我如何使用错误点来隔离代码传递？
How can I use bugpoint to isolate code passes?
我有一个 LLVM IR 源文件，当我优化它时它会改变行为。我想知道是哪个 LLVM pass 造成的。
这是预期的行为，标准输入中的数字因式分解：
$ wget https://gist.githubusercontent.com/Wilfred/dde83b701d9bb8d7207a/raw/3eea89526ded7efa995f5bda89012b526dd49691/with_zeroing.ll
$ echo 1337 | lli with_zeroing.ll
1337: 7 191
在运行到opt之后，只是呼应原来的数字：
$ opt -S -O2 with_zeroing.ll -o with_zeroing_o2.ll
$ echo 1337 | lli with_zeroing_o2.ll
1337: 1337
如何使用 bugpoint 计算出哪个优化过程正在改变这种行为？
我试过 bugpoint with_zeroing.ll -llc-safe 但我想我需要一种将输入管道输入到生成的编译二进制文件中的方法。
LLVM 错误报告文档 has a great section on optimisation bugs。
首先，在您的代码中找出 opt 正在 运行 的通行证：
$ opt -O2 -debug-pass=Arguments with_zeroing.ll -disable-output
Pass Arguments: -tti -no-aa -tbaa -scoped-noalias -assumption-cache-tracker -targetlibinfo -basicaa -verify -simplifycfg -domtree -sroa -early-cse -lower-expect
Pass Arguments: -targetlibinfo -tti -no-aa -tbaa -scoped-noalias -assumption-cache-tracker -basicaa -ipsccp -globalopt -deadargelim -domtree -instcombine -simplifycfg -basiccg -prune-eh -inline-cost -inline -functionattrs -domtree -sroa -early-cse -lazy-value-info -jump-threading -correlated-propagation -simplifycfg -domtree -instcombine -tailcallelim -simplifycfg -reassociate -domtree -loops -loop-simplify -lcssa -loop-rotate -licm -loop-unswitch -instcombine -scalar-evolution -loop-simplify -lcssa -indvars -loop-idiom -loop-deletion -loop-unroll -mldst-motion -domtree -memdep -gvn -memdep -memcpyopt -sccp -domtree -bdce -instcombine -lazy-value-info -jump-threading -correlated-propagation -domtree -memdep -dse -loops -loop-simplify -lcssa -licm -adce -simplifycfg -domtree -instcombine -barrier -float2int -domtree -loops -loop-simplify -lcssa -loop-rotate -branch-prob -block-freq -scalar-evolution -loop-accesses -loop-vectorize -instcombine -scalar-evolution -slp-vectorizer -simplifycfg -domtree -instcombine -loops -loop-simplify -lcssa -scalar-evolution -loop-unroll -instcombine -loop-simplify -lcssa -licm -scalar-evolution -alignment-from-assumptions -strip-dead-prototypes -elim-avail-extern -globaldce -constmerge -verify
接下来，使用 -input 调用错误点以指定程序的输入：
$ echo "1337" > input.txt
$ bugpoint with_zeroing.ll -input input.txt -run-int \
-targetlibinfo -tti -no-aa -tbaa -scoped-noalias -assumption-cache-tracker -basicaa -ipsccp -globalopt -deadargelim -domtree -instcombine -simplifycfg -basiccg -prune-eh -inline-cost -inline -functionattrs -domtree -sroa -early-cse -lazy-value-info -jump-threading -correlated-propagation -simplifycfg -domtree -instcombine -tailcallelim -simplifycfg -reassociate -domtree -loops -loop-simplify -lcssa -loop-rotate -licm -loop-unswitch -instcombine -scalar-evolution -loop-simplify -lcssa -indvars -loop-idiom -loop-deletion -loop-unroll -mldst-motion -domtree -memdep -gvn -memdep -memcpyopt -sccp -domtree -bdce -instcombine -lazy-value-info -jump-threading -correlated-propagation -domtree -memdep -dse -loops -loop-simplify -lcssa -licm -adce -simplifycfg -domtree -instcombine -barrier -float2int -domtree -loops -loop-simplify -lcssa -loop-rotate -branch-prob -block-freq -scalar-evolution -loop-accesses -loop-vectorize -instcombine -scalar-evolution -slp-vectorizer -simplifycfg -domtree -instcombine -loops -loop-simplify -lcssa -scalar-evolution -loop-unroll -instcombine -loop-simplify -lcssa -licm -scalar-evolution -alignment-from-assumptions -strip-dead-prototypes -elim-avail-extern -globaldce -constmerge -verify
我有一个 LLVM IR 源文件，当我优化它时它会改变行为。我想知道是哪个 LLVM pass 造成的。
这是预期的行为，标准输入中的数字因式分解：
$ wget https://gist.githubusercontent.com/Wilfred/dde83b701d9bb8d7207a/raw/3eea89526ded7efa995f5bda89012b526dd49691/with_zeroing.ll
$ echo 1337 | lli with_zeroing.ll
1337: 7 191
在运行到opt之后，只是呼应原来的数字：
$ opt -S -O2 with_zeroing.ll -o with_zeroing_o2.ll
$ echo 1337 | lli with_zeroing_o2.ll
1337: 1337
如何使用 bugpoint 计算出哪个优化过程正在改变这种行为？
我试过 bugpoint with_zeroing.ll -llc-safe 但我想我需要一种将输入管道输入到生成的编译二进制文件中的方法。
LLVM 错误报告文档 has a great section on optimisation bugs。
首先，在您的代码中找出 opt 正在 运行 的通行证：
$ opt -O2 -debug-pass=Arguments with_zeroing.ll -disable-output
Pass Arguments: -tti -no-aa -tbaa -scoped-noalias -assumption-cache-tracker -targetlibinfo -basicaa -verify -simplifycfg -domtree -sroa -early-cse -lower-expect
Pass Arguments: -targetlibinfo -tti -no-aa -tbaa -scoped-noalias -assumption-cache-tracker -basicaa -ipsccp -globalopt -deadargelim -domtree -instcombine -simplifycfg -basiccg -prune-eh -inline-cost -inline -functionattrs -domtree -sroa -early-cse -lazy-value-info -jump-threading -correlated-propagation -simplifycfg -domtree -instcombine -tailcallelim -simplifycfg -reassociate -domtree -loops -loop-simplify -lcssa -loop-rotate -licm -loop-unswitch -instcombine -scalar-evolution -loop-simplify -lcssa -indvars -loop-idiom -loop-deletion -loop-unroll -mldst-motion -domtree -memdep -gvn -memdep -memcpyopt -sccp -domtree -bdce -instcombine -lazy-value-info -jump-threading -correlated-propagation -domtree -memdep -dse -loops -loop-simplify -lcssa -licm -adce -simplifycfg -domtree -instcombine -barrier -float2int -domtree -loops -loop-simplify -lcssa -loop-rotate -branch-prob -block-freq -scalar-evolution -loop-accesses -loop-vectorize -instcombine -scalar-evolution -slp-vectorizer -simplifycfg -domtree -instcombine -loops -loop-simplify -lcssa -scalar-evolution -loop-unroll -instcombine -loop-simplify -lcssa -licm -scalar-evolution -alignment-from-assumptions -strip-dead-prototypes -elim-avail-extern -globaldce -constmerge -verify
接下来，使用 -input 调用错误点以指定程序的输入：
$ echo "1337" > input.txt
$ bugpoint with_zeroing.ll -input input.txt -run-int \
-targetlibinfo -tti -no-aa -tbaa -scoped-noalias -assumption-cache-tracker -basicaa -ipsccp -globalopt -deadargelim -domtree -instcombine -simplifycfg -basiccg -prune-eh -inline-cost -inline -functionattrs -domtree -sroa -early-cse -lazy-value-info -jump-threading -correlated-propagation -simplifycfg -domtree -instcombine -tailcallelim -simplifycfg -reassociate -domtree -loops -loop-simplify -lcssa -loop-rotate -licm -loop-unswitch -instcombine -scalar-evolution -loop-simplify -lcssa -indvars -loop-idiom -loop-deletion -loop-unroll -mldst-motion -domtree -memdep -gvn -memdep -memcpyopt -sccp -domtree -bdce -instcombine -lazy-value-info -jump-threading -correlated-propagation -domtree -memdep -dse -loops -loop-simplify -lcssa -licm -adce -simplifycfg -domtree -instcombine -barrier -float2int -domtree -loops -loop-simplify -lcssa -loop-rotate -branch-prob -block-freq -scalar-evolution -loop-accesses -loop-vectorize -instcombine -scalar-evolution -slp-vectorizer -simplifycfg -domtree -instcombine -loops -loop-simplify -lcssa -scalar-evolution -loop-unroll -instcombine -loop-simplify -lcssa -licm -scalar-evolution -alignment-from-assumptions -strip-dead-prototypes -elim-avail-extern -globaldce -constmerge -verify