diff options
Diffstat (limited to 'upb/pb/compile_decoder_x64.c')
| -rw-r--r-- | upb/pb/compile_decoder_x64.c | 336 |
1 files changed, 176 insertions, 160 deletions
diff --git a/upb/pb/compile_decoder_x64.c b/upb/pb/compile_decoder_x64.c index 51b9b9e..3ce11e4 100644 --- a/upb/pb/compile_decoder_x64.c +++ b/upb/pb/compile_decoder_x64.c @@ -7,7 +7,7 @@ * Driver code for the x64 JIT compiler. */ -// Needed to ensure we get defines like MAP_ANON. +/* Needed to ensure we get defines like MAP_ANON. */ #define _GNU_SOURCE #include <dlfcn.h> @@ -19,50 +19,50 @@ #include "upb/pb/varint.int.h" #include "upb/shim/shim.h" -// To debug the JIT: -// -// 1. Uncomment: -// #define UPB_JIT_LOAD_SO -// -// Note: this mode requires that we can shell out to gcc. -// -// 2. Run the test locally. This will load the JIT code by building a -// .so (/tmp/upb-jit-code.so) and using dlopen, so more of the tooling will -// work properly (like GDB). -// -// IF YOU ALSO WANT AUTOMATIC JIT DEBUG OUTPUT: -// -// 3. Run: upb/pb/make-gdb-script.rb > script.gdb. This reads -// /tmp/upb-jit-code.so as input and generates a GDB script that is specific -// to this jit code. -// -// 4. Run: gdb --command=script.gdb --args path/to/test -// This will drop you to a GDB prompt which you can now use normally. -// But when you run the test it will print a message to stdout every time -// the JIT executes assembly for a particular bytecode. Sample output: -// -// X.enterjit bytes=18 -// buf_ofs=1 data_rem=17 delim_rem=-2 X.0x6.OP_PARSE_DOUBLE -// buf_ofs=9 data_rem=9 delim_rem=-10 X.0x7.OP_CHECKDELIM -// buf_ofs=9 data_rem=9 delim_rem=-10 X.0x8.OP_TAG1 -// X.0x3.dispatch.DecoderTest -// X.parse_unknown -// X.0x3.dispatch.DecoderTest -// X.decode_unknown_tag_fallback -// X.exitjit -// -// This output should roughly correspond to the output that the bytecode -// interpreter emits when compiled with UPB_DUMP_BYTECODE (modulo some -// extra JIT-specific output). - -// These defines are necessary for DynASM codegen. -// See dynasm/dasm_proto.h for more info. +/* To debug the JIT: + * + * 1. Uncomment: + * #define UPB_JIT_LOAD_SO + * + * Note: this mode requires that we can shell out to gcc. + * + * 2. Run the test locally. This will load the JIT code by building a + * .so (/tmp/upb-jit-code.so) and using dlopen, so more of the tooling will + * work properly (like GDB). + * + * IF YOU ALSO WANT AUTOMATIC JIT DEBUG OUTPUT: + * + * 3. Run: upb/pb/make-gdb-script.rb > script.gdb. This reads + * /tmp/upb-jit-code.so as input and generates a GDB script that is specific + * to this jit code. + * + * 4. Run: gdb --command=script.gdb --args path/to/test + * This will drop you to a GDB prompt which you can now use normally. + * But when you run the test it will print a message to stdout every time + * the JIT executes assembly for a particular bytecode. Sample output: + * + * X.enterjit bytes=18 + * buf_ofs=1 data_rem=17 delim_rem=-2 X.0x6.OP_PARSE_DOUBLE + * buf_ofs=9 data_rem=9 delim_rem=-10 X.0x7.OP_CHECKDELIM + * buf_ofs=9 data_rem=9 delim_rem=-10 X.0x8.OP_TAG1 + * X.0x3.dispatch.DecoderTest + * X.parse_unknown + * X.0x3.dispatch.DecoderTest + * X.decode_unknown_tag_fallback + * X.exitjit + * + * This output should roughly correspond to the output that the bytecode + * interpreter emits when compiled with UPB_DUMP_BYTECODE (modulo some + * extra JIT-specific output). */ + +/* These defines are necessary for DynASM codegen. + * See dynasm/dasm_proto.h for more info. */ #define Dst_DECL jitcompiler *jc #define Dst_REF (jc->dynasm) #define Dst (jc) -// In debug mode, make DynASM do internal checks (must be defined before any -// dasm header is included. +/* In debug mode, make DynASM do internal checks (must be defined before any + * dasm header is included. */ #ifndef NDEBUG #define DASM_CHECKS #endif @@ -75,49 +75,49 @@ typedef struct { mgroup *group; uint32_t *pc; - // This pointer is allocated by dasm_init() and freed by dasm_free(). + /* This pointer is allocated by dasm_init() and freed by dasm_free(). */ struct dasm_State *dynasm; - // Maps some key (an arbitrary void*) to a pclabel. - // - // The pclabel represents a location in the generated code -- DynASM exposes - // a pclabel -> (machine code offset) lookup function. - // - // The key can be anything. There are two main kinds of keys: - // - bytecode location -- the void* points to the bytecode instruction - // itself. We can then use this to generate jumps to this instruction. - // - other object (like dispatch table). We use these to represent parts - // of the generated code that do not exactly correspond to a bytecode - // instruction. - upb_inttable jmptargets; + /* Maps some key (an arbitrary void*) to a pclabel. + * + * The pclabel represents a location in the generated code -- DynASM exposes + * a pclabel -> (machine code offset) lookup function. + * + * The key can be anything. There are two main kinds of keys: + * - bytecode location -- the void* points to the bytecode instruction + * itself. We can then use this to generate jumps to this instruction. + * - other object (like dispatch table). We use these to represent parts + * of the generated code that do not exactly correspond to a bytecode + * instruction. */ + upb_inttable jmptargets; #ifndef NDEBUG - // Like jmptargets, but members are present in the table when they have had - // define_jmptarget() (as opposed to jmptarget) called. Used to verify that - // define_jmptarget() is called exactly once for every target. - // The value is ignored. + /* Like jmptargets, but members are present in the table when they have had + * define_jmptarget() (as opposed to jmptarget) called. Used to verify that + * define_jmptarget() is called exactly once for every target. + * The value is ignored. */ upb_inttable jmpdefined; - // For checking that two asmlabels aren't defined for the same byte. + /* For checking that two asmlabels aren't defined for the same byte. */ int lastlabelofs; #endif #ifdef UPB_JIT_LOAD_SO - // For marking labels that should go into the generated code. - // Maps pclabel -> char* label (string is owned by the table). + /* For marking labels that should go into the generated code. + * Maps pclabel -> char* label (string is owned by the table). */ upb_inttable asmlabels; #endif - // The total number of pclabels currently defined. - // Note that this contains both jmptargets and asmlabels, which both use - // pclabels but for different purposes. + /* The total number of pclabels currently defined. + * Note that this contains both jmptargets and asmlabels, which both use + * pclabels but for different purposes. */ uint32_t pclabel_count; - // Used by DynASM to store globals. + /* Used by DynASM to store globals. */ void **globals; } jitcompiler; -// Functions called by codegen. +/* Functions called by codegen. */ static int jmptarget(jitcompiler *jc, const void *key); static int define_jmptarget(jitcompiler *jc, const void *key); static void asmlabel(jitcompiler *jc, const char *fmt, ...); @@ -174,21 +174,21 @@ static void freejitcompiler(jitcompiler *jc) { #ifdef UPB_JIT_LOAD_SO -// Like sprintf except allocates the string, which is returned and owned by the -// caller. -// -// Like the GNU extension asprintf(), except we abort on error (since this is -// only for debugging). +/* Like sprintf except allocates the string, which is returned and owned by the + * caller. + * + * Like the GNU extension asprintf(), except we abort on error (since this is + * only for debugging). */ static char *upb_vasprintf(const char *fmt, va_list args) { - // Run once to get the length of the string. + /* Run once to get the length of the string. */ va_list args_copy; va_copy(args_copy, args); - int len = vsnprintf(NULL, 0, fmt, args_copy); + int len = _upb_vsnprintf(NULL, 0, fmt, args_copy); va_end(args_copy); - char *ret = malloc(len + 1); // + 1 for NULL terminator. + char *ret = malloc(len + 1); /* + 1 for NULL terminator. */ if (!ret) abort(); - int written = vsnprintf(ret, len + 1, fmt, args); + int written = _upb_vsnprintf(ret, len + 1, fmt, args); UPB_ASSERT_VAR(written, written == len); return ret; @@ -220,23 +220,26 @@ static bool try_getjmptarget(jitcompiler *jc, const void *key, int *pclabel) { } } -// Gets the pclabel for this bytecode location's jmptarget. Requires that the -// jmptarget() has been previously defined. +/* Gets the pclabel for this bytecode location's jmptarget. Requires that the + * jmptarget() has been previously defined. */ static int getjmptarget(jitcompiler *jc, const void *key) { int pclabel = 0; + bool ok; + assert(upb_inttable_lookupptr(&jc->jmpdefined, key, NULL)); - bool ok = try_getjmptarget(jc, key, &pclabel); + ok = try_getjmptarget(jc, key, &pclabel); UPB_ASSERT_VAR(ok, ok); return pclabel; } -// Returns a pclabel that serves as a jmp target for the given bytecode pointer. -// This should only be called for code that is jumping to the target; code -// defining the target should use define_jmptarget(). -// -// Creates/allocates a pclabel for this target if one does not exist already. +/* Returns a pclabel that serves as a jmp target for the given bytecode pointer. + * This should only be called for code that is jumping to the target; code + * defining the target should use define_jmptarget(). + * + * Creates/allocates a pclabel for this target if one does not exist already. */ static int jmptarget(jitcompiler *jc, const void *key) { - int pclabel; + // Optimizer sometimes can't figure out that initializing this is unnecessary. + int pclabel = 0; if (!try_getjmptarget(jc, key, &pclabel)) { pclabel = alloc_pclabel(jc); upb_inttable_insertptr(&jc->jmptargets, key, upb_value_uint32(pclabel)); @@ -244,12 +247,12 @@ static int jmptarget(jitcompiler *jc, const void *key) { return pclabel; } -// Defines a pclabel associated with the given bytecode location. -// Must be called exactly once by the code that is generating the code for this -// bytecode. -// -// Must be called exactly once before bytecode generation is complete (this is a -// sanity check to make sure the label is defined exactly once). +/* Defines a pclabel associated with the given bytecode location. + * Must be called exactly once by the code that is generating the code for this + * bytecode. + * + * Must be called exactly once before bytecode generation is complete (this is a + * sanity check to make sure the label is defined exactly once). */ static int define_jmptarget(jitcompiler *jc, const void *key) { #ifndef NDEBUG upb_inttable_insertptr(&jc->jmpdefined, key, upb_value_bool(true)); @@ -257,115 +260,121 @@ static int define_jmptarget(jitcompiler *jc, const void *key) { return jmptarget(jc, key); } -// Returns a bytecode pc offset relative to the beginning of the group's code. +/* Returns a bytecode pc offset relative to the beginning of the group's + * code. */ static int pcofs(jitcompiler *jc) { return jc->pc - jc->group->bytecode; } -// Returns a machine code offset corresponding to the given key. -// Requires that this key was defined with define_jmptarget. +/* Returns a machine code offset corresponding to the given key. + * Requires that this key was defined with define_jmptarget. */ static int machine_code_ofs(jitcompiler *jc, const void *key) { int pclabel = getjmptarget(jc, key); - // Despite its name, this function takes a pclabel and returns the - // corresponding machine code offset. + /* Despite its name, this function takes a pclabel and returns the + * corresponding machine code offset. */ return dasm_getpclabel(jc, pclabel); } -// Returns a machine code offset corresponding to the given method-relative -// bytecode offset. Note that the bytecode offset is relative to the given -// method, but the returned machine code offset is relative to the beginning of -// *all* the machine code. +/* Returns a machine code offset corresponding to the given method-relative + * bytecode offset. Note that the bytecode offset is relative to the given + * method, but the returned machine code offset is relative to the beginning of + * *all* the machine code. */ static int machine_code_ofs2(jitcompiler *jc, const upb_pbdecodermethod *method, int pcofs) { void *bc_target = jc->group->bytecode + method->code_base.ofs + pcofs; return machine_code_ofs(jc, bc_target); } -// Given a pcofs relative to this method's base, returns a machine code offset -// relative to jmptarget(dispatch->array) (which is used in jitdispatch as the -// machine code base for dispatch table lookups). +/* Given a pcofs relative to this method's base, returns a machine code offset + * relative to jmptarget(dispatch->array) (which is used in jitdispatch as the + * machine code base for dispatch table lookups). */ uint32_t dispatchofs(jitcompiler *jc, const upb_pbdecodermethod *method, int pcofs) { int mc_base = machine_code_ofs(jc, method->dispatch.array); int mc_target = machine_code_ofs2(jc, method, pcofs); + int ret; + assert(mc_base > 0); assert(mc_target > 0); - int ret = mc_target - mc_base; + ret = mc_target - mc_base; assert(ret > 0); return ret; } -// Rewrites the dispatch tables into machine code offsets. +/* Rewrites the dispatch tables into machine code offsets. */ static void patchdispatch(jitcompiler *jc) { upb_inttable_iter i; upb_inttable_begin(&i, &jc->group->methods); for (; !upb_inttable_done(&i); upb_inttable_next(&i)) { upb_pbdecodermethod *method = upb_value_getptr(upb_inttable_iter_value(&i)); - method->is_native_ = true; - upb_inttable *dispatch = &method->dispatch; + upb_inttable_iter i2; + + method->is_native_ = true; - // Remove DISPATCH_ENDMSG -- only the bytecode interpreter needs it. - // And leaving it around will cause us to find field 0 improperly. + /* Remove DISPATCH_ENDMSG -- only the bytecode interpreter needs it. + * And leaving it around will cause us to find field 0 improperly. */ upb_inttable_remove(dispatch, DISPATCH_ENDMSG, NULL); - upb_inttable_iter i2; upb_inttable_begin(&i2, dispatch); for (; !upb_inttable_done(&i2); upb_inttable_next(&i2)) { uintptr_t key = upb_inttable_iter_key(&i2); uint64_t val = upb_value_getuint64(upb_inttable_iter_value(&i2)); uint64_t newval; + bool ok; if (key <= UPB_MAX_FIELDNUMBER) { - // Primary slot. + /* Primary slot. */ uint64_t ofs; uint8_t wt1; uint8_t wt2; upb_pbdecoder_unpackdispatch(val, &ofs, &wt1, &wt2); - // Update offset and repack. + /* Update offset and repack. */ ofs = dispatchofs(jc, method, ofs); newval = upb_pbdecoder_packdispatch(ofs, wt1, wt2); assert((int64_t)newval > 0); } else { - // Secondary slot. Since we have 64 bits for the value, we use an - // absolute offset. + /* Secondary slot. Since we have 64 bits for the value, we use an + * absolute offset. */ int mcofs = machine_code_ofs2(jc, method, val); newval = (uint64_t)((char*)jc->group->jit_code + mcofs); } - bool ok = upb_inttable_replace(dispatch, key, upb_value_uint64(newval)); + ok = upb_inttable_replace(dispatch, key, upb_value_uint64(newval)); UPB_ASSERT_VAR(ok, ok); } - // Update entry point for this method to point at mc base instead of bc - // base. Set this only *after* we have patched the offsets - // (machine_code_ofs2() uses this). + /* Update entry point for this method to point at mc base instead of bc + * base. Set this only *after* we have patched the offsets + * (machine_code_ofs2() uses this). */ method->code_base.ptr = (char*)jc->group->jit_code + machine_code_ofs(jc, method); - upb_byteshandler *h = &method->input_handler_; - upb_byteshandler_setstartstr(h, upb_pbdecoder_startjit, NULL); - upb_byteshandler_setstring(h, jc->group->jit_code, method->code_base.ptr); - upb_byteshandler_setendstr(h, upb_pbdecoder_end, method); + { + upb_byteshandler *h = &method->input_handler_; + upb_byteshandler_setstartstr(h, upb_pbdecoder_startjit, NULL); + upb_byteshandler_setstring(h, jc->group->jit_code, method->code_base.ptr); + upb_byteshandler_setendstr(h, upb_pbdecoder_end, method); + } } } #ifdef UPB_JIT_LOAD_SO static void load_so(jitcompiler *jc) { - // Dump to a .so file in /tmp and load that, so all the tooling works right - // (for example, debuggers and profilers will see symbol names for the JIT-ted - // code). This is the same goal of the GDB JIT code below, but the GDB JIT - // interface is only used/understood by GDB. Hopefully a standard will - // develop for registering JIT-ted code that all tools will recognize, - // rendering this obsolete. - - // jc->asmlabels maps: - // pclabel -> char* label - // - // Use this to build mclabels, which maps: - // machine code offset -> char* label - // - // Then we can use mclabels to emit the labels as we iterate over the bytes we - // are outputting. + /* Dump to a .so file in /tmp and load that, so all the tooling works right + * (for example, debuggers and profilers will see symbol names for the JIT-ted + * code). This is the same goal of the GDB JIT code below, but the GDB JIT + * interface is only used/understood by GDB. Hopefully a standard will + * develop for registering JIT-ted code that all tools will recognize, + * rendering this obsolete. + * + * jc->asmlabels maps: + * pclabel -> char* label + * + * Use this to build mclabels, which maps: + * machine code offset -> char* label + * + * Then we can use mclabels to emit the labels as we iterate over the bytes we + * are outputting. */ upb_inttable_iter i; upb_inttable mclabels; upb_inttable_init(&mclabels, UPB_CTYPE_PTR); @@ -376,25 +385,26 @@ static void load_so(jitcompiler *jc) { upb_inttable_iter_value(&i)); } - // We write a .s file in text format, as input to the assembler. - // Then we run gcc to turn it into a .so file. - // - // The last "XXXXXX" will be replaced with something randomly generated by - // mkstmemp(). We don't add ".s" to this filename because it makes the string - // processing for mkstemp() and system() more complicated. + /* We write a .s file in text format, as input to the assembler. + * Then we run gcc to turn it into a .so file. + * + * The last "XXXXXX" will be replaced with something randomly generated by + * mkstmemp(). We don't add ".s" to this filename because it makes the string + * processing for mkstemp() and system() more complicated. */ char s_filename[] = "/tmp/upb-jit-codeXXXXXX"; int fd = mkstemp(s_filename); FILE *f; if (fd >= 0 && (f = fdopen(fd, "wb")) != NULL) { uint8_t *jit_code = (uint8_t*)jc->group->jit_code; - fputs(" .text\n\n", f); size_t linelen = 0; - for (size_t i = 0; i < jc->group->jit_size; i++) { + size_t i; + fputs(" .text\n\n", f); + for (i = 0; i < jc->group->jit_size; i++) { upb_value v; if (upb_inttable_lookup(&mclabels, i, &v)) { const char *label = upb_value_getptr(v); - // "X." makes our JIT syms recognizable as such, which we build into - // other tooling. + /* "X." makes our JIT syms recognizable as such, which we build into + * other tooling. */ fprintf(f, "\n\nX.%s:\n", label); fprintf(f, " .globl X.%s", label); linelen = 1000; @@ -412,10 +422,10 @@ static void load_so(jitcompiler *jc) { abort(); } - // This is exploitable if you have an adversary on your machine who can write - // to this tmp directory. But this is just for debugging so we don't worry - // too much about that. It shouldn't be prone to races against concurrent - // (non-adversarial) upb JIT's because we used mkstemp(). + /* This is exploitable if you have an adversary on your machine who can write + * to this tmp directory. But this is just for debugging so we don't worry + * too much about that. It shouldn't be prone to races against concurrent + * (non-adversarial) upb JIT's because we used mkstemp(). */ char *cmd = upb_asprintf("gcc -shared -o %s.so -x assembler %s", s_filename, s_filename); if (system(cmd) != 0) { @@ -426,12 +436,14 @@ static void load_so(jitcompiler *jc) { char *so_filename = upb_asprintf("%s.so", s_filename); - // Some convenience symlinks. - // This is racy, but just for convenience. + /* Some convenience symlinks. + * This is racy, but just for convenience. */ + int ret; unlink("/tmp/upb-jit-code.so"); unlink("/tmp/upb-jit-code.s"); - symlink(s_filename, "/tmp/upb-jit-code.s"); - symlink(so_filename, "/tmp/upb-jit-code.so"); + ret = symlink(s_filename, "/tmp/upb-jit-code.s"); + ret = symlink(so_filename, "/tmp/upb-jit-code.so"); + UPB_UNUSED(ret); // We don't care if this fails. jc->group->dl = dlopen(so_filename, RTLD_LAZY); free(so_filename); @@ -453,22 +465,26 @@ static void load_so(jitcompiler *jc) { #endif void upb_pbdecoder_jit(mgroup *group) { + jitcompiler *jc; + char *jit_code; + int dasm_status; + group->debug_info = NULL; group->dl = NULL; assert(group->bytecode); - jitcompiler *jc = newjitcompiler(group); + jc = newjitcompiler(group); emit_static_asm(jc); jitbytecode(jc); - int dasm_status = dasm_link(jc, &jc->group->jit_size); + dasm_status = dasm_link(jc, &jc->group->jit_size); if (dasm_status != DASM_S_OK) { fprintf(stderr, "DynASM error; returned status: 0x%08x\n", dasm_status); abort(); } - char *jit_code = mmap(NULL, jc->group->jit_size, PROT_READ | PROT_WRITE, - MAP_ANONYMOUS | MAP_PRIVATE, 0, 0); + jit_code = mmap(NULL, jc->group->jit_size, PROT_READ | PROT_WRITE, + MAP_ANONYMOUS | MAP_PRIVATE, 0, 0); dasm_encode(jc, jit_code); mprotect(jit_code, jc->group->jit_size, PROT_EXEC | PROT_READ); jc->group->jit_code = (upb_string_handlerfunc *)jit_code; @@ -481,7 +497,7 @@ void upb_pbdecoder_jit(mgroup *group) { freejitcompiler(jc); - // Now the bytecode is no longer needed. + /* Now the bytecode is no longer needed. */ free(group->bytecode); group->bytecode = NULL; } @@ -493,7 +509,7 @@ void upb_pbdecoder_freejit(mgroup *group) { dlclose(group->dl); #endif } else { - munmap(group->jit_code, group->jit_size); + munmap((void*)group->jit_code, group->jit_size); } free(group->debug_info); } |