Shishir V Jessu via llvm-dev
2019-Sep-30 19:41 UTC
[llvm-dev] Debugging LowerTypeTests in LLVM Using GDB
Hi, I am looking into Control-Flow Integrity for indirect function calls, implemented with jump tables. I want to step through the code that produces these jump tables in GDB. I have built clang and opt from source with debugging symbols. I believe this code lives in llvm/lib/Transforms/LowerTypeTests.cpp, but when I try to debug *opt* by running the command "run -lowertypetests cfi-icall.bc > /dev/null", I am never able to reach this file. Also, I have tried to debug the command "clang -flto -fsanitize=cfi-icall indirect.c -o indirect" (where indirect.c is a C file containing an indirect call), and am able to see the CFI jump tables in the resulting assembly, but I cannot reach the code that produces these jump tables in GDB. Am I targeting the wrong code for these changes, or is there something more I need in order to run through this code in GDB? Thanks for your help! Shishir Jessu -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20190930/2a8594de/attachment.html>
`clang` is the driver not the compiler. Run this to get the compiler invocation: (“path/to/clang” “-cc1” ….), then debug that instead. "clang -flto -fsanitize=cfi-icall indirect.c -o indirect -###" -Yuanfang From: llvm-dev <llvm-dev-bounces at lists.llvm.org> On Behalf Of Shishir V Jessu via llvm-dev Sent: Monday, September 30, 2019 12:42 PM To: llvm-dev at lists.llvm.org Subject: [llvm-dev] Debugging LowerTypeTests in LLVM Using GDB Hi, I am looking into Control-Flow Integrity for indirect function calls, implemented with jump tables. I want to step through the code that produces these jump tables in GDB. I have built clang and opt from source with debugging symbols. I believe this code lives in llvm/lib/Transforms/LowerTypeTests.cpp, but when I try to debug opt by running the command "run -lowertypetests cfi-icall.bc > /dev/null", I am never able to reach this file. Also, I have tried to debug the command "clang -flto -fsanitize=cfi-icall indirect.c -o indirect" (where indirect.c is a C file containing an indirect call), and am able to see the CFI jump tables in the resulting assembly, but I cannot reach the code that produces these jump tables in GDB. Am I targeting the wrong code for these changes, or is there something more I need in order to run through this code in GDB? Thanks for your help! Shishir Jessu [https://my-email-signature.link/signature.gif?u=452460&e=69832799&v=6efa26dd8b7b5e591d1b31d3c4a3519873f620bdba0e97b50ce1fae745e580e7] -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20190930/6f7518b1/attachment.html>
Shishir V Jessu via llvm-dev
2019-Sep-30 23:21 UTC
[llvm-dev] Debugging LowerTypeTests in LLVM Using GDB
Hi Yuanfang, Do you have any guidance about how to proceed from here? The following is the output from the command you've given: "Target: x86_64-unknown-linux-gnuThread model: posixInstalledDir: /home/shishir_jessu/clang/build/bin/. "/home/shishir_jessu/clang/build/bin/clang-10" "-cc1" "-triple" "x86_64-unknown-linux-gnu" "-emit-llvm-bc" "-flto" "-flto-unit" "-disable-free" "-main-file-name" "indirect.c" "-mrelocation-model" "static" "-mthread-model" "posix" "-mframe-pointer=all" "-fmath-errno" "-masm-verbose" "-mconstructor-aliases" "-munwind-tables" "-fuse-init-array" "-target-cpu" "x86-64" "-dwarf-column-info" "-debugger-tuning=gdb" "-resource-dir" "/home/shishir_jessu/clang/build/lib/clang/10.0.0" "-internal-isystem" "/usr/local/include" "-internal-isystem" "/home/shishir_jessu/clang/build/lib/clang/10.0.0/include" "-internal-externc-isystem" "/usr/include/x86_64-linux-gnu" "-internal-externc-isystem" "/include" "-internal-externc-isystem" "/usr/include" "-fdebug-compilation-dir" "/home/shishir_jessu/clang/build/bin" "-ferror-limit" "19" "-fmessage-length" "0" "-fsanitize=cfi-icall" "-fsanitize-trap=cfi-icall" "-fsanitize-blacklist=/home/shishir_jessu/clang/build/lib/clang/10.0.0/share/cfi_blacklist.txt" "-fsanitize-cfi-canonical-jump-tables" "-fobjc-runtime=gcc" "-fdiagnostics-show-option" "-fcolor-diagnostics" "-fsplit-lto-unit" "-faddrsig" "-o" "/tmp/indirect-1aceda.o" "-x" "c" "indirect.c" "/usr/bin/ld" "-z" "relro" "--hash-style=gnu" "--eh-frame-hdr" "-m" "elf_x86_64" "-dynamic-linker" "/lib64/ld-linux-x86-64.so.2" "-o" "indirect" "/usr/lib/gcc/x86_64-linux-gnu/7.4.0/../../../x86_64-linux-gnu/crt1.o" "/usr/lib/gcc/x86_64-linux-gnu/7.4.0/../../../x86_64-linux-gnu/crti.o" "/usr/lib/gcc/x86_64-linux-gnu/7.4.0/crtbegin.o" "-L/usr/lib/gcc/x86_64-linux-gnu/7.4.0" "-L/usr/lib/gcc/x86_64-linux-gnu/7.4.0/../../../x86_64-linux-gnu" "-L/lib/x86_64-linux-gnu" "-L/lib/../lib64" "-L/usr/lib/x86_64-linux-gnu" "-L/usr/lib/gcc/x86_64-linux-gnu/7.4.0/../../.." "-L/home/shishir_jessu/clang/build/bin/../lib" "-L/lib" "-L/usr/lib" "-plugin" "/home/shishir_jessu/clang/build/bin/../lib/LLVMgold.so" "-plugin-opt=mcpu=x86-64" "/tmp/indirect-1aceda.o" "-lgcc" "--as-needed" "-lgcc_s" "--no-as-needed" "-lc" "-lgcc" "--as-needed" "-lgcc_s" "--no-as-needed" "/usr/lib/gcc/x86_64-linux-gnu/7.4.0/crtend.o" "/usr/lib/gcc/x86_64-linux-gnu/7.4.0/../../../x86_64-linux-gnu/crtn.o" Of the flags given, I only need one of them. So I run clang -cc1 -fsanitizecfi-icall indirect.c, but am still not able to hit the code I'm looking for. Is there anything else I should be doing? Thank you! Shishir Jessu On Mon, Sep 30, 2019 at 2:55 PM <Yuanfang.Chen at sony.com> wrote:> `clang` is the driver not the compiler. > > > > Run this to get the compiler invocation: (“path/to/clang” “-cc1” ….), then > debug that instead. > > "clang -flto -fsanitize=cfi-icall indirect.c -o indirect -###" > > > > -Yuanfang > > > > *From:* llvm-dev <llvm-dev-bounces at lists.llvm.org> *On Behalf Of *Shishir > V Jessu via llvm-dev > *Sent:* Monday, September 30, 2019 12:42 PM > *To:* llvm-dev at lists.llvm.org > *Subject:* [llvm-dev] Debugging LowerTypeTests in LLVM Using GDB > > > > Hi, > > I am looking into Control-Flow Integrity for indirect function calls, > implemented with jump tables. I want to step through the code that produces > these jump tables in GDB. I have built clang and opt from source with > debugging symbols. I believe this code lives in > llvm/lib/Transforms/LowerTypeTests.cpp, but when I try to debug *opt* by > running the command "run -lowertypetests cfi-icall.bc > /dev/null", I am > never able to reach this file. > > Also, I have tried to debug the command "clang -flto -fsanitize=cfi-icall > indirect.c -o indirect" (where indirect.c is a C file containing an > indirect call), and am able to see the CFI jump tables in the resulting > assembly, but I cannot reach the code that produces these jump tables in > GDB. Am I targeting the wrong code for these changes, or is there something > more I need in order to run through this code in GDB? Thanks for your help! > > Shishir Jessu > >-------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20190930/40284153/attachment.html>
PenYiWang via llvm-dev
2019-Oct-01 00:17 UTC
[llvm-dev] Fwd: Debugging LowerTypeTests in LLVM Using GDB
---------- Forwarded message --------- 寄件者： PenYiWang <s89162504 at gmail.com> Date: 2019年10月1日 週二 08:14 Subject: Re: [llvm-dev] Debugging LowerTypeTests in LLVM Using GDB To: Shishir V Jessu <shishir.jessu at utexas.edu> LLVM CFI is at LTO time you should use -v option to see how clang invoke /usr/bin/ld with llvm gold plugin to run LTO pass or use "opt -lowertypetests ...." Shishir V Jessu via llvm-dev <llvm-dev at lists.llvm.org> 於 2019年10月1日 週二 07:22 寫道：> Hi Yuanfang, > > Do you have any guidance about how to proceed from here? The following is > the output from the command you've given: > > "Target: x86_64-unknown-linux-gnuThread model: posixInstalledDir: /home/shishir_jessu/clang/build/bin/. "/home/shishir_jessu/clang/build/bin/clang-10" "-cc1" "-triple" "x86_64-unknown-linux-gnu" "-emit-llvm-bc" "-flto" "-flto-unit" "-disable-free" "-main-file-name" "indirect.c" "-mrelocation-model" "static" "-mthread-model" "posix" "-mframe-pointer=all" "-fmath-errno" "-masm-verbose" "-mconstructor-aliases" "-munwind-tables" "-fuse-init-array" "-target-cpu" "x86-64" "-dwarf-column-info" "-debugger-tuning=gdb" "-resource-dir" "/home/shishir_jessu/clang/build/lib/clang/10.0.0" "-internal-isystem" "/usr/local/include" "-internal-isystem" "/home/shishir_jessu/clang/build/lib/clang/10.0.0/include" "-internal-externc-isystem" "/usr/include/x86_64-linux-gnu" "-internal-externc-isystem" "/include" "-internal-externc-isystem" "/usr/include" "-fdebug-compilation-dir" "/home/shishir_jessu/clang/build/bin" "-ferror-limit" "19" "-fmessage-length" "0" "-fsanitize=cfi-icall" "-fsanitize-trap=cfi-icall" "-fsanitize-blacklist=/home/shishir_jessu/clang/build/lib/clang/10.0.0/share/cfi_blacklist.txt" "-fsanitize-cfi-canonical-jump-tables" "-fobjc-runtime=gcc" "-fdiagnostics-show-option" "-fcolor-diagnostics" "-fsplit-lto-unit" "-faddrsig" "-o" "/tmp/indirect-1aceda.o" "-x" "c" "indirect.c" "/usr/bin/ld" "-z" "relro" "--hash-style=gnu" "--eh-frame-hdr" "-m" "elf_x86_64" "-dynamic-linker" "/lib64/ld-linux-x86-64.so.2" "-o" "indirect" "/usr/lib/gcc/x86_64-linux-gnu/7.4.0/../../../x86_64-linux-gnu/crt1.o" "/usr/lib/gcc/x86_64-linux-gnu/7.4.0/../../../x86_64-linux-gnu/crti.o" "/usr/lib/gcc/x86_64-linux-gnu/7.4.0/crtbegin.o" "-L/usr/lib/gcc/x86_64-linux-gnu/7.4.0" "-L/usr/lib/gcc/x86_64-linux-gnu/7.4.0/../../../x86_64-linux-gnu" "-L/lib/x86_64-linux-gnu" "-L/lib/../lib64" "-L/usr/lib/x86_64-linux-gnu" "-L/usr/lib/gcc/x86_64-linux-gnu/7.4.0/../../.." "-L/home/shishir_jessu/clang/build/bin/../lib" "-L/lib" "-L/usr/lib" "-plugin" "/home/shishir_jessu/clang/build/bin/../lib/LLVMgold.so" "-plugin-opt=mcpu=x86-64" "/tmp/indirect-1aceda.o" "-lgcc" "--as-needed" "-lgcc_s" "--no-as-needed" "-lc" "-lgcc" "--as-needed" "-lgcc_s" "--no-as-needed" "/usr/lib/gcc/x86_64-linux-gnu/7.4.0/crtend.o" "/usr/lib/gcc/x86_64-linux-gnu/7.4.0/../../../x86_64-linux-gnu/crtn.o" > > > Of the flags given, I only need one of them. So I run clang -cc1 - > fsanitize=cfi-icall indirect.c, but am still not able to hit the code > I'm looking for. Is there anything else I should be doing? Thank you! > > Shishir Jessu > > On Mon, Sep 30, 2019 at 2:55 PM <Yuanfang.Chen at sony.com> wrote: > >> `clang` is the driver not the compiler. >> >> >> >> Run this to get the compiler invocation: (“path/to/clang” “-cc1” ….), >> then debug that instead. >> >> "clang -flto -fsanitize=cfi-icall indirect.c -o indirect -###" >> >> >> >> -Yuanfang >> >> >> >> *From:* llvm-dev <llvm-dev-bounces at lists.llvm.org> *On Behalf Of *Shishir >> V Jessu via llvm-dev >> *Sent:* Monday, September 30, 2019 12:42 PM >> *To:* llvm-dev at lists.llvm.org >> *Subject:* [llvm-dev] Debugging LowerTypeTests in LLVM Using GDB >> >> >> >> Hi, >> >> I am looking into Control-Flow Integrity for indirect function calls, >> implemented with jump tables. I want to step through the code that produces >> these jump tables in GDB. I have built clang and opt from source with >> debugging symbols. I believe this code lives in >> llvm/lib/Transforms/LowerTypeTests.cpp, but when I try to debug *opt* by >> running the command "run -lowertypetests cfi-icall.bc > /dev/null", I am >> never able to reach this file. >> >> Also, I have tried to debug the command "clang -flto -fsanitize=cfi-icall >> indirect.c -o indirect" (where indirect.c is a C file containing an >> indirect call), and am able to see the CFI jump tables in the resulting >> assembly, but I cannot reach the code that produces these jump tables in >> GDB. Am I targeting the wrong code for these changes, or is there something >> more I need in order to run through this code in GDB? Thanks for your help! >> >> Shishir Jessu >> >> _______________________________________________ > LLVM Developers mailing list > llvm-dev at lists.llvm.org > https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev >-------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20191001/448eb145/attachment-0001.html>