Inside Bitcoin

1#!/usr/bin/env bash
2
3export LC_ALL=C.UTF-8
4set -Eeuo pipefail
5
6# Declare paths to libraries
7declare -A LIBS
8LIBS[cli]="libbitcoin_cli.a"
9LIBS[common]="libbitcoin_common.a"
10LIBS[consensus]="libbitcoin_consensus.a"
11LIBS[crypto]="libbitcoin_crypto.a"
12LIBS[node]="libbitcoin_node.a"
13LIBS[util]="libbitcoin_util.a"
14LIBS[wallet]="libbitcoin_wallet.a"
15
16# Declare allowed dependencies "X Y" where X is allowed to depend on Y. This
17# list is taken from doc/design/libraries.md.
18ALLOWED_DEPENDENCIES=(
19    "cli common"
20    "cli util"
21    "common consensus"
22    "common crypto"
23    "common util"
24    "consensus crypto"
25    "node common"
26    "node consensus"
27    "node crypto"
28    "node kernel"
29    "node util"
30    "util crypto"
31    "wallet common"
32    "wallet crypto"
33    "wallet util"
34)
35
36# Add minor dependencies omitted from doc/design/libraries.md to keep the
37# dependency diagram simple.
38ALLOWED_DEPENDENCIES+=(
39    "wallet consensus"
40)
41
42# Declare list of known errors that should be suppressed.
43declare -A SUPPRESS
44# init/common.cpp file calls InitError and InitWarning from interface_ui which
45# is currently part of the node library. interface_ui should just be part of the
46# common library instead, and is moved in
47# https://github.com/bitcoin/bitcoin/issues/10102
48SUPPRESS["common.cpp.o interface_ui.cpp.o _Z11InitWarningRK13bilingual_str"]=1
49SUPPRESS["common.cpp.o interface_ui.cpp.o _Z9InitErrorRK13bilingual_str"]=1
50
51usage() {
52   echo "Usage: $(basename "${BASH_SOURCE[0]}") [BUILD_DIR]"
53}
54
55# Output makefile targets, converting library .a paths to CMake targets
56lib_targets() {
57  for lib in "${!LIBS[@]}"; do
58      for lib_path in ${LIBS[$lib]}; do
59          local name="${lib_path##*/}"
60          name="${name#lib}"
61          name="${name%.a}"
62          echo "$name"
63      done
64  done
65}
66
67# Extract symbol names and object names and write to text files
68extract_symbols() {
69    local temp_dir="$1"
70    for lib in "${!LIBS[@]}"; do
71        for lib_path in ${LIBS[$lib]}; do
72            nm -o "$lib_path" | { grep ' T \| W ' || true; } | awk '{print $3, $1}' >> "${temp_dir}/${lib}_exports.txt"
73            nm -o "$lib_path" | { grep ' U ' || true; } | awk '{print $3, $1}' >> "${temp_dir}/${lib}_imports.txt"
74            awk '{print $1}' "${temp_dir}/${lib}_exports.txt" | sort -u > "${temp_dir}/${lib}_exported_symbols.txt"
75            awk '{print $1}' "${temp_dir}/${lib}_imports.txt" | sort -u > "${temp_dir}/${lib}_imported_symbols.txt"
76        done
77    done
78}
79
80# Lookup object name(s) corresponding to symbol name in text file
81obj_names() {
82    local symbol="$1"
83    local txt_file="$2"
84    sed -n "s/^$symbol [^:]\\+:\\([^:]\\+\\):[^:]*\$/\\1/p" "$txt_file" | sort -u
85}
86
87# Iterate through libraries and find disallowed dependencies
88check_libraries() {
89    local temp_dir="$1"
90    local result=0
91    for src in "${!LIBS[@]}"; do
92        for dst in "${!LIBS[@]}"; do
93            if [ "$src" != "$dst" ] && ! is_allowed "$src" "$dst"; then
94                if ! check_disallowed "$src" "$dst" "$temp_dir"; then
95                    result=1
96                fi
97            fi
98        done
99    done
100    check_not_suppressed
101    return $result
102}
103
104# Return whether src library is allowed to depend on dst.
105is_allowed() {
106    local src="$1"
107    local dst="$2"
108    for allowed in "${ALLOWED_DEPENDENCIES[@]}"; do
109        if [ "$src $dst" = "$allowed" ]; then
110            return 0
111        fi
112    done
113    return 1
114}
115
116# Return whether src library imports any symbols from dst, assuming src is not
117# allowed to depend on dst.
118check_disallowed() {
119    local src="$1"
120    local dst="$2"
121    local temp_dir="$3"
122    local result=0
123
124    # Loop over symbol names exported by dst and imported by src
125    while read symbol; do
126        local dst_obj
127        dst_obj=$(obj_names "$symbol" "${temp_dir}/${dst}_exports.txt")
128        while read src_obj; do
129            if ! check_suppress "$src_obj" "$dst_obj" "$symbol"; then
130                echo "Error: $src_obj depends on $dst_obj symbol '$(c++filt "$symbol")', can suppress with:"
131                echo "    SUPPRESS[\"$src_obj $dst_obj $symbol\"]=1"
132                result=1
133            fi
134        done < <(obj_names "$symbol" "${temp_dir}/${src}_imports.txt")
135    done < <(comm -12 "${temp_dir}/${dst}_exported_symbols.txt" "${temp_dir}/${src}_imported_symbols.txt")
136    return $result
137}
138
139# Declare array to track errors which were suppressed.
140declare -A SUPPRESSED
141
142# Return whether error should be suppressed and record suppression in
143# SUPPRESSED array.
144check_suppress() {
145    local src_obj="$1"
146    local dst_obj="$2"
147    local symbol="$3"
148    for suppress in "${!SUPPRESS[@]}"; do
149        read suppress_src suppress_dst suppress_pattern <<<"$suppress"
150        if [[ "$src_obj" == "$suppress_src" && "$dst_obj" == "$suppress_dst" && "$symbol" =~ $suppress_pattern ]]; then
151            SUPPRESSED["$suppress"]=1
152            return 0
153        fi
154    done
155    return 1
156}
157
158# Warn about error which were supposed to be suppressed, but were not encountered.
159check_not_suppressed() {
160    for suppress in "${!SUPPRESS[@]}"; do
161        if [[ ! -v SUPPRESSED[$suppress] ]]; then
162            echo >&2 "Warning: suppression '$suppress' was ignored, consider deleting."
163        fi
164    done
165}
166
167# Check arguments.
168if [ "$#" = 0 ]; then
169    BUILD_DIR="$(dirname "${BASH_SOURCE[0]}")/../../build"
170elif [ "$#" = 1 ]; then
171    BUILD_DIR="$1"
172else
173    echo >&2 "Error: wrong number of arguments."
174    usage >&2
175    exit 1
176fi
177if [ ! -f "$BUILD_DIR/Makefile" ]; then
178    echo >&2 "Error: directory '$BUILD_DIR' does not contain a makefile, please specify path to build directory for library targets."
179    usage >&2
180    exit 1
181fi
182
183# Build libraries and run checks.
184# shellcheck disable=SC2046
185cmake --build "$BUILD_DIR" -j"$(nproc)" -t $(lib_targets)
186TEMP_DIR="$(mktemp -d)"
187cd "$BUILD_DIR/lib"
188extract_symbols "$TEMP_DIR"
189if check_libraries "$TEMP_DIR"; then
190    echo "Success! No unexpected dependencies were detected."
191    RET=0
192else
193    echo >&2 "Error: Unexpected dependencies were detected. Check previous output."
194    RET=1
195fi
196rm -r "$TEMP_DIR"
197exit $RET
198