| 1 | #!/usr/bin/env bash
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| 2 | #
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| 3 | # Demonstrate compiler features
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| 4 | #
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| 5 | # Usage:
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| 6 | # demo/c-compiler.sh <function name>
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| 7 |
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| 8 | set -o nounset
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| 9 | set -o pipefail
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| 10 | set -o errexit
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| 11 |
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| 12 | REPO_ROOT=$(cd $(dirname $0)/..; pwd)
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| 13 |
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| 14 | source $REPO_ROOT/build/common.sh
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| 15 |
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| 16 |
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| 17 | # chrome://tracing
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| 18 | # https://aras-p.info/blog/2019/01/16/time-trace-timeline-flame-chart-profiler-for-Clang/
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| 19 | ftime-trace() {
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| 20 | local dir=_tmp/ftime-trace
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| 21 | mkdir -p $dir
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| 22 | rm -f -v $dir/*
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| 23 |
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| 24 | echo ' int foo() { return 32; } ' > $dir/lib.cc
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| 25 | echo ' int main() { return 42; } ' > $dir/main.cc
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| 26 |
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| 27 | #$CLANGXX --version
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| 28 |
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| 29 | # Compiler annoyances:
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| 30 | # - -ftime-trace is IGNORED without -c, which means compile without linking
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| 31 | # - Can't specify -o with multiple source files
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| 32 |
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| 33 | set -x
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| 34 | $CLANGXX -ftime-trace -o $dir/main.o -c $dir/main.cc
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| 35 | $CLANGXX -ftime-trace -o $dir/lib.o -c $dir/lib.cc
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| 36 | set +x
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| 37 | echo
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| 38 |
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| 39 | ls -l $dir
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| 40 | echo
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| 41 |
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| 42 | # .o file is 'relocatable', otherwise it's 'executable'
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| 43 | file $dir/*
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| 44 | echo
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| 45 | }
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| 46 |
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| 47 | preprocessor() {
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| 48 | local dir=_tmp/preprocess
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| 49 | mkdir -p $dir
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| 50 | rm -f -v $dir/*
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| 51 |
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| 52 | echo '
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| 53 | #include <stdio.h>
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| 54 | int foo() { return 32; }
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| 55 | ' > $dir/lib.cc
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| 56 |
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| 57 | # Create a file that gets included twice
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| 58 | {
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| 59 | echo '#ifndef LIB2_H'
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| 60 | echo '#define LIB2_H'
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| 61 |
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| 62 | # ~13K lines
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| 63 | echo '#include <vector>'
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| 64 |
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| 65 | # Almost 32K lines!
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| 66 | #echo '#include <unordered_map>'
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| 67 |
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| 68 | # This doesn't make a difference! The preprocessor strips comments
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| 69 | for i in $(seq 1000); do
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| 70 | echo '// comment'
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| 71 | done
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| 72 |
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| 73 | for i in $(seq 1000); do
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| 74 | echo "int foo$i() { return $i; }"
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| 75 | done
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| 76 |
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| 77 | echo '#endif // LIB2_H'
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| 78 | } > $dir/lib2.h
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| 79 |
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| 80 | echo '
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| 81 | #include <vector>
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| 82 | #include "lib2.h" // transitive include
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| 83 |
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| 84 | inline int bar() { return 1; }
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| 85 | ' > $dir/lib.h
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| 86 |
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| 87 | # wow 12K files for <vector>
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| 88 | echo '
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| 89 | #include <vector>
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| 90 | #include "lib.h"
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| 91 | #include "lib2.h" // duplicate include
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| 92 |
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| 93 | int main() { return 42; }
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| 94 | ' > $dir/main.cc
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| 95 |
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| 96 | $CXX -E $dir/lib.cc > $dir/lib.post.cc
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| 97 |
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| 98 | $CXX -E $dir/main.cc > $dir/main.post.cc
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| 99 |
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| 100 | wc -l $dir/*.post.cc
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| 101 |
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| 102 | # make sure the file compiles
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| 103 | $CXX -o $dir/main $dir/main.cc
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| 104 | }
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| 105 |
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| 106 | duplicate-symbols() {
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| 107 | local dir=_tmp/duplicate-symbols
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| 108 | rm -f -v $dir/*
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| 109 | mkdir -p $dir
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| 110 |
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| 111 | echo '
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| 112 | #include "mycpp/runtime.h"
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| 113 |
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| 114 | GLOBAL_STR(str0, "hi");
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| 115 |
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| 116 | int* g1 = new int[100];
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| 117 |
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| 118 | ' > $dir/lib.cc
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| 119 |
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| 120 | # Why is it OK to link asdl/runtime.cc and _build/cpp/oils-for-unix.cc together?
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| 121 | #
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| 122 | # Oh they are NOT linked together. asdl/runtime.cc is only for tests!
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| 123 |
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| 124 | echo '
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| 125 | #include "mycpp/runtime.h"
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| 126 |
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| 127 | GLOBAL_STR(str0, "hi");
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| 128 |
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| 129 | // int* g1 = new int[100];
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| 130 | int* g2 = new int[100];
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| 131 |
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| 132 | int main() {
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| 133 | printf("hi\n");
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| 134 | }
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| 135 | ' > $dir/main.cc
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| 136 |
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| 137 | local flags='-D GC'
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| 138 | $CXX -I . -o $dir/main $flags $dir/lib.cc $dir/main.cc
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| 139 |
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| 140 | $dir/main
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| 141 | }
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| 142 |
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| 143 | "$@"
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