Adding function debug information by georgemitenkov · Pull Request #628 · BlueBrain/nmodl

georgemitenkov · 2021-05-07T19:04:04Z

This PR introduces debug support to LLVM code generation pipeline. Currently, only basic support was added:

What is supported

Debug information about functions (name)
Debug information about module

What has been changed and added

A new class DebugBuilder was created. It is used as a wrapper around LLVM's DIBuilder and holds important information such as LLVMContext, debug file and compile unit. It also wraps DIBuilder's functionality into a more suitable API.
A temporary Location struct has been added. It encapsulates the location of the source AST construct and reflects ModToken on LLVM code generation level. It is only used if the location of the source NMODL function is known.
LLVM visitor know takes an extra add_debug_information flag and handles debug information creation. Fore readability, IRBuilder was renamed to ir_builder.
JIT runner is now able to listen for GDB, perf (build LLVM with -DLLVM_USE_PERF=ON) and VTune (build LLVM with -DLLVM_USE_INTEL_JITEVENTS=ON) events.

How to generate debug information

Debug information is attached to every function, procedure or artificially created kernel (and corresponding wrappers). For benchmarking, debug information is enabled by default. Debug information is enable by default, so to turn it off use --disable-debug-info flag. For example, the given NMODL

1   FUNCTION func(x) {
2     func = x
3   }
4
5   PROCEDURE proc() {}

is transformed (running ./bin/nmodl <filename>.mod llvm --ir ) into

define double @func(double %x1) !dbg !4 {
  ; ...
}

define i32 @proc() !dbg !6 {
  ; ...
}

!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!3}

!0 = distinct !DICompileUnit(language: DW_LANG_C, file: !1, producer: "NMODL-LLVM", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2)
!1 = !DIFile(filename: "foo", directory: ".")
!2 = !{}
!3 = !{i32 2, !"Debug Version", i32 3}
!4 = distinct !DISubprogram(name: "func", linkageName: "func", scope: null, file: !1, line: 1, type: !5, scopeLine: 1, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !2)
!5 = !DISubroutineType(types: !2)
!6 = distinct !DISubprogram(name: "proc", linkageName: "proc", scope: null, file: !1, line: 5, type: !5, scopeLine: 5, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !2)

fixes #592 #612

bbpbuildbot · 2021-05-07T19:04:06Z

Can one of the admins verify this patch?

* add new cmake option NMODL_ENABLE_JIT_EVENT_LISTENERS to enable perf & vtune * multiple calls to llvm_map_components_to_libnames doesnt work on linux and hence create list * fix BB5 CI with new llvm installation which has perf & vtune enabled * user perf & vtune listeners iff enabled via cmake option

pramodk

Quickly went through this and overall looks ok to me.

(See my changes in 651b257 and 3af2c1f to make it work on BB5 & linux)

pramodk · 2021-05-07T23:26:39Z

+    llvm_opt->add_flag("--add-debug-info",
+                       add_debug_information,
+                       "Add debug information ({})"_format(add_debug_information))->ignore_case();


Wondering if we should always add debug info (or have it ON)

We can, yes, then a flag --disable-debug-info can be used to turn it off instead. What do you think?

👍 : the reason I mentioned to make it ON is that during development we need this all the time. So we don't need to add one more flag to CLI. (at least for now)

Agree! Will change that!

pramodk · 2021-05-07T23:29:01Z

+/// we may want to handle this properly.
+struct Location {
+    /// Line in the file.
+    int line;
+
+    /// Column in the file.
+    int column;
+};


to understand - once we add proper Token to the CodegenFunction nodes then this won't be needed?

I am not sure here. So far I pass proper tokens from ProcedureBlock and FunctionBlock, so that the lines are known. But if the node is created artificially (e.g. in the kernel), there is no line/column information.

My idea for that class was to have it as a wrapper around location, so that Token is used on the lexer/parser level, and for code generation a Location wrapper is used (So we separate these two and can add some more functionality to location, such as loc.getNextLocation(), etc. Hence, knowing the location of the function start, we can know roughly locations of the inner AST nodes.) But that's not very defined to me yet - so I made this struct for now:)

Ok understood. Having bit separation with a wrapper not a bad idea. 👍

georgemitenkov · 2021-05-08T08:44:37Z

    // with listeners on (e.g. -DLLVM_USE_PERF=ON).
    if (benchmark_info) {
        gdb_event_listener = llvm::JITEventListener::createGDBRegistrationListener();
+#if defined(NMODL_HAVE_JIT_EVENT_LISTENERS)


It is actually safe to not use #if since if flag for listeners not set in LLVM build, these will be nullptr. But it is better not to rely on that, I agree!

But, note that if createPerfJITEventListener() and createIntelJITEventListener() are used but we are not linking to libraries or don't have them then we get undefined reference error. This is why added it.

I see, that's right!

@proc

Added debug support to LLVM code generation pipeline. Currently, only basic support was added: 1. Debug information about functions (name) 2. Debug information about module **What has been changed and added** 1. A new class `DebugBuilder` was created. It is used as a wrapper around LLVM's `DIBuilder` and holds important information such as `LLVMContext`, debug file and compile unit. It also wraps `DIBuilder`'s functionality into a more suitable API. 2. A temporary `Location` struct has been added. It encapsulates the location of the source AST construct and reflects `ModToken` on LLVM code generation level. It is only used if the location of the source NMODL function is known. 3. LLVM visitor know takes an extra `add_debug_information` flag and handles debug information creation. Fore readability, `IRBuilder` was renamed to `ir_builder`. 4. JIT runner is now able to listen for GDB, perf (build LLVM with `-DLLVM_USE_PERF=ON`) and VTune (build LLVM with `-DLLVM_USE_INTEL_JITEVENTS=ON`) events. 5. Necessary cmake changes were added to optionally support JIT event listeners (`-DNMODL_HAVE_JIT_EVENT_LISTENERS`). **How to generate debug information** Debug information is attached to every function, procedure or artificially created kernel (and corresponding wrappers). Debug information is enable by default, so to turn it off use ` --disable-debug-info` flag. For example, the given NMODL ```nmodl 1 FUNCTION func(x) { 2 func = x 3 } 4 5 PROCEDURE proc() {} ``` is transformed (running `./bin/nmodl <filename>.mod llvm --ir`) into ```llvm define double @func(double %x1) !dbg !4 { ; ... } define i32 @proc() !dbg !6 { ; ... } !llvm.dbg.cu = !{!0} !llvm.module.flags = !{!3} !0 = distinct !DICompileUnit(language: DW_LANG_C, file: !1, producer: "NMODL-LLVM", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2) !1 = !DIFile(filename: "foo", directory: ".") !2 = !{} !3 = !{i32 2, !"Debug Version", i32 3} !4 = distinct !DISubprogram(name: "func", linkageName: "func", scope: null, file: !1, line: 1, type: !5, scopeLine: 1, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !2) !5 = !DISubroutineType(types: !2) !6 = distinct !DISubprogram(name: "proc", linkageName: "proc", scope: null, file: !1, line: 5, type: !5, scopeLine: 5, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !2) ``` fixes #592 #612 Co-authored-by: Pramod Kumbhar <pramod.s.kumbhar@gmail.com>

@proc

Added debug support to LLVM code generation pipeline. Currently, only basic support was added: 1. Debug information about functions (name) 2. Debug information about module **What has been changed and added** 1. A new class `DebugBuilder` was created. It is used as a wrapper around LLVM's `DIBuilder` and holds important information such as `LLVMContext`, debug file and compile unit. It also wraps `DIBuilder`'s functionality into a more suitable API. 2. A temporary `Location` struct has been added. It encapsulates the location of the source AST construct and reflects `ModToken` on LLVM code generation level. It is only used if the location of the source NMODL function is known. 3. LLVM visitor know takes an extra `add_debug_information` flag and handles debug information creation. Fore readability, `IRBuilder` was renamed to `ir_builder`. 4. JIT runner is now able to listen for GDB, perf (build LLVM with `-DLLVM_USE_PERF=ON`) and VTune (build LLVM with `-DLLVM_USE_INTEL_JITEVENTS=ON`) events. 5. Necessary cmake changes were added to optionally support JIT event listeners (`-DNMODL_HAVE_JIT_EVENT_LISTENERS`). **How to generate debug information** Debug information is attached to every function, procedure or artificially created kernel (and corresponding wrappers). Debug information is enable by default, so to turn it off use ` --disable-debug-info` flag. For example, the given NMODL ```nmodl 1 FUNCTION func(x) { 2 func = x 3 } 4 5 PROCEDURE proc() {} ``` is transformed (running `./bin/nmodl <filename>.mod llvm --ir`) into ```llvm define double @func(double %x1) !dbg !4 { ; ... } define i32 @proc() !dbg !6 { ; ... } !llvm.dbg.cu = !{!0} !llvm.module.flags = !{!3} !0 = distinct !DICompileUnit(language: DW_LANG_C, file: !1, producer: "NMODL-LLVM", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2) !1 = !DIFile(filename: "foo", directory: ".") !2 = !{} !3 = !{i32 2, !"Debug Version", i32 3} !4 = distinct !DISubprogram(name: "func", linkageName: "func", scope: null, file: !1, line: 1, type: !5, scopeLine: 1, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !2) !5 = !DISubroutineType(types: !2) !6 = distinct !DISubprogram(name: "proc", linkageName: "proc", scope: null, file: !1, line: 5, type: !5, scopeLine: 5, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !2) ``` fixes #592 #612 Co-authored-by: Pramod Kumbhar <pramod.s.kumbhar@gmail.com>

@proc

Added debug support to LLVM code generation pipeline. Currently, only basic support was added: 1. Debug information about functions (name) 2. Debug information about module **What has been changed and added** 1. A new class `DebugBuilder` was created. It is used as a wrapper around LLVM's `DIBuilder` and holds important information such as `LLVMContext`, debug file and compile unit. It also wraps `DIBuilder`'s functionality into a more suitable API. 2. A temporary `Location` struct has been added. It encapsulates the location of the source AST construct and reflects `ModToken` on LLVM code generation level. It is only used if the location of the source NMODL function is known. 3. LLVM visitor know takes an extra `add_debug_information` flag and handles debug information creation. Fore readability, `IRBuilder` was renamed to `ir_builder`. 4. JIT runner is now able to listen for GDB, perf (build LLVM with `-DLLVM_USE_PERF=ON`) and VTune (build LLVM with `-DLLVM_USE_INTEL_JITEVENTS=ON`) events. 5. Necessary cmake changes were added to optionally support JIT event listeners (`-DNMODL_HAVE_JIT_EVENT_LISTENERS`). **How to generate debug information** Debug information is attached to every function, procedure or artificially created kernel (and corresponding wrappers). Debug information is enable by default, so to turn it off use ` --disable-debug-info` flag. For example, the given NMODL ```nmodl 1 FUNCTION func(x) { 2 func = x 3 } 4 5 PROCEDURE proc() {} ``` is transformed (running `./bin/nmodl <filename>.mod llvm --ir`) into ```llvm define double @func(double %x1) !dbg !4 { ; ... } define i32 @proc() !dbg !6 { ; ... } !llvm.dbg.cu = !{!0} !llvm.module.flags = !{!3} !0 = distinct !DICompileUnit(language: DW_LANG_C, file: !1, producer: "NMODL-LLVM", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2) !1 = !DIFile(filename: "foo", directory: ".") !2 = !{} !3 = !{i32 2, !"Debug Version", i32 3} !4 = distinct !DISubprogram(name: "func", linkageName: "func", scope: null, file: !1, line: 1, type: !5, scopeLine: 1, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !2) !5 = !DISubroutineType(types: !2) !6 = distinct !DISubprogram(name: "proc", linkageName: "proc", scope: null, file: !1, line: 5, type: !5, scopeLine: 5, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !2) ``` fixes #592 #612 Co-authored-by: Pramod Kumbhar <pramod.s.kumbhar@gmail.com>

@proc

Added debug support to LLVM code generation pipeline. Currently, only basic support was added: 1. Debug information about functions (name) 2. Debug information about module **What has been changed and added** 1. A new class `DebugBuilder` was created. It is used as a wrapper around LLVM's `DIBuilder` and holds important information such as `LLVMContext`, debug file and compile unit. It also wraps `DIBuilder`'s functionality into a more suitable API. 2. A temporary `Location` struct has been added. It encapsulates the location of the source AST construct and reflects `ModToken` on LLVM code generation level. It is only used if the location of the source NMODL function is known. 3. LLVM visitor know takes an extra `add_debug_information` flag and handles debug information creation. Fore readability, `IRBuilder` was renamed to `ir_builder`. 4. JIT runner is now able to listen for GDB, perf (build LLVM with `-DLLVM_USE_PERF=ON`) and VTune (build LLVM with `-DLLVM_USE_INTEL_JITEVENTS=ON`) events. 5. Necessary cmake changes were added to optionally support JIT event listeners (`-DNMODL_HAVE_JIT_EVENT_LISTENERS`). **How to generate debug information** Debug information is attached to every function, procedure or artificially created kernel (and corresponding wrappers). Debug information is enable by default, so to turn it off use ` --disable-debug-info` flag. For example, the given NMODL ```nmodl 1 FUNCTION func(x) { 2 func = x 3 } 4 5 PROCEDURE proc() {} ``` is transformed (running `./bin/nmodl <filename>.mod llvm --ir`) into ```llvm define double @func(double %x1) !dbg !4 { ; ... } define i32 @proc() !dbg !6 { ; ... } !llvm.dbg.cu = !{!0} !llvm.module.flags = !{!3} !0 = distinct !DICompileUnit(language: DW_LANG_C, file: !1, producer: "NMODL-LLVM", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2) !1 = !DIFile(filename: "foo", directory: ".") !2 = !{} !3 = !{i32 2, !"Debug Version", i32 3} !4 = distinct !DISubprogram(name: "func", linkageName: "func", scope: null, file: !1, line: 1, type: !5, scopeLine: 1, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !2) !5 = !DISubroutineType(types: !2) !6 = distinct !DISubprogram(name: "proc", linkageName: "proc", scope: null, file: !1, line: 5, type: !5, scopeLine: 5, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !2) ``` fixes #592 #612 Co-authored-by: Pramod Kumbhar <pramod.s.kumbhar@gmail.com>

@proc

Added debug support to LLVM code generation pipeline. Currently, only basic support was added: 1. Debug information about functions (name) 2. Debug information about module **What has been changed and added** 1. A new class `DebugBuilder` was created. It is used as a wrapper around LLVM's `DIBuilder` and holds important information such as `LLVMContext`, debug file and compile unit. It also wraps `DIBuilder`'s functionality into a more suitable API. 2. A temporary `Location` struct has been added. It encapsulates the location of the source AST construct and reflects `ModToken` on LLVM code generation level. It is only used if the location of the source NMODL function is known. 3. LLVM visitor know takes an extra `add_debug_information` flag and handles debug information creation. Fore readability, `IRBuilder` was renamed to `ir_builder`. 4. JIT runner is now able to listen for GDB, perf (build LLVM with `-DLLVM_USE_PERF=ON`) and VTune (build LLVM with `-DLLVM_USE_INTEL_JITEVENTS=ON`) events. 5. Necessary cmake changes were added to optionally support JIT event listeners (`-DNMODL_HAVE_JIT_EVENT_LISTENERS`). **How to generate debug information** Debug information is attached to every function, procedure or artificially created kernel (and corresponding wrappers). Debug information is enable by default, so to turn it off use ` --disable-debug-info` flag. For example, the given NMODL ```nmodl 1 FUNCTION func(x) { 2 func = x 3 } 4 5 PROCEDURE proc() {} ``` is transformed (running `./bin/nmodl <filename>.mod llvm --ir`) into ```llvm define double @func(double %x1) !dbg !4 { ; ... } define i32 @proc() !dbg !6 { ; ... } !llvm.dbg.cu = !{!0} !llvm.module.flags = !{!3} !0 = distinct !DICompileUnit(language: DW_LANG_C, file: !1, producer: "NMODL-LLVM", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2) !1 = !DIFile(filename: "foo", directory: ".") !2 = !{} !3 = !{i32 2, !"Debug Version", i32 3} !4 = distinct !DISubprogram(name: "func", linkageName: "func", scope: null, file: !1, line: 1, type: !5, scopeLine: 1, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !2) !5 = !DISubroutineType(types: !2) !6 = distinct !DISubprogram(name: "proc", linkageName: "proc", scope: null, file: !1, line: 5, type: !5, scopeLine: 5, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !2) ``` fixes #592 #612 Co-authored-by: Pramod Kumbhar <pramod.s.kumbhar@gmail.com>

@proc

Added debug support to LLVM code generation pipeline. Currently, only basic support was added: 1. Debug information about functions (name) 2. Debug information about module **What has been changed and added** 1. A new class `DebugBuilder` was created. It is used as a wrapper around LLVM's `DIBuilder` and holds important information such as `LLVMContext`, debug file and compile unit. It also wraps `DIBuilder`'s functionality into a more suitable API. 2. A temporary `Location` struct has been added. It encapsulates the location of the source AST construct and reflects `ModToken` on LLVM code generation level. It is only used if the location of the source NMODL function is known. 3. LLVM visitor know takes an extra `add_debug_information` flag and handles debug information creation. Fore readability, `IRBuilder` was renamed to `ir_builder`. 4. JIT runner is now able to listen for GDB, perf (build LLVM with `-DLLVM_USE_PERF=ON`) and VTune (build LLVM with `-DLLVM_USE_INTEL_JITEVENTS=ON`) events. 5. Necessary cmake changes were added to optionally support JIT event listeners (`-DNMODL_HAVE_JIT_EVENT_LISTENERS`). **How to generate debug information** Debug information is attached to every function, procedure or artificially created kernel (and corresponding wrappers). Debug information is enable by default, so to turn it off use ` --disable-debug-info` flag. For example, the given NMODL ```nmodl 1 FUNCTION func(x) { 2 func = x 3 } 4 5 PROCEDURE proc() {} ``` is transformed (running `./bin/nmodl <filename>.mod llvm --ir`) into ```llvm define double @func(double %x1) !dbg !4 { ; ... } define i32 @proc() !dbg !6 { ; ... } !llvm.dbg.cu = !{!0} !llvm.module.flags = !{!3} !0 = distinct !DICompileUnit(language: DW_LANG_C, file: !1, producer: "NMODL-LLVM", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2) !1 = !DIFile(filename: "foo", directory: ".") !2 = !{} !3 = !{i32 2, !"Debug Version", i32 3} !4 = distinct !DISubprogram(name: "func", linkageName: "func", scope: null, file: !1, line: 1, type: !5, scopeLine: 1, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !2) !5 = !DISubroutineType(types: !2) !6 = distinct !DISubprogram(name: "proc", linkageName: "proc", scope: null, file: !1, line: 5, type: !5, scopeLine: 5, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !2) ``` fixes #592 #612 Co-authored-by: Pramod Kumbhar <pramod.s.kumbhar@gmail.com>

georgemitenkov added the llvm label May 7, 2021

This was linked to issues May 7, 2021

Adding debug information for JIT compiled kernel? #592

Open

Adding debug symbols and metadata for profiling kernels #612

Closed

Base automatically changed from georgemitenkov/opt-levels to llvm May 7, 2021 22:13

georgemitenkov and others added 5 commits May 8, 2021 00:22

Debug information support for function symbols

b9bc14f

Refactoring and adding a main debug option

c8a19e9

Fixed cmake to optionally link event listeners

bb78276

Apply clang-format && cmake-format

3af2c1f

pramodk force-pushed the georgemitenkov/llvm-debug branch from bfc4299 to 651b257 Compare May 7, 2021 23:24

pramodk approved these changes May 7, 2021

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pramodk mentioned this pull request May 8, 2021

Rebase llvm on top of master branch #630

Closed

georgemitenkov commented May 8, 2021

View reviewed changes

Changed flag to disable debug information

0802934

pramodk approved these changes May 8, 2021

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georgemitenkov merged commit dc46b6b into llvm May 8, 2021

georgemitenkov deleted the georgemitenkov/llvm-debug branch May 8, 2021 09:44

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Adding function debug information#628

Adding function debug information#628
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