Closed Remodor closed 1 month ago
vaivaswatha
commented
1 month ago I just tried the same steps, but with GDB, and it worked for me. Can you try GDB once? That way we'll be able to narrow down the problem a bit? I don't have LLDB at the moment but will try with it later on.
Remodor
commented
1 month ago Same problem:
gdb --args lli -jit-kind=mcjit hello.dbg.ll
GNU gdb (Ubuntu 15.0.50.20240403-0ubuntu1) 15.0.50.20240403-git
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Reading symbols from lli...
This GDB supports auto-downloading debuginfo from the following URLs:
<https://debuginfod.ubuntu.com>
Enable debuginfod for this session? (y or [n]) n
Debuginfod has been disabled.
To make this setting permanent, add 'set debuginfod enabled off' to .gdbinit.
(No debugging symbols found in lli)
(gdb) break hello.ll:25
No symbol table is loaded. Use the "file" command.
Make breakpoint pending on future shared library load? (y or [n]) n
(gdb) run
Starting program: /usr/lib/llvm-18/bin/lli -jit-kind=mcjit hello.dbg.ll
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
warning: could not find '.gnu_debugaltlink' file for /lib/x86_64-linux-gnu/libtinfo.so.6
No hello
[Inferior 1 (process 730) exited normally]Can you set the breakpoint at line 15 instead of line 25 and let me know what happens?
Remodor
commented
1 month ago That actually worked! Even with lldb. Adjusting the README.md would be a good help imo..
Thanks a lot. Is there a way to read memory/ content of variables?
vaivaswatha
commented
1 month ago That actually worked! Even with lldb. Adjusting the README.md would be a good help imo..
The README already mentions that the line number needs to be valid.
Thanks a lot. Is there a way to read memory/ content of variables?
Yes, but typically LLVM variables names are numbers (and GDB can't recognize them), unless the source specified proper names. To work around this you can specify the -instnamer flag to debugir to attach a valid name to variables. Then you can just print them in GDB.
vaivaswatha
commented
1 month ago
After building I followed the exact instructions in multiple ways and can't get the desired output.
Prerequisites
lldbversion18.1.8lliversionUbuntu LLVM version 18.1.8, Optimized build.Steps to Reproduce
hello.c
```c #includeusing this command:
producing
hello.ll:hello.ll
```llvm ; ModuleID = 'hello.c' source_filename = "hello.c" target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128" target triple = "x86_64-pc-linux-gnu" @.str = private unnamed_addr constant [6 x i8] c"hello\00", align 1 @.str.1 = private unnamed_addr constant [13 x i8] c"Hello World\0A\00", align 1 @.str.2 = private unnamed_addr constant [10 x i8] c"No hello\0A\00", align 1 ; Function Attrs: noinline nounwind optnone uwtable define dso_local i32 @main(i32 noundef %0, ptr noundef %1) #0 { %3 = alloca i32, align 4 %4 = alloca i32, align 4 %5 = alloca ptr, align 8 store i32 0, ptr %3, align 4 store i32 %0, ptr %4, align 4 store ptr %1, ptr %5, align 8 %6 = load ptr, ptr %5, align 8 %7 = getelementptr inbounds ptr, ptr %6, i64 0 %8 = load ptr, ptr %7, align 8 %9 = call i32 @strcmp(ptr noundef %8, ptr noundef @.str) #3 %10 = icmp ne i32 %9, 0 br i1 %10, label %13, label %11 11: ; preds = %2 %12 = call i32 (ptr, ...) @printf(ptr noundef @.str.1) br label %15 13: ; preds = %2 %14 = call i32 (ptr, ...) @printf(ptr noundef @.str.2) br label %15 15: ; preds = %13, %11 ret i32 0 } ; Function Attrs: nounwind willreturn memory(read) declare i32 @strcmp(ptr noundef, ptr noundef) #1 declare i32 @printf(ptr noundef, ...) #2 attributes #0 = { noinline nounwind optnone uwtable "frame-pointer"="all" "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" } attributes #1 = { nounwind willreturn memory(read) "frame-pointer"="all" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" } attributes #2 = { "frame-pointer"="all" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" } attributes #3 = { nounwind willreturn memory(read) } !llvm.module.flags = !{!0, !1, !2, !3, !4} !llvm.ident = !{!5} !0 = !{i32 1, !"wchar_size", i32 4} !1 = !{i32 8, !"PIC Level", i32 2} !2 = !{i32 7, !"PIE Level", i32 2} !3 = !{i32 7, !"uwtable", i32 2} !4 = !{i32 7, !"frame-pointer", i32 2} !5 = !{!"Ubuntu clang version 18.1.8 (++20240731024944+3b5b5c1ec4a3-1~exp1~20240731145000.144)"} ```using:
producing
hello.dbg.ll:hello.ll
```llvm ; ModuleID = 'hello.ll' source_filename = "hello.c" target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128" target triple = "x86_64-pc-linux-gnu" @.str = private unnamed_addr constant [6 x i8] c"hello\00", align 1 @.str.1 = private unnamed_addr constant [13 x i8] c"Hello World\0A\00", align 1 @.str.2 = private unnamed_addr constant [10 x i8] c"No hello\0A\00", align 1 ; Function Attrs: noinline nounwind optnone uwtable define dso_local i32 @main(i32 noundef %0, ptr noundef %1) #0 !dbg !9 { %3 = alloca i32, align 4, !dbg !14 %4 = alloca i32, align 4, !dbg !16 %5 = alloca ptr, align 8, !dbg !17 store i32 0, ptr %3, align 4, !dbg !18 store i32 %0, ptr %4, align 4, !dbg !19 store ptr %1, ptr %5, align 8, !dbg !20 %6 = load ptr, ptr %5, align 8, !dbg !21 %7 = getelementptr inbounds ptr, ptr %6, i64 0, !dbg !22 %8 = load ptr, ptr %7, align 8, !dbg !23 %9 = call i32 @strcmp(ptr noundef %8, ptr noundef @.str) #3, !dbg !24 %10 = icmp ne i32 %9, 0, !dbg !25 br i1 %10, label %13, label %11, !dbg !26 11: ; preds = %2 %12 = call i32 (ptr, ...) @printf(ptr noundef @.str.1), !dbg !27 br label %15, !dbg !29 13: ; preds = %2 %14 = call i32 (ptr, ...) @printf(ptr noundef @.str.2), !dbg !30 br label %15, !dbg !32 15: ; preds = %13, %11 ret i32 0, !dbg !33 } ; Function Attrs: nounwind willreturn memory(read) declare i32 @strcmp(ptr noundef, ptr noundef) #1 declare i32 @printf(ptr noundef, ...) #2 attributes #0 = { noinline nounwind optnone uwtable "frame-pointer"="all" "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" } attributes #1 = { nounwind willreturn memory(read) "frame-pointer"="all" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" } attributes #2 = { "frame-pointer"="all" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" } attributes #3 = { nounwind willreturn memory(read) } !llvm.module.flags = !{!0, !1, !2, !3, !4, !5} !llvm.ident = !{!6} !llvm.dbg.cu = !{!7} !0 = !{i32 1, !"wchar_size", i32 4} !1 = !{i32 8, !"PIC Level", i32 2} !2 = !{i32 7, !"PIE Level", i32 2} !3 = !{i32 7, !"uwtable", i32 2} !4 = !{i32 7, !"frame-pointer", i32 2} !5 = !{i32 2, !"Debug Info Version", i32 3} !6 = !{!"Ubuntu clang version 18.1.8 (++20240731024944+3b5b5c1ec4a3-1~exp1~20240731145000.144)"} !7 = distinct !DICompileUnit(language: DW_LANG_C99, file: !8, producer: "LLVM Version 18.1", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug) !8 = !DIFile(filename: "hello.ll", directory: "") !9 = distinct !DISubprogram(name: "main", linkageName: "main", scope: !8, file: !8, line: 10, type: !10, scopeLine: 12, spFlags: DISPFlagDefinition, unit: !7) !10 = !DISubroutineType(types: !11) !11 = !{!12, !12, !13} !12 = !DIBasicType(name: "i32", size: 32, encoding: DW_ATE_unsigned) !13 = !DIDerivedType(tag: DW_TAG_pointer_type, name: "ptr", baseType: null, size: 64, align: 64) !14 = !DILocation(line: 12, scope: !15) !15 = distinct !DILexicalBlock(scope: !9, file: !8, line: 12) !16 = !DILocation(line: 13, scope: !15) !17 = !DILocation(line: 14, scope: !15) !18 = !DILocation(line: 15, scope: !15) !19 = !DILocation(line: 16, scope: !15) !20 = !DILocation(line: 17, scope: !15) !21 = !DILocation(line: 18, scope: !15) !22 = !DILocation(line: 19, scope: !15) !23 = !DILocation(line: 20, scope: !15) !24 = !DILocation(line: 21, scope: !15) !25 = !DILocation(line: 22, scope: !15) !26 = !DILocation(line: 23, scope: !15) !27 = !DILocation(line: 26, scope: !28) !28 = distinct !DILexicalBlock(scope: !9, file: !8, line: 26) !29 = !DILocation(line: 27, scope: !28) !30 = !DILocation(line: 30, scope: !31) !31 = distinct !DILexicalBlock(scope: !9, file: !8, line: 30) !32 = !DILocation(line: 31, scope: !31) !33 = !DILocation(line: 34, scope: !34) !34 = distinct !DILexicalBlock(scope: !9, file: !8, line: 34) ```debugging: