1 files changed, 610 insertions, 0 deletions

diff --git a/tools/perf/util/genelf_debug.c b/tools/perf/util/genelf_debug.c
new file mode 100644
index 000000000000..5980f7d256b1
--- /dev/null
+++ b/tools/perf/util/genelf_debug.c
@@ -0,0 +1,610 @@
+/*
+ * genelf_debug.c
+ * Copyright (C) 2015, Google, Inc
+ *
+ * Contributed by:
+ *      Stephane Eranian <eranian@google.com>
+ *
+ * Released under the GPL v2.
+ *
+ * based on GPLv2 source code from Oprofile
+ * @remark Copyright 2007 OProfile authors
+ * @author Philippe Elie
+ */
+#include <sys/types.h>
+#include <stdio.h>
+#include <getopt.h>
+#include <stddef.h>
+#include <libelf.h>
+#include <string.h>
+#include <stdlib.h>
+#include <inttypes.h>
+#include <limits.h>
+#include <fcntl.h>
+#include <err.h>
+#include <dwarf.h>
+
+#include "perf.h"
+#include "genelf.h"
+#include "../util/jitdump.h"
+
+#define BUFFER_EXT_DFL_SIZE     (4 * 1024)
+
+typedef uint32_t uword;
+typedef uint16_t uhalf;
+typedef int32_t  sword;
+typedef int16_t  shalf;
+typedef uint8_t  ubyte;
+typedef int8_t   sbyte;
+
+struct buffer_ext {
+        size_t cur_pos;
+        size_t max_sz;
+        void *data;
+};
+
+static void
+buffer_ext_dump(struct buffer_ext *be, const char *msg)
+{
+        size_t i;
+        warnx("DUMP for %s", msg);
+        for (i = 0 ; i < be->cur_pos; i++)
+                warnx("%4zu 0x%02x", i, (((char *)be->data)[i]) & 0xff);
+}
+
+static inline int
+buffer_ext_add(struct buffer_ext *be, void *addr, size_t sz)
+{
+        void *tmp;
+        size_t be_sz = be->max_sz;
+
+retry:
+        if ((be->cur_pos + sz) < be_sz) {
+                memcpy(be->data + be->cur_pos, addr, sz);
+                be->cur_pos += sz;
+                return 0;
+        }
+
+        if (!be_sz)
+                be_sz = BUFFER_EXT_DFL_SIZE;
+        else
+                be_sz <<= 1;
+
+        tmp = realloc(be->data, be_sz);
+        if (!tmp)
+                return -1;
+
+        be->data   = tmp;
+        be->max_sz = be_sz;
+
+        goto retry;
+}
+
+static void
+buffer_ext_init(struct buffer_ext *be)
+{
+        be->data = NULL;
+        be->cur_pos = 0;
+        be->max_sz = 0;
+}
+
+static inline size_t
+buffer_ext_size(struct buffer_ext *be)
+{
+        return be->cur_pos;
+}
+
+static inline void *
+buffer_ext_addr(struct buffer_ext *be)
+{
+        return be->data;
+}
+
+struct debug_line_header {
+        // Not counting this field
+        uword total_length;
+        // version number (2 currently)
+        uhalf version;
+        // relative offset from next field to
+        // program statement
+        uword prolog_length;
+        ubyte minimum_instruction_length;
+        ubyte default_is_stmt;
+        // line_base - see DWARF 2 specs
+        sbyte line_base;
+        // line_range - see DWARF 2 specs
+        ubyte line_range;
+        // number of opcode + 1
+        ubyte opcode_base;
+        /* follow the array of opcode args nr: ubytes [nr_opcode_base] */
+        /* follow the search directories index, zero terminated string
+         * terminated by an empty string.
+         */
+        /* follow an array of { filename, LEB128, LEB128, LEB128 }, first is
+         * the directory index entry, 0 means current directory, then mtime
+         * and filesize, last entry is followed by en empty string.
+         */
+        /* follow the first program statement */
+} __attribute__((packed));
+
+/* DWARF 2 spec talk only about one possible compilation unit header while
+ * binutils can handle two flavours of dwarf 2, 32 and 64 bits, this is not
+ * related to the used arch, an ELF 32 can hold more than 4 Go of debug
+ * information. For now we handle only DWARF 2 32 bits comp unit. It'll only
+ * become a problem if we generate more than 4GB of debug information.
+ */
+struct compilation_unit_header {
+        uword total_length;
+        uhalf version;
+        uword debug_abbrev_offset;
+        ubyte pointer_size;
+} __attribute__((packed));
+
+#define DW_LNS_num_opcode (DW_LNS_set_isa + 1)
+
+/* field filled at run time are marked with -1 */
+static struct debug_line_header const default_debug_line_header = {
+        .total_length = -1,
+        .version = 2,
+        .prolog_length = -1,
+        .minimum_instruction_length = 1,        /* could be better when min instruction size != 1 */
+        .default_is_stmt = 1,   /* we don't take care about basic block */
+        .line_base = -5,        /* sensible value for line base ... */
+        .line_range = -14,     /* ... and line range are guessed statically */
+        .opcode_base = DW_LNS_num_opcode
+};
+
+static ubyte standard_opcode_length[] =
+{
+        0, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 1
+};
+#if 0
+{
+        [DW_LNS_advance_pc]   = 1,
+        [DW_LNS_advance_line] = 1,
+        [DW_LNS_set_file] =  1,
+        [DW_LNS_set_column] = 1,
+        [DW_LNS_fixed_advance_pc] = 1,
+        [DW_LNS_set_isa] = 1,
+};
+#endif
+
+/* field filled at run time are marked with -1 */
+static struct compilation_unit_header default_comp_unit_header = {
+        .total_length = -1,
+        .version = 2,
+        .debug_abbrev_offset = 0,     /* we reuse the same abbrev entries for all comp unit */
+        .pointer_size = sizeof(void *)
+};
+
+static void emit_uword(struct buffer_ext *be, uword data)
+{
+        buffer_ext_add(be, &data, sizeof(uword));
+}
+
+static void emit_string(struct buffer_ext *be, const char *s)
+{
+        buffer_ext_add(be, (void *)s, strlen(s) + 1);
+}
+
+static void emit_unsigned_LEB128(struct buffer_ext *be,
+                                 unsigned long data)
+{
+        do {
+                ubyte cur = data & 0x7F;
+                data >>= 7;
+                if (data)
+                        cur |= 0x80;
+                buffer_ext_add(be, &cur, 1);
+        } while (data);
+}
+
+static void emit_signed_LEB128(struct buffer_ext *be, long data)
+{
+        int more = 1;
+        int negative = data < 0;
+        int size = sizeof(long) * CHAR_BIT;
+        while (more) {
+                ubyte cur = data & 0x7F;
+                data >>= 7;
+                if (negative)
+                        data |= - (1 << (size - 7));
+                if ((data == 0 && !(cur & 0x40)) ||
+                    (data == -1l && (cur & 0x40)))
+                        more = 0;
+                else
+                        cur |= 0x80;
+                buffer_ext_add(be, &cur, 1);
+        }
+}
+
+static void emit_extended_opcode(struct buffer_ext *be, ubyte opcode,
+                                 void *data, size_t data_len)
+{
+        buffer_ext_add(be, (char *)"", 1);
+
+        emit_unsigned_LEB128(be, data_len + 1);
+
+        buffer_ext_add(be, &opcode, 1);
+        buffer_ext_add(be, data, data_len);
+}
+
+static void emit_opcode(struct buffer_ext *be, ubyte opcode)
+{
+        buffer_ext_add(be, &opcode, 1);
+}
+
+static void emit_opcode_signed(struct buffer_ext  *be,
+                               ubyte opcode, long data)
+{
+        buffer_ext_add(be, &opcode, 1);
+        emit_signed_LEB128(be, data);
+}
+
+static void emit_opcode_unsigned(struct buffer_ext *be, ubyte opcode,
+                                 unsigned long data)
+{
+        buffer_ext_add(be, &opcode, 1);
+        emit_unsigned_LEB128(be, data);
+}
+
+static void emit_advance_pc(struct buffer_ext *be, unsigned long delta_pc)
+{
+        emit_opcode_unsigned(be, DW_LNS_advance_pc, delta_pc);
+}
+
+static void emit_advance_lineno(struct buffer_ext  *be, long delta_lineno)
+{
+        emit_opcode_signed(be, DW_LNS_advance_line, delta_lineno);
+}
+
+static void emit_lne_end_of_sequence(struct buffer_ext *be)
+{
+        emit_extended_opcode(be, DW_LNE_end_sequence, NULL, 0);
+}
+
+static void emit_set_file(struct buffer_ext *be, unsigned long idx)
+{
+        emit_opcode_unsigned(be, DW_LNS_set_file, idx);
+}
+
+static void emit_lne_define_filename(struct buffer_ext *be,
+                                     const char *filename)
+{
+        buffer_ext_add(be, (void *)"", 1);
+
+        /* LNE field, strlen(filename) + zero termination, 3 bytes for: the dir entry, timestamp, filesize */
+        emit_unsigned_LEB128(be, strlen(filename) + 5);
+        emit_opcode(be, DW_LNE_define_file);
+        emit_string(be, filename);
+        /* directory index 0=do not know */
+        emit_unsigned_LEB128(be, 0);
+        /* last modification date on file 0=do not know */
+        emit_unsigned_LEB128(be, 0);
+        /* filesize 0=do not know */
+        emit_unsigned_LEB128(be, 0);
+}
+
+static void emit_lne_set_address(struct buffer_ext *be,
+                                 void *address)
+{
+        emit_extended_opcode(be, DW_LNE_set_address, &address, sizeof(unsigned long));
+}
+
+static ubyte get_special_opcode(struct debug_entry *ent,
+                                unsigned int last_line,
+                                unsigned long last_vma)
+{
+        unsigned int temp;
+        unsigned long delta_addr;
+
+        /*
+         * delta from line_base
+         */
+        temp = (ent->lineno - last_line) - default_debug_line_header.line_base;
+
+        if (temp >= default_debug_line_header.line_range)
+                return 0;
+
+        /*
+         * delta of addresses
+         */
+        delta_addr = (ent->addr - last_vma) / default_debug_line_header.minimum_instruction_length;
+
+        /* This is not sufficient to ensure opcode will be in [0-256] but
+         * sufficient to ensure when summing with the delta lineno we will
+         * not overflow the unsigned long opcode */
+
+        if (delta_addr <= 256 / default_debug_line_header.line_range) {
+                unsigned long opcode = temp +
+                        (delta_addr * default_debug_line_header.line_range) +
+                        default_debug_line_header.opcode_base;
+
+                return opcode <= 255 ? opcode : 0;
+        }
+        return 0;
+}
+
+static void emit_lineno_info(struct buffer_ext *be,
+                             struct debug_entry *ent, size_t nr_entry,
+                             unsigned long code_addr)
+{
+        size_t i;
+
+        /*
+         * Machine state at start of a statement program
+         * address = 0
+         * file    = 1
+         * line    = 1
+         * column  = 0
+         * is_stmt = default_is_stmt as given in the debug_line_header
+         * basic block = 0
+         * end sequence = 0
+         */
+
+        /* start state of the state machine we take care of */
+        unsigned long last_vma = code_addr;
+        char const  *cur_filename = NULL;
+        unsigned long cur_file_idx = 0;
+        int last_line = 1;
+
+        emit_lne_set_address(be, (void *)code_addr);
+
+        for (i = 0; i < nr_entry; i++, ent = debug_entry_next(ent)) {
+                int need_copy = 0;
+                ubyte special_opcode;
+
+                /*
+                 * check if filename changed, if so add it
+                 */
+                if (!cur_filename || strcmp(cur_filename, ent->name)) {
+                        emit_lne_define_filename(be, ent->name);
+                        cur_filename = ent->name;
+                        emit_set_file(be, ++cur_file_idx);
+                        need_copy = 1;
+                }
+
+                special_opcode = get_special_opcode(ent, last_line, last_vma);
+                if (special_opcode != 0) {
+                        last_line = ent->lineno;
+                        last_vma  = ent->addr;
+                        emit_opcode(be, special_opcode);
+                } else {
+                        /*
+                         * lines differ, emit line delta
+                         */
+                        if (last_line != ent->lineno) {
+                                emit_advance_lineno(be, ent->lineno - last_line);
+                                last_line = ent->lineno;
+                                need_copy = 1;
+                        }
+                        /*
+                         * addresses differ, emit address delta
+                         */
+                        if (last_vma != ent->addr) {
+                                emit_advance_pc(be, ent->addr - last_vma);
+                                last_vma = ent->addr;
+                                need_copy = 1;
+                        }
+                        /*
+                         * add new row to matrix
+                         */
+                        if (need_copy)
+                                emit_opcode(be, DW_LNS_copy);
+                }
+        }
+}
+
+static void add_debug_line(struct buffer_ext *be,
+        struct debug_entry *ent, size_t nr_entry,
+        unsigned long code_addr)
+{
+        struct debug_line_header * dbg_header;
+        size_t old_size;
+
+        old_size = buffer_ext_size(be);
+
+        buffer_ext_add(be, (void *)&default_debug_line_header,
+                 sizeof(default_debug_line_header));
+
+        buffer_ext_add(be, &standard_opcode_length,  sizeof(standard_opcode_length));
+
+        // empty directory entry
+        buffer_ext_add(be, (void *)"", 1);
+
+        // empty filename directory
+        buffer_ext_add(be, (void *)"", 1);
+
+        dbg_header = buffer_ext_addr(be) + old_size;
+        dbg_header->prolog_length = (buffer_ext_size(be) - old_size) -
+                offsetof(struct debug_line_header, minimum_instruction_length);
+
+        emit_lineno_info(be, ent, nr_entry, code_addr);
+
+        emit_lne_end_of_sequence(be);
+
+        dbg_header = buffer_ext_addr(be) + old_size;
+        dbg_header->total_length = (buffer_ext_size(be) - old_size) -
+                offsetof(struct debug_line_header, version);
+}
+
+static void
+add_debug_abbrev(struct buffer_ext *be)
+{
+        emit_unsigned_LEB128(be, 1);
+        emit_unsigned_LEB128(be, DW_TAG_compile_unit);
+        emit_unsigned_LEB128(be, DW_CHILDREN_yes);
+        emit_unsigned_LEB128(be, DW_AT_stmt_list);
+        emit_unsigned_LEB128(be, DW_FORM_data4);
+        emit_unsigned_LEB128(be, 0);
+        emit_unsigned_LEB128(be, 0);
+        emit_unsigned_LEB128(be, 0);
+}
+
+static void
+add_compilation_unit(struct buffer_ext *be,
+                     size_t offset_debug_line)
+{
+        struct compilation_unit_header *comp_unit_header;
+        size_t old_size = buffer_ext_size(be);
+
+        buffer_ext_add(be, &default_comp_unit_header,
+                       sizeof(default_comp_unit_header));
+
+        emit_unsigned_LEB128(be, 1);
+        emit_uword(be, offset_debug_line);
+
+        comp_unit_header = buffer_ext_addr(be) + old_size;
+        comp_unit_header->total_length = (buffer_ext_size(be) - old_size) -
+                offsetof(struct compilation_unit_header, version);
+}
+
+static int
+jit_process_debug_info(uint64_t code_addr,
+                       void *debug, int nr_debug_entries,
+                       struct buffer_ext *dl,
+                       struct buffer_ext *da,
+                       struct buffer_ext *di)
+{
+        struct debug_entry *ent = debug;
+        int i;
+
+        for (i = 0; i < nr_debug_entries; i++) {
+                ent->addr = ent->addr - code_addr;
+                ent = debug_entry_next(ent);
+        }
+        add_compilation_unit(di, buffer_ext_size(dl));
+        add_debug_line(dl, debug, nr_debug_entries, 0);
+        add_debug_abbrev(da);
+        if (0) buffer_ext_dump(da, "abbrev");
+
+        return 0;
+}
+
+int
+jit_add_debug_info(Elf *e, uint64_t code_addr, void *debug, int nr_debug_entries)
+{
+        Elf_Data *d;
+        Elf_Scn *scn;
+        Elf_Shdr *shdr;
+        struct buffer_ext dl, di, da;
+        int ret;
+
+        buffer_ext_init(&dl);
+        buffer_ext_init(&di);
+        buffer_ext_init(&da);
+
+        ret = jit_process_debug_info(code_addr, debug, nr_debug_entries, &dl, &da, &di);
+        if (ret)
+                return -1;
+        /*
+         * setup .debug_line section
+         */
+        scn = elf_newscn(e);
+        if (!scn) {
+                warnx("cannot create section");
+                return -1;
+        }
+
+        d = elf_newdata(scn);
+        if (!d) {
+                warnx("cannot get new data");
+                return -1;
+        }
+
+        d->d_align = 1;
+        d->d_off = 0LL;
+        d->d_buf = buffer_ext_addr(&dl);
+        d->d_type = ELF_T_BYTE;
+        d->d_size = buffer_ext_size(&dl);
+        d->d_version = EV_CURRENT;
+
+        shdr = elf_getshdr(scn);
+        if (!shdr) {
+                warnx("cannot get section header");
+                return -1;
+        }
+
+        shdr->sh_name = 52; /* .debug_line */
+        shdr->sh_type = SHT_PROGBITS;
+        shdr->sh_addr = 0; /* must be zero or == sh_offset -> dynamic object */
+        shdr->sh_flags = 0;
+        shdr->sh_entsize = 0;
+
+        /*
+         * setup .debug_info section
+         */
+        scn = elf_newscn(e);
+        if (!scn) {
+                warnx("cannot create section");
+                return -1;
+        }
+
+        d = elf_newdata(scn);
+        if (!d) {
+                warnx("cannot get new data");
+                return -1;
+        }
+
+        d->d_align = 1;
+        d->d_off = 0LL;
+        d->d_buf = buffer_ext_addr(&di);
+        d->d_type = ELF_T_BYTE;
+        d->d_size = buffer_ext_size(&di);
+        d->d_version = EV_CURRENT;
+
+        shdr = elf_getshdr(scn);
+        if (!shdr) {
+                warnx("cannot get section header");
+                return -1;
+        }
+
+        shdr->sh_name = 64; /* .debug_info */
+        shdr->sh_type = SHT_PROGBITS;
+        shdr->sh_addr = 0; /* must be zero or == sh_offset -> dynamic object */
+        shdr->sh_flags = 0;
+        shdr->sh_entsize = 0;
+
+        /*
+         * setup .debug_abbrev section
+         */
+        scn = elf_newscn(e);
+        if (!scn) {
+                warnx("cannot create section");
+                return -1;
+        }
+
+        d = elf_newdata(scn);
+        if (!d) {
+                warnx("cannot get new data");
+                return -1;
+        }
+
+        d->d_align = 1;
+        d->d_off = 0LL;
+        d->d_buf = buffer_ext_addr(&da);
+        d->d_type = ELF_T_BYTE;
+        d->d_size = buffer_ext_size(&da);
+        d->d_version = EV_CURRENT;
+
+        shdr = elf_getshdr(scn);
+        if (!shdr) {
+                warnx("cannot get section header");
+                return -1;
+        }
+
+        shdr->sh_name = 76; /* .debug_info */
+        shdr->sh_type = SHT_PROGBITS;
+        shdr->sh_addr = 0; /* must be zero or == sh_offset -> dynamic object */
+        shdr->sh_flags = 0;
+        shdr->sh_entsize = 0;
+
+        /*
+         * now we update the ELF image with all the sections
+         */
+        if (elf_update(e, ELF_C_WRITE) < 0) {
+                warnx("elf_update debug failed");
+                return -1;
+        }
+        return 0;
+}