#!/bin/bash
# Copyright 2021 The Fuchsia Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

#### CATEGORY=Diagnostic
### Dumps disassembly for binaries from the build.

## usage: fx dis [-l | -S | -n] BINARY...
##
## Dump disassembly for a binary to a file in the build directory.
##
##   -l                        list source locations interleaved with assembly
##   -S                        list source code lines interleaved with assembly
##   -r                        list relocations interleaved with assembly
##   -n                        do not demangle symbol names
##   -L                        use llvm-objdump rather than GNU objdump
##
## Each BINARY can be the name of the binary file without directory, e.g.
## "libzircon.so" or "zircon.elf"; or the name of a GN target, e.g. "zircon";
## or a string of (lowercase) hex characters that's an ELF build ID.
##
## The disassembly will be written to a file next to the binary file in
## the build directory, using its name with ".lst" suffix.

set -o errexit

source "$(cd "$(dirname "${BASH_SOURCE[0]}")" >/dev/null 2>&1 && pwd)"/../lib/vars.sh || exit $?
fx-config-read

readonly BINARIES_JSON="$FUCHSIA_BUILD_DIR/binaries.json"

DEMANGLE=true
USE_LLVM=false
OBJDUMP_ARGS=()

while getopts lSrLn OPT; do
  case $OPT in
  [lSr]) OBJDUMP_ARGS+=(-$OPT) ;;
  L) USE_LLVM=true ;;
  n) DEMANGLE=false ;;
  esac
done
shift $((OPTIND-1))

if $DEMANGLE; then
  OBJDUMP_ARGS+=(--demangle)
fi

if [[ $# -eq 0 ]]; then
  fx-command-help
  exit 1
fi

run_jq() {
  fx-command-run jq --raw-output "$@"
}

run_direct_filter() {
  run_jq "$1" "$BINARIES_JSON"
}

normalize_build_ids() {
  local query='
.[] | select(.elf_build_id) | "\(.elf_build_id) \(.cpu) \(.debug) \(.label)"'
  run_jq "$query" "$BINARIES_JSON" | normalize_build_ids_filter
}

normalize_build_ids_filter() {
  echo '['
  local comma=
  while read id cpu debug label; do
    echo "$comma{\
\"build_id\": \"$(<"$FUCHSIA_BUILD_DIR/$id")\",\
\"cpu\": \"$cpu\",\
\"debug\": \"$debug\",\
\"label\": \"$label\"\
}"
    comma=','
  done
  echo ']'
}

run_buildid_filter() {
  normalize_build_ids | run_jq "$1"
}

is_hex() {
  local str="$1"
  if [[ -z "$str" ]]; then
    return 0
  fi
  while [[ -n "$str" ]]; do
    case "${str:0:1}" in
      [0-9a-f]) ;;
      *) return 1 ;;
    esac
    str="${str:1}"
  done
  return 0
}

RUN_FILTER=run_direct_filter
for BINARY in "$@"; do
  if is_hex "$BINARY"; then
    RUN_FILTER=run_buildid_filter
    break
  fi
done

FILTER=".[] | select(false"

for BINARY in "$@"; do
  if is_hex "$BINARY"; then
    FILTER+=" or (.build_id == \"$BINARY\")"
  else
    DEBUG_RE="(^|/)$BINARY([.]debug)?\$"
    LABEL_RE=":$BINARY[(]"
    FILTER+=" or (.debug | test(\"$DEBUG_RE\")) or (.label | test(\"$LABEL_RE\"))"
  fi
done

FILTER+=') | "\(.cpu) \(.debug) \(.label)"'

PATHS=($($RUN_FILTER "$FILTER"))

if (( ${#PATHS[@]} == 0 )); then
  fx-error "No binaries matched any of: $*"
  exit 1
fi

disassemble() {
  local BINARY_CPU="$1" BINARY_PATH="$2" BINARY_LABEL="$3"
  local -a CMD

  if $USE_LLVM; then
    CMD=("$PREBUILT_CLANG_DIR/bin/llvm-objdump")
  else
    case "$BINARY_CPU" in
    arm64) CMD=("$PREBUILT_GCC_DIR/bin/aarch64-elf-objdump" -m aarch64) ;;
    x64) CMD=("$PREBUILT_GCC_DIR/bin/x86_64-elf-objdump" -m i386:x86-64) ;;
    *)
      fx-error "Can't handle binary $BINARY_PATH with CPU type $BINARY_CPU"
      exit 1
      ;;
    esac
  fi

  CMD+=(-d)

  "${CMD[@]}" "${OBJDUMP_ARGS[@]}" "$FUCHSIA_BUILD_DIR/$BINARY_PATH" > "$FUCHSIA_BUILD_DIR/${BINARY_PATH}.lst"
  fx-info Wrote "${BINARY_PATH}.lst" for "$BINARY_LABEL"
}

i=0
while (( i < ${#PATHS[@]} )); do
  disassemble "${PATHS[$i]}" "${PATHS[$((i+1))]}" "${PATHS[$((i+2))]}"
  ((i+=3))
done