more complicated since this syscall (unlike ptrace) respects page protection settings and so it cannot be used to set a breakpoint, since code pages are typically read-only. However, memory writes are not currently a performance bottleneck as they happen much more rarely. Test Plan: all tests continue to pass Reviewers: ovyalov, vharron Subscribers: tberghammer, lldb-commits Differential Revision: http://reviews.llvm.org/D10488 llvm-svn: 239924
50 lines
1.2 KiB
C++
50 lines
1.2 KiB
C++
//===-- LibcGlue.cpp --------------------------------------------*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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// This files adds functions missing from libc on earlier versions of Android
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#include <android/api-level.h>
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#include <sys/syscall.h>
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#include <lldb/Host/linux/Uio.h>
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#if __ANDROID_API__ < 21
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <signal.h>
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#include "lldb/Host/Time.h"
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time_t timegm(struct tm* t)
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{
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return (time_t) timegm64(t);
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}
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int signalfd (int fd, const sigset_t *mask, int flags)
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{
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return syscall(__NR_signalfd4, fd, mask, _NSIG / 8, flags);
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}
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int posix_openpt(int flags)
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{
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return open("/dev/ptmx", flags);
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}
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#endif
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ssize_t process_vm_readv(::pid_t pid,
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const struct iovec *local_iov, unsigned long liovcnt,
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const struct iovec *remote_iov, unsigned long riovcnt,
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unsigned long flags)
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{
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return syscall(__NR_process_vm_readv, pid, local_iov, liovcnt, remote_iov, riovcnt, flags);
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}
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