From ca58d7e64bdfc54f7dfe46713c1e2acc68d7522d Mon Sep 17 00:00:00 2001 From: Ben Gainey Date: Wed, 22 Nov 2017 18:25:41 -0600 Subject: [PATCH] perf jvmti: Generate correct debug information for inlined code tools/perf/jvmti is broken in so far as it generates incorrect debug information. Specifically it attributes all debug lines to the original method being output even in the case that some code is being inlined from elsewhere. This patch fixes the issue. To test (from within linux/tools/perf): export JDIR=/usr/lib/jvm/java-8-openjdk-amd64/ make cat << __EOF > Test.java public class Test { private StringBuilder b = new StringBuilder(); private void loop(int i, String... args) { for (String a : args) b.append(a); long hc = b.hashCode() * System.nanoTime(); b = new StringBuilder(); b.append(hc); System.out.printf("Iteration %d = %d\n", i, hc); } public void run(String... args) { for (int i = 0; i < 10000; ++i) { loop(i, args); } } public static void main(String... args) { Test t = new Test(); t.run(args); } } __EOF $JDIR/bin/javac Test.java ./perf record -F 10000 -g -k mono $JDIR/bin/java -agentpath:`pwd`/libperf-jvmti.so Test ./perf inject --jit -i perf.data -o perf.data.jitted ./perf annotate -i perf.data.jitted --stdio | grep Test\.java: | sort -u Before this patch, Test.java line numbers get reported that are greater than the number of lines in the Test.java file. They come from the source file of the inlined function, e.g. java/lang/String.java:1085. For further validation one can examine those lines in the JDK source distribution and confirm that they map to inlined functions called by Test.java. After this patch, the filename of the inlined function is output rather than the incorrect original source filename. Signed-off-by: Ben Gainey Tested-by: Arnaldo Carvalho de Melo Tested-by: Stephane Eranian Cc: Alexander Shishkin Cc: Ben Gainey Cc: Colin King Cc: Darren Hart Cc: Jiri Olsa Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Thomas Gleixner Fixes: 598b7c6919c7 ("perf jit: add source line info support") Link: http://lkml.kernel.org/r/20171122182541.d25599a3eb1ada3480d142fa@arm.com Signed-off-by: Kim Phillips Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/jvmti/jvmti_agent.c | 16 +++-- tools/perf/jvmti/jvmti_agent.h | 7 +- tools/perf/jvmti/libjvmti.c | 147 ++++++++++++++++++++++++++++++++++------- 3 files changed, 134 insertions(+), 36 deletions(-) diff --git a/tools/perf/jvmti/jvmti_agent.c b/tools/perf/jvmti/jvmti_agent.c index cf36de7..0c6d100 100644 --- a/tools/perf/jvmti/jvmti_agent.c +++ b/tools/perf/jvmti/jvmti_agent.c @@ -384,13 +384,13 @@ jvmti_write_code(void *agent, char const *sym, } int -jvmti_write_debug_info(void *agent, uint64_t code, const char *file, - jvmti_line_info_t *li, int nr_lines) +jvmti_write_debug_info(void *agent, uint64_t code, + int nr_lines, jvmti_line_info_t *li, + const char * const * file_names) { struct jr_code_debug_info rec; - size_t sret, len, size, flen; + size_t sret, len, size, flen = 0; uint64_t addr; - const char *fn = file; FILE *fp = agent; int i; @@ -405,7 +405,9 @@ jvmti_write_debug_info(void *agent, uint64_t code, const char *file, return -1; } - flen = strlen(file) + 1; + for (i = 0; i < nr_lines; ++i) { + flen += strlen(file_names[i]) + 1; + } rec.p.id = JIT_CODE_DEBUG_INFO; size = sizeof(rec); @@ -421,7 +423,7 @@ jvmti_write_debug_info(void *agent, uint64_t code, const char *file, * file[] : source file name */ size += nr_lines * sizeof(struct debug_entry); - size += flen * nr_lines; + size += flen; rec.p.total_size = size; /* @@ -452,7 +454,7 @@ jvmti_write_debug_info(void *agent, uint64_t code, const char *file, if (sret != 1) goto error; - sret = fwrite_unlocked(fn, flen, 1, fp); + sret = fwrite_unlocked(file_names[i], strlen(file_names[i]) + 1, 1, fp); if (sret != 1) goto error; } diff --git a/tools/perf/jvmti/jvmti_agent.h b/tools/perf/jvmti/jvmti_agent.h index fe32d83..6ed82f6 100644 --- a/tools/perf/jvmti/jvmti_agent.h +++ b/tools/perf/jvmti/jvmti_agent.h @@ -14,6 +14,7 @@ typedef struct { unsigned long pc; int line_number; int discrim; /* discriminator -- 0 for now */ + jmethodID methodID; } jvmti_line_info_t; void *jvmti_open(void); @@ -22,11 +23,9 @@ int jvmti_write_code(void *agent, char const *symbol_name, uint64_t vma, void const *code, const unsigned int code_size); -int jvmti_write_debug_info(void *agent, - uint64_t code, - const char *file, +int jvmti_write_debug_info(void *agent, uint64_t code, int nr_lines, jvmti_line_info_t *li, - int nr_lines); + const char * const * file_names); #if defined(__cplusplus) } diff --git a/tools/perf/jvmti/libjvmti.c b/tools/perf/jvmti/libjvmti.c index c62c9fc..6add3e9 100644 --- a/tools/perf/jvmti/libjvmti.c +++ b/tools/perf/jvmti/libjvmti.c @@ -47,6 +47,7 @@ do_get_line_numbers(jvmtiEnv *jvmti, void *pc, jmethodID m, jint bci, tab[lines].pc = (unsigned long)pc; tab[lines].line_number = loc_tab[i].line_number; tab[lines].discrim = 0; /* not yet used */ + tab[lines].methodID = m; lines++; } else { break; @@ -125,6 +126,99 @@ get_line_numbers(jvmtiEnv *jvmti, const void *compile_info, jvmti_line_info_t ** return JVMTI_ERROR_NONE; } +static void +copy_class_filename(const char * class_sign, const char * file_name, char * result, size_t max_length) +{ + /* + * Assume path name is class hierarchy, this is a common practice with Java programs + */ + if (*class_sign == 'L') { + int j, i = 0; + char *p = strrchr(class_sign, '/'); + if (p) { + /* drop the 'L' prefix and copy up to the final '/' */ + for (i = 0; i < (p - class_sign); i++) + result[i] = class_sign[i+1]; + } + /* + * append file name, we use loops and not string ops to avoid modifying + * class_sign which is used later for the symbol name + */ + for (j = 0; i < (max_length - 1) && file_name && j < strlen(file_name); j++, i++) + result[i] = file_name[j]; + + result[i] = '\0'; + } else { + /* fallback case */ + size_t file_name_len = strlen(file_name); + strncpy(result, file_name, file_name_len < max_length ? file_name_len : max_length); + } +} + +static jvmtiError +get_source_filename(jvmtiEnv *jvmti, jmethodID methodID, char ** buffer) +{ + jvmtiError ret; + jclass decl_class; + char *file_name = NULL; + char *class_sign = NULL; + char fn[PATH_MAX]; + size_t len; + + ret = (*jvmti)->GetMethodDeclaringClass(jvmti, methodID, &decl_class); + if (ret != JVMTI_ERROR_NONE) { + print_error(jvmti, "GetMethodDeclaringClass", ret); + return ret; + } + + ret = (*jvmti)->GetSourceFileName(jvmti, decl_class, &file_name); + if (ret != JVMTI_ERROR_NONE) { + print_error(jvmti, "GetSourceFileName", ret); + return ret; + } + + ret = (*jvmti)->GetClassSignature(jvmti, decl_class, &class_sign, NULL); + if (ret != JVMTI_ERROR_NONE) { + print_error(jvmti, "GetClassSignature", ret); + goto free_file_name_error; + } + + copy_class_filename(class_sign, file_name, fn, PATH_MAX); + len = strlen(fn); + *buffer = malloc((len + 1) * sizeof(char)); + if (!*buffer) { + print_error(jvmti, "GetClassSignature", ret); + ret = JVMTI_ERROR_OUT_OF_MEMORY; + goto free_class_sign_error; + } + strcpy(*buffer, fn); + ret = JVMTI_ERROR_NONE; + +free_class_sign_error: + (*jvmti)->Deallocate(jvmti, (unsigned char *)class_sign); +free_file_name_error: + (*jvmti)->Deallocate(jvmti, (unsigned char *)file_name); + + return ret; +} + +static jvmtiError +fill_source_filenames(jvmtiEnv *jvmti, int nr_lines, + const jvmti_line_info_t * line_tab, + char ** file_names) +{ + int index; + jvmtiError ret; + + for (index = 0; index < nr_lines; ++index) { + ret = get_source_filename(jvmti, line_tab[index].methodID, &(file_names[index])); + if (ret != JVMTI_ERROR_NONE) + return ret; + } + + return JVMTI_ERROR_NONE; +} + static void JNICALL compiled_method_load_cb(jvmtiEnv *jvmti, jmethodID method, @@ -135,16 +229,18 @@ compiled_method_load_cb(jvmtiEnv *jvmti, const void *compile_info) { jvmti_line_info_t *line_tab = NULL; + char ** line_file_names = NULL; jclass decl_class; char *class_sign = NULL; char *func_name = NULL; char *func_sign = NULL; - char *file_name= NULL; + char *file_name = NULL; char fn[PATH_MAX]; uint64_t addr = (uint64_t)(uintptr_t)code_addr; jvmtiError ret; int nr_lines = 0; /* in line_tab[] */ size_t len; + int output_debug_info = 0; ret = (*jvmti)->GetMethodDeclaringClass(jvmti, method, &decl_class); @@ -158,6 +254,19 @@ compiled_method_load_cb(jvmtiEnv *jvmti, if (ret != JVMTI_ERROR_NONE) { warnx("jvmti: cannot get line table for method"); nr_lines = 0; + } else if (nr_lines > 0) { + line_file_names = malloc(sizeof(char*) * nr_lines); + if (!line_file_names) { + warnx("jvmti: cannot allocate space for line table method names"); + } else { + memset(line_file_names, 0, sizeof(char*) * nr_lines); + ret = fill_source_filenames(jvmti, nr_lines, line_tab, line_file_names); + if (ret != JVMTI_ERROR_NONE) { + warnx("jvmti: fill_source_filenames failed"); + } else { + output_debug_info = 1; + } + } } } @@ -181,33 +290,14 @@ compiled_method_load_cb(jvmtiEnv *jvmti, goto error; } - /* - * Assume path name is class hierarchy, this is a common practice with Java programs - */ - if (*class_sign == 'L') { - int j, i = 0; - char *p = strrchr(class_sign, '/'); - if (p) { - /* drop the 'L' prefix and copy up to the final '/' */ - for (i = 0; i < (p - class_sign); i++) - fn[i] = class_sign[i+1]; - } - /* - * append file name, we use loops and not string ops to avoid modifying - * class_sign which is used later for the symbol name - */ - for (j = 0; i < (PATH_MAX - 1) && file_name && j < strlen(file_name); j++, i++) - fn[i] = file_name[j]; - fn[i] = '\0'; - } else { - /* fallback case */ - strcpy(fn, file_name); - } + copy_class_filename(class_sign, file_name, fn, PATH_MAX); + /* * write source line info record if we have it */ - if (jvmti_write_debug_info(jvmti_agent, addr, fn, line_tab, nr_lines)) - warnx("jvmti: write_debug_info() failed"); + if (output_debug_info) + if (jvmti_write_debug_info(jvmti_agent, addr, nr_lines, line_tab, (const char * const *) line_file_names)) + warnx("jvmti: write_debug_info() failed"); len = strlen(func_name) + strlen(class_sign) + strlen(func_sign) + 2; { @@ -223,6 +313,13 @@ error: (*jvmti)->Deallocate(jvmti, (unsigned char *)class_sign); (*jvmti)->Deallocate(jvmti, (unsigned char *)file_name); free(line_tab); + while (line_file_names && (nr_lines > 0)) { + if (line_file_names[nr_lines - 1]) { + free(line_file_names[nr_lines - 1]); + } + nr_lines -= 1; + } + free(line_file_names); } static void JNICALL -- 2.7.4