feat(bb): stack traces for check_circuit

barretenberg/README.md

@@ -287,3 +287,68 @@ python3 -m http.server <port>
 ```
 
 and tunnel the port through ssh.
+
+### Debugging Verifification Failures
+
+The CicuitChecker::check_circuit function is used to get the gate index and block information about a failing circuit constraint.
+If you are in a scenario where you have a failing call to check_circuit and wish to get more information out of it than just the gate index, you can use this feature to get a stack trace, see example below.
+
+Usage instructions:
+- On ubuntu (or our mainframe accounts) use `sudo apt-get install libdw-dev` to support trace printing
+- Use `cmake --preset clang16-dbg-fast-circuit-check-traces` and `cmake --build --preset clang16-dbg-fast-circuit-check-traces` to enable the backward-cpp dependency through the CHECK_CIRCUIT_STACKTRACES CMake variable.
+- Run any case where you have a failing check_circuit call, you will now have a stack trace illuminating where this constraint was added in code.
+
+Caveats:
+- This works best for code that is not overly generic, i.e. where just the sequence of function calls carries a lot of information. It is possible to tag extra data along with the stack trace, this can be done as a followup, please leave feedback if desired.
+- There are certain functions like `assert_equals` that can cause gates that occur _before_ them to fail. If this would be useful to automatically report, please leave feedback.
+
+Example:
+```
+[ RUN      ] standard_circuit_constructor.test_check_circuit_broken
+Stack trace (most recent call last):
+#4    Source "_deps/gtest-src/googletest/src/gtest.cc", line 2845, in Run
+       2842:   if (!Test::HasFatalFailure() && !Test::IsSkipped()) {
+       2843:     // This doesn't throw as all user code that can throw are wrapped into
+       2844:     // exception handling code.
+      >2845:     test->Run();
+       2846:   }
+       2847:
+       2848:   if (test != nullptr) {
+#3    Source "_deps/gtest-src/googletest/src/gtest.cc", line 2696, in Run
+       2693:   // GTEST_SKIP().
+       2694:   if (!HasFatalFailure() && !IsSkipped()) {
+       2695:     impl->os_stack_trace_getter()->UponLeavingGTest();
+      >2696:     internal::HandleExceptionsInMethodIfSupported(this, &Test::TestBody,
+       2697:                                                   "the test body");
+       2698:   }
+#2  | Source "_deps/gtest-src/googletest/src/gtest.cc", line 2657, in HandleSehExceptionsInMethodIfSupported<testing::Test, void>
+    |  2655: #if GTEST_HAS_EXCEPTIONS
+    |  2656:     try {
+    | >2657:       return HandleSehExceptionsInMethodIfSupported(object, method, location);
+    |  2658:     } catch (const AssertionException&) {  // NOLINT
+    |  2659:       // This failure was reported already.
+      Source "_deps/gtest-src/googletest/src/gtest.cc", line 2621, in HandleExceptionsInMethodIfSupported<testing::Test, void>
+       2618:   }
+       2619: #else
+       2620:   (void)location;
+      >2621:   return (object->*method)();
+       2622: #endif  // GTEST_HAS_SEH
+       2623: }
+#1    Source "/mnt/user-data/adam/aztec-packages/barretenberg/cpp/src/barretenberg/circuit_checker/standard_circuit_builder.test.cpp", line 464, in TestBody
+        461:     uint32_t d_idx = circuit_constructor.add_variable(d);
+        462:     circuit_constructor.create_add_gate({ a_idx, b_idx, c_idx, fr::one(), fr::one(), fr::neg_one(), fr::zero() });
+        463:
+      > 464:     circuit_constructor.create_add_gate({ d_idx, c_idx, a_idx, fr::one(), fr::neg_one(), fr::neg_one(), fr::zero() });
+        465:
+        466:     bool result = CircuitChecker::check(circuit_constructor);
+        467:     EXPECT_EQ(result, false);
+#0    Source "/mnt/user-data/adam/aztec-packages/barretenberg/cpp/src/barretenberg/stdlib_circuit_builders/standard_circuit_builder.cpp", line 22, in create_add_gate
+         19: {
+         20:     this->assert_valid_variables({ in.a, in.b, in.c });
+         21:
+      >  22:     blocks.arithmetic.populate_wires(in.a, in.b, in.c);
+         23:     blocks.arithmetic.q_m().emplace_back(FF::zero());
+         24:     blocks.arithmetic.q_1().emplace_back(in.a_scaling);
+         25:     blocks.arithmetic.q_2().emplace_back(in.b_scaling);
+gate number4
+```

barretenberg/cpp/CMakeLists.txt

@@ -19,7 +19,7 @@ configure_file(
 # Add doxygen build command
 find_package(Doxygen)
 if (DOXYGEN_FOUND)
-add_custom_target(build_docs 
+add_custom_target(build_docs
 COMMAND ${DOXYGEN_EXECUTABLE} ${PROJECT_SOURCE_DIR}/docs/Doxyfile
 WORKING_DIRECTORY ${PROJECT_SOURCE_DIR}
 COMMENT "Generate documentation with Doxygen")
@@ -34,6 +34,8 @@ option(DISABLE_TBB "Intel Thread Building Blocks" ON)
 option(COVERAGE "Enable collecting coverage from tests" OFF)
 option(ENABLE_ASAN "Address sanitizer for debugging tricky memory corruption" OFF)
 option(ENABLE_HEAVY_TESTS "Enable heavy tests when collecting coverage" OFF)
+# Note: Must do 'sudo apt-get install libdw-dev' or equivalent
+option(CHECK_CIRCUIT_STACKTRACES "Enable (slow) stack traces for check circuit" OFF)
 
 if(CMAKE_SYSTEM_PROCESSOR MATCHES "aarch64" OR CMAKE_SYSTEM_PROCESSOR MATCHES "arm64")
     message(STATUS "Compiling for ARM.")
@@ -45,6 +47,10 @@ if(CMAKE_SYSTEM_PROCESSOR MATCHES "aarch64" OR CMAKE_SYSTEM_PROCESSOR MATCHES "a
     set(DISABLE_TBB 0)
 endif()
 
+if(CHECK_CIRCUIT_STACKTRACES)
+    add_compile_options(-DCHECK_CIRCUIT_STACKTRACES)
+endif()
+
 if(ENABLE_ASAN)
     add_compile_options(-fsanitize=address)
     add_link_options(-fsanitize=address)
@@ -136,6 +142,8 @@ include(cmake/gtest.cmake)
 include(cmake/benchmark.cmake)
 include(cmake/module.cmake)
 include(cmake/msgpack.cmake)
+include(cmake/backward-cpp.cmake)
+
 add_subdirectory(src)
 if (ENABLE_ASAN AND NOT(FUZZING))
     find_program(LLVM_SYMBOLIZER_PATH NAMES llvm-symbolizer-16)

barretenberg/cpp/CMakePresets.json

@@ -96,6 +96,16 @@
         "LDFLAGS": "-O2 -gdwarf-4"
       }
     },
+    {
+      "name": "clang16-dbg-fast-circuit-check-traces",
+      "displayName": "Optimized debug build with Clang-16 with stack traces for failing circuit checks",
+      "description": "Build with globally installed Clang-16 in optimized debug mode with stack traces for failing circuit checks",
+      "inherits": "clang16-dbg-fast",
+      "binaryDir": "build-debug-fast-circuit-check-traces",
+      "cacheVariables": {
+        "CHECK_CIRCUIT_STACKTRACES": "ON"
+      }
+    },
     {
       "name": "clang16-assert",
       "binaryDir": "build-assert",
@@ -405,6 +415,11 @@
       "inherits": "default",
       "configurePreset": "clang16-dbg-fast"
     },
+    {
+      "name": "clang16-dbg-fast-circuit-check-traces",
+      "inherits": "clang16-dbg-fast",
+      "configurePreset": "clang16-dbg-fast-circuit-check-traces"
+    },
     {
       "name": "clang16-assert",
       "inherits": "default",
@@ -480,12 +495,7 @@
       "configurePreset": "wasm",
       "inheritConfigureEnvironment": true,
       "jobs": 0,
-      "targets": [
-        "barretenberg.wasm",
-        "barretenberg",
-        "wasi",
-        "env"
-      ]
+      "targets": ["barretenberg.wasm", "barretenberg", "wasi", "env"]
     },
     {
       "name": "wasm-dbg",

barretenberg/cpp/cmake/backward-cpp.cmake

@@ -0,0 +1,11 @@
+if(CHECK_CIRCUIT_STACKTRACES)
+    include(FetchContent)
+
+    # Also requires one of: libbfd (gnu binutils), libdwarf, libdw (elfutils)
+    FetchContent_Declare(backward
+        GIT_REPOSITORY https://github.com/bombela/backward-cpp
+        GIT_TAG 51f0700452cf71c57d43c2d028277b24cde32502
+        SYSTEM          # optional, the Backward include directory will be treated as system directory
+    )
+    FetchContent_MakeAvailable(backward)
+endif()

barretenberg/cpp/cmake/module.cmake

@@ -56,6 +56,19 @@ function(barretenberg_module MODULE_NAME)
             ${TBB_IMPORTED_TARGETS}
         )
 
+        if(CHECK_CIRCUIT_STACKTRACES)
+            target_link_libraries(
+                ${MODULE_NAME}_objects
+                PUBLIC
+                Backward::Interface
+            )
+            target_link_options(
+                ${MODULE_NAME}
+                PRIVATE
+                -ldw -lelf
+            )
+        endif()
+
         # enable msgpack downloading via dependency (solves race condition)
         add_dependencies(${MODULE_NAME} msgpack-c)
         add_dependencies(${MODULE_NAME}_objects msgpack-c)
@@ -88,6 +101,19 @@ function(barretenberg_module MODULE_NAME)
         )
         list(APPEND exe_targets ${MODULE_NAME}_tests)
 
+        if(CHECK_CIRCUIT_STACKTRACES)
+            target_link_libraries(
+                ${MODULE_NAME}_test_objects
+                PUBLIC
+                Backward::Interface
+            )
+            target_link_options(
+                ${MODULE_NAME}_tests
+                PRIVATE
+                -ldw -lelf
+            )
+        endif()
+
         if(WASM)
             target_link_options(
                 ${MODULE_NAME}_tests
@@ -229,6 +255,18 @@ function(barretenberg_module MODULE_NAME)
                 benchmark::benchmark
                 ${TBB_IMPORTED_TARGETS}
             )
+            if(CHECK_CIRCUIT_STACKTRACES)
+                target_link_libraries(
+                    ${BENCHMARK_NAME}_bench_objects
+                    PUBLIC
+                    Backward::Interface
+                )
+                target_link_options(
+                    ${BENCHMARK_NAME}_bench
+                    PRIVATE
+                    -ldw -lelf
+                )
+            endif()
 
             # enable msgpack downloading via dependency (solves race condition)
             add_dependencies(${BENCHMARK_NAME}_bench_objects msgpack-c)

barretenberg/cpp/src/CMakeLists.txt

@@ -188,4 +188,16 @@ if(WASM)
         -nostartfiles -Wl,--no-entry,--export-dynamic
     )
 
+    if(CHECK_CIRCUIT_STACKTRACES)
+        target_link_libraries(
+            barretenberg.wasm
+            PUBLIC
+            Backward::Interface
+        )
+        target_link_options(
+            barretenberg.wasm
+            PRIVATE
+            -ldw -lelf
+        )
+    endif()
 endif()

barretenberg/cpp/src/barretenberg/bb/CMakeLists.txt

@@ -12,4 +12,16 @@ if (NOT(FUZZING))
         barretenberg
         env
     )
+    if(CHECK_CIRCUIT_STACKTRACES)
+        target_link_libraries(
+            bb
+            PUBLIC
+            Backward::Interface
+        )
+        target_link_options(
+            bb
+            PRIVATE
+            -ldw -lelf
+        )
+    endif()
 endif()

barretenberg/cpp/src/barretenberg/circuit_checker/standard_circuit_checker.hpp

@@ -25,6 +25,9 @@ class StandardCircuitChecker {
             FF gate_sum = block.q_m()[i] * left * right + block.q_1()[i] * left + block.q_2()[i] * right +
                           block.q_3()[i] * output + block.q_c()[i];
             if (!gate_sum.is_zero()) {
+#ifdef CHECK_CIRCUIT_STACKTRACES
+                block.stack_traces.print(i);
+#endif
                 info("gate number", i);
                 return false;
             }

barretenberg/cpp/src/barretenberg/circuit_checker/ultra_circuit_builder.test.cpp

@@ -323,7 +323,7 @@ TEST(ultra_circuit_constructor, sort_with_edges_gate)
     fr h = fr(8);
 
     {
-        UltraCircuitBuilder circuit_constructor = UltraCircuitBuilder();
+        UltraCircuitBuilder circuit_constructor;
         auto a_idx = circuit_constructor.add_variable(a);
         auto b_idx = circuit_constructor.add_variable(b);
         auto c_idx = circuit_constructor.add_variable(c);
@@ -339,7 +339,7 @@ TEST(ultra_circuit_constructor, sort_with_edges_gate)
     }
 
     {
-        UltraCircuitBuilder circuit_constructor = UltraCircuitBuilder();
+        UltraCircuitBuilder circuit_constructor;
         auto a_idx = circuit_constructor.add_variable(a);
         auto b_idx = circuit_constructor.add_variable(b);
         auto c_idx = circuit_constructor.add_variable(c);
@@ -355,7 +355,7 @@ TEST(ultra_circuit_constructor, sort_with_edges_gate)
         EXPECT_EQ(result, false);
     }
     {
-        UltraCircuitBuilder circuit_constructor = UltraCircuitBuilder();
+        UltraCircuitBuilder circuit_constructor;
         auto a_idx = circuit_constructor.add_variable(a);
         auto b_idx = circuit_constructor.add_variable(b);
         auto c_idx = circuit_constructor.add_variable(c);
@@ -371,7 +371,7 @@ TEST(ultra_circuit_constructor, sort_with_edges_gate)
         EXPECT_EQ(result, false);
     }
     {
-        UltraCircuitBuilder circuit_constructor = UltraCircuitBuilder();
+        UltraCircuitBuilder circuit_constructor;
         auto a_idx = circuit_constructor.add_variable(a);
         auto c_idx = circuit_constructor.add_variable(c);
         auto d_idx = circuit_constructor.add_variable(d);