Changeset 1586

Timestamp:

05/16/10 21:34:48 (3 years ago)

Author:

perry

Message:

Add JITting of BPF bytecode using LLVM

Location:

trunk

Files:

• configure.in (modified) (6 diffs)
• lib/Makefile.am (modified) (4 diffs)
• lib/bpf-jit (added)
• lib/bpf-jit/bpf-jit.cc (added)
• lib/bpf-jit/bpf-jit.h (added)
• lib/bpf-jit/bpf-opcodes.c (added)
• lib/trace.c (modified) (4 diffs)

trunk/configure.in

@@ -55 +55 @@
 if test "$GCC" = "yes"; then
         CFLAGS="$CFLAGS -Wall -Wextra -Wmissing-prototypes -O2"
+        CXXFLAGS="$CXXFLAGS -Wall -Wextra -O2"
 # We assume that gcc knows about -fvisibility and friends, as I can't see
 # a good easy way of testing for it here.
@@ -60 +61 @@
         LIBCFLAGS="$LIBCFLAGS -DLT_BUILDING_DLL=1"
         LIBCFLAGS="$LIBCFLAGS -fvisibility=hidden"
+        LIBCXXFLAGS="$CXXFLAGS"
+        LIBCXXFLAGS="$CXXFLAGS -DLT_BUILDING_DLL=1"
+        LIBCXXFLAGS="$CXXFLAGS -fvisibility=hidden"
 fi
 
@@ -277 +281 @@
 AC_SEARCH_LIBS(mvprintw, ncurses, [], [ AC_MSG_ERROR([NCurses library not available]) ])
 
+AC_ARG_WITH([llvm],
+        [AC_HELP_STRING([--with-llvm],
+                [support Just In Time compiler])],
+        use_llvm="yes",
+        use_llvm="check")
+
+AC_PATH_PROG(llvm_config, llvm-config)
+
+if (test "$use_llvm" != "no"); then
+        AC_PATH_PROG(LLVM_CONFIG, llvm-config, no)
+        if test "$LLVM_CONFIG" = "no" ; then
+                AC_MSG_NOTICE([Unable to find llvm-config.  JIT support disabled.])
+                JIT=no
+        else
+                LIBCXXFLAGS="`$LLVM_CONFIG --cxxflags` $CXXFLAGS"
+                ADD_LIBS="$ADD_LIBS `$LLVM_CONFIG --libs all`";
+                LDFLAGS="`$LLVM_CONFIG --ldflags` $LDFLAGS";
+                JIT=yes
+                AC_DEFINE(HAVE_LLVM, 1, [Set to 1 if you have LLVM installed])
+        fi
+fi
+
+
 AM_CONDITIONAL([HAVE_BPF_CAPTURE], [test "$ac_cv_have_decl_BIOCSETIF" = yes ])
 AM_CONDITIONAL([HAVE_DAG], [test "$libtrace_dag" = true])
@@ -287 +314 @@
 AM_CONDITIONAL([HAVE_NETPACKET_PACKET_H], [test "$libtrace_netpacket_packet_h" = true])
 AM_CONDITIONAL([HAVE_LIBGDC], [test "$ac_cv_header_gdc_h" = yes])
+AM_CONDITIONAL([HAVE_LLVM], [test "x$LLVM_CONFIG" != "xno" ])
 
 # Check for miscellaneous programs
@@ -305 +333 @@
 AC_SUBST([HAVE_BPF_CAPTURE])
 AC_SUBST([HAVE_LIBGDC])
+AC_SUBST([HAVE_LLVM])
 AC_SUBST([LIBCFLAGS])
+AC_SUBST([LIBCXXFLAGS])
 dnl and finally, output our Makefiles
 AC_OUTPUT
@@ -334 +364 @@
         AC_MSG_NOTICE([Compiled with DAG live capture support: No])
 fi
+reportopt "Compiled with LLVM BPF JIT support" $JIT
 reportopt "Building man pages/documentation" $libtrace_doxygen
 

trunk/lib/Makefile.am

@@ -3 +3 @@
 
 AM_CFLAGS=@LIBCFLAGS@
+AM_CXXFLAGS=@LIBCXXFLAGS@
 
 extra_DIST = format_template.c
@@ -46 +47 @@
 EXTRA_DIST=format_dag24.c format_dag25.c
 
+if HAVE_LLVM
+BPFJITSOURCE=bpf-jit/bpf-jit.cc 
+else
+BPFJITSOURCE=
+endif
+
+
 libtrace_la_SOURCES = trace.c common.h \
                 format_erf.c format_pcap.c format_legacy.c \
@@ -56 +64 @@
                 protocols_transport.c protocols.h \
                 $(DAGSOURCE) format_erf.h \
+                $(BPFJITSOURCE) \
                 $(LIBTRACEIO_ZLIB) $(LIBTRACEIO_BZLIB) $(LIBTRACEIO_LZO) \
                 ior-peek.c ior-stdio.c ior-thread.c \
@@ -74 +83 @@
 dagopts.c:
         cp @DAG_TOOLS_DIR@/dagopts.c .
+
+if HAVE_LLVM
+# Rules to build the llvm .cc file from a C description of each opcode.
+bpf-jit/bpf-opcodes.llvm.bc: bpf-jit/bpf-opcodes.c
+        `$(LLVM_CONFIG) --bindir`/llvm-gcc -std=c99 -c -O0 -emit-llvm $< -o $@
+
+bpf-jit/bpf-opcodes.llvm.cc: bpf-jit/bpf-opcodes.llvm.bc
+        `$(LLVM_CONFIG) --bindir`/llc -f -march=cpp -cppgen=module $< -o $@
+
+bpf-jit/bpf-jit.cc: bpf-jit/bpf-opcodes.llvm.cc
+
+EXTRA_DIST+=bpf-jit/bpf-opcodes.c
+BUILT_SOURCES=bpf-jit/bpf-opcodes.llvm.cc
+endif
+CLEANFILES=bpf-jit/bpf-opcodes.llvm.cc bpf-jit/bpf-opcodes.llvm.bc

trunk/lib/trace.c

@@ -1103 +1103 @@
         filter->filter.bf_len = bf_len;
         filter->filterstring = NULL;
+        filter->jitfilter = NULL;
         /* "flag" indicates that the filter member is valid */
         filter->flag = 1; 
@@ -1119 +1120 @@
                                 malloc(sizeof(libtrace_filter_t));
         filter->filterstring = strdup(filterstring);
+        filter->jitfilter = NULL;
         filter->flag = 0;
         return filter;
@@ -1133 +1135 @@
         if (filter->flag)
                 pcap_freecode(&filter->filter);
+#ifdef HAVE_LLVM
+        if (filter->jitfilter) 
+                destroy_program(filter->jitfilter);
+#endif
         free(filter);
 #else
@@ -1257 +1263 @@
         }
 
+        /* If we're jitting, we may need to JIT the BPF code now too */
+#if HAVE_LLVM
+        if (!filter->jitfilter) {
+                filter->jitfilter = compile_program(filter->filter.bf_insns, filter->filter.bf_len);
+        }
+#endif
+
         assert(filter->flag);
+        /* Now execute the filter */
+#if HAVE_LLVM
+        ret=filter->jitfilter->bpf_run((unsigned char *)linkptr, clen);
+#else
         ret=bpf_filter(filter->filter.bf_insns,(u_char*)linkptr,(unsigned int)clen,(unsigned int)clen);
+#endif
 
         /* If we copied the packet earlier, make sure that we free it */