After to speaking to Devang and a number of other people at the developer's
conference, I was able to make some forward progress on getting debugging to
work. I'm now able to actually single-step through my program and set
breakpoints, and examine function parameters.
However, I'm also seeing a lot of new problems which weren't exposed
before.
After spending the better part of two days working on them, I'd like to
describe them here and get some advice on what I might be doing wrong.
#1) Class sizes coming out as zero.
In my frontend, I call DebugFactory::CreateCompositeTypeEx as follows:
DICompositeType di = dbgFactory_.CreateCompositeTypeEx(
type->typeClass() == Type::Class ? dwarf::DW_TAG_class_type :
dwarf::DW_TAG_structure_type,
dbgCompileUnit_,
type->typeDefn()->linkageName().c_str(),
genDIFile(type->typeDefn()),
getSourceLineNumber(type->typeDefn()->location()),
getSizeOfInBits(type->irType()),
getAlignOfInBits(type->irType()),
getInt64Val(0), 0,
DIType(),
dbgFactory_.GetOrCreateArray(members.data(), members.size()));
The 'getSizeOfInBits()' function and the others like it basically call
llvm::ConstantExpr::getSizeOf() and then multiple the result by 8. Looking
at the generated IR, I can see that the expressions look correct to me (I've
added some line breaks for clarity):
!15 = metadata !{i32 589826, metadata !2, metadata
!"tart.core.Object",
metadata !12, i32 9,
i64 mul (i64 ptrtoint (%tart.core.Object* getelementptr
(%tart.core.Object* null, i32 1) to i64), i64 8),
i6 4 mul (i64 ptrtoint (%tart.core.Object* getelementptr ({ i1,
%tart.core.Object }* null, i64 0, i32 1) to i64), i64 8),
i64 0, i32 0, null, metadata !16, i32 0, null} ; [ DW_TAG_class_type ]
However, when I print out the debugging information via dwarfdump, you can
see that the size of the object is zero:
<1>< 2233> DW_TAG_class_type
DW_AT_sibling <2295>
DW_AT_name tart.core.Object
* DW_AT_byte_size 0*
DW_AT_decl_file 65
DW_AT_decl_line 9
<2>< 2258> DW_TAG_member
DW_AT_name __tib
DW_AT_type <2228>
DW_AT_decl_file 65
DW_AT_decl_line 10
DW_AT_data_member_location DW_OP_plus_uconst 0
<2>< 2274> DW_TAG_member
DW_AT_name __gcstate
DW_AT_type <156>
DW_AT_decl_file 65
DW_AT_decl_line 11
DW_AT_data_member_location DW_OP_plus_uconst 0
In addition, it appears that all of the field offsets are zero as well - see
the DIEs immediately following the class definition.
#2) I can't seem to get llvm.dbg.declare() to work for local variables,
although it appears to work fine for function parameters. For example, look
at the following snippet of IR:
define {} @ReflectionTest.testModuleReflection(%ReflectionTest* %self) gc
"tart-gc" {
prologue:
%m = alloca %tart.reflect.Module*
call void @llvm.dbg.value(metadata !{%ReflectionTest* %self}, i64 0,
metadata !1176)
call void @llvm.dbg.declare(metadata !{%tart.reflect.Module** %m},
metadata !1177)
%0 = bitcast %tart.reflect.Module** %m to i8**, !dbg !1178
call void @llvm.gcroot(i8** %0, i8* null), !dbg !1178
In the debugger, I can examine the value of 'self', however when I
attempt
to print the value of 'm', gdb reports 'No symbol "m" in
current context.'
#3) When I use the -ka option with dwarfdump, I get tons of errors of the
following form:
<1>< 616> DW_TAG_class_type
DW_AT_sibling <791>
DW_AT_name tart.reflect.NameTable
DW_AT_byte_size 0
*** DWARF CHECK: DW_AT_decl_file: does not point to valid file info ***
DW_AT_decl_file 65
DW_AT_decl_line 6
However, I've double- and triple-checked my code. The code that generates a
DIFile looks like this:
DASSERT(srcPath.isAbsolute());
DASSERT(dbgCompileUnit_.Verify());
file = dbgFactory_.CreateFile(
srcPath.getLast(),
srcPath.getDirname(),
dbgCompileUnit_);
And you can see in the earlier example that I'm passing the generated DIFile
to CreateComplexTypeEx.
--
-- Talin
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On Nov 6, 2010, at 7:35 PM, Talin wrote:> After to speaking to Devang and a number of other people at the developer's conference, I was able to make some forward progress on getting debugging to work. I'm now able to actually single-step through my program and set breakpoints, and examine function parameters. > > However, I'm also seeing a lot of new problems which weren't exposed before. After spending the better part of two days working on them, I'd like to describe them here and get some advice on what I might be doing wrong. > > #1) Class sizes coming out as zero. > > In my frontend, I call DebugFactory::CreateCompositeTypeEx as follows: > > DICompositeType di = dbgFactory_.CreateCompositeTypeEx( > type->typeClass() == Type::Class ? dwarf::DW_TAG_class_type : dwarf::DW_TAG_structure_type, > dbgCompileUnit_, > type->typeDefn()->linkageName().c_str(), > genDIFile(type->typeDefn()), > getSourceLineNumber(type->typeDefn()->location()), > getSizeOfInBits(type->irType()), > getAlignOfInBits(type->irType()), > getInt64Val(0), 0, > DIType(), > dbgFactory_.GetOrCreateArray(members.data(), members.size())); > > The 'getSizeOfInBits()' function and the others like it basically call llvm::ConstantExpr::getSizeOf() and then multiple the result by 8. Looking at the generated IR, I can see that the expressions look correct to me (I've added some line breaks for clarity): > > !15 = metadata !{i32 589826, metadata !2, metadata !"tart.core.Object", metadata !12, i32 9, > i64 mul (i64 ptrtoint (%tart.core.Object* getelementptr (%tart.core.Object* null, i32 1) to i64), i64 8),This does not work. The DebugInfo accessors uses getSizeInBits() to get an integer for the size. You will have to modify it to get the value.> i6 4 mul (i64 ptrtoint (%tart.core.Object* getelementptr ({ i1, %tart.core.Object }* null, i64 0, i32 1) to i64), i64 8), > i64 0, i32 0, null, metadata !16, i32 0, null} ; [ DW_TAG_class_type ] > > However, when I print out the debugging information via dwarfdump, you can see that the size of the object is zero: > > <1>< 2233> DW_TAG_class_type > DW_AT_sibling <2295> > DW_AT_name tart.core.Object > DW_AT_byte_size 0 > DW_AT_decl_file 65 > DW_AT_decl_line 9 > <2>< 2258> DW_TAG_member > DW_AT_name __tib > DW_AT_type <2228> > DW_AT_decl_file 65 > DW_AT_decl_line 10 > DW_AT_data_member_location DW_OP_plus_uconst 0 > <2>< 2274> DW_TAG_member > DW_AT_name __gcstate > DW_AT_type <156> > DW_AT_decl_file 65 > DW_AT_decl_line 11 > DW_AT_data_member_location DW_OP_plus_uconst 0 > > In addition, it appears that all of the field offsets are zero as well - see the DIEs immediately following the class definition. > > #2) I can't seem to get llvm.dbg.declare() to work for local variables, although it appears to work fine for function parameters. For example, look at the following snippet of IR: > > define {} @ReflectionTest.testModuleReflection(%ReflectionTest* %self) gc "tart-gc" { > prologue: > %m = alloca %tart.reflect.Module* > call void @llvm.dbg.value(metadata !{%ReflectionTest* %self}, i64 0, metadata !1176) > call void @llvm.dbg.declare(metadata !{%tart.reflect.Module** %m}, metadata !1177) > %0 = bitcast %tart.reflect.Module** %m to i8**, !dbg !1178 > call void @llvm.gcroot(i8** %0, i8* null), !dbg !1178 > > In the debugger, I can examine the value of 'self', however when I attempt to print the value of 'm', gdb reports 'No symbol "m" in current context.'Are using -O0? You do not have line number info with dbg.declare intrinsic. FWIW, following works ... define void @foo() nounwind ssp { entry: %i = alloca i32, align 4 call void @llvm.dbg.declare(metadata !{i32* %i}, metadata !5), !dbg !8 store i32 2, i32* %i, align 4, !dbg !9 ret void, !dbg !10 } - Devang -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20101108/14357701/attachment.html>
On Mon, Nov 8, 2010 at 9:56 AM, Devang Patel <dpatel at apple.com> wrote:> > On Nov 6, 2010, at 7:35 PM, Talin wrote: > > After to speaking to Devang and a number of other people at the developer's > conference, I was able to make some forward progress on getting debugging to > work. I'm now able to actually single-step through my program and set > breakpoints, and examine function parameters. > > However, I'm also seeing a lot of new problems which weren't exposed > before. After spending the better part of two days working on them, I'd like > to describe them here and get some advice on what I might be doing wrong. > > #1) Class sizes coming out as zero. > > In my frontend, I call DebugFactory::CreateCompositeTypeEx as follows: > > DICompositeType di = dbgFactory_.CreateCompositeTypeEx( > type->typeClass() == Type::Class ? dwarf::DW_TAG_class_type : > dwarf::DW_TAG_structure_type, > dbgCompileUnit_, > type->typeDefn()->linkageName().c_str(), > genDIFile(type->typeDefn()), > getSourceLineNumber(type->typeDefn()->location()), > getSizeOfInBits(type->irType()), > getAlignOfInBits(type->irType()), > getInt64Val(0), 0, > DIType(), > dbgFactory_.GetOrCreateArray(members.data(), members.size())); > > The 'getSizeOfInBits()' function and the others like it basically call > llvm::ConstantExpr::getSizeOf() and then multiple the result by 8. Looking > at the generated IR, I can see that the expressions look correct to me (I've > added some line breaks for clarity): > > !15 = metadata !{i32 589826, metadata !2, metadata !"tart.core.Object", > metadata !12, i32 9, > i64 mul (i64 ptrtoint (%tart.core.Object* getelementptr > (%tart.core.Object* null, i32 1) to i64), i64 8), > > > > This does not work. The DebugInfo accessors uses getSizeInBits() to get an > integer for the size. You will have to modify it to get the value. >I'm not sure I understand what you are saying - isn't llvm::ConstantExpr::getSizeOf() and llvm::ConstantExpr::getAlignOf() the proper way to compute the size and alignment of a field? If those functions can't be used for debug info, then that's really inconvenient - I don't want to have to write my own calculations for it, since (a) I'm likely to get it wrong in some subtle way, and (b) I'd be duplicating code, since the same calculations need to be done in a lot of other places.> > i6 4 mul (i64 ptrtoint (%tart.core.Object* getelementptr ({ i1, > %tart.core.Object }* null, i64 0, i32 1) to i64), i64 8), > i64 0, i32 0, null, metadata !16, i32 0, null} ; [ DW_TAG_class_type > ] > > However, when I print out the debugging information via dwarfdump, you can > see that the size of the object is zero: > > <1>< 2233> DW_TAG_class_type > DW_AT_sibling <2295> > DW_AT_name tart.core.Object > * DW_AT_byte_size 0* > DW_AT_decl_file 65 > DW_AT_decl_line 9 > <2>< 2258> DW_TAG_member > DW_AT_name __tib > DW_AT_type <2228> > DW_AT_decl_file 65 > DW_AT_decl_line 10 > DW_AT_data_member_location DW_OP_plus_uconst 0 > <2>< 2274> DW_TAG_member > DW_AT_name __gcstate > DW_AT_type <156> > DW_AT_decl_file 65 > DW_AT_decl_line 11 > DW_AT_data_member_location DW_OP_plus_uconst 0 > > In addition, it appears that all of the field offsets are zero as well - > see the DIEs immediately following the class definition. > > #2) I can't seem to get llvm.dbg.declare() to work for local variables, > although it appears to work fine for function parameters. For example, look > at the following snippet of IR: > > define {} @ReflectionTest.testModuleReflection(%ReflectionTest* %self) gc > "tart-gc" { > prologue: > %m = alloca %tart.reflect.Module* > call void @llvm.dbg.value(metadata !{%ReflectionTest* %self}, i64 0, > metadata !1176) > call void @llvm.dbg.declare(metadata !{%tart.reflect.Module** %m}, > metadata !1177) > %0 = bitcast %tart.reflect.Module** %m to i8**, !dbg !1178 > call void @llvm.gcroot(i8** %0, i8* null), !dbg !1178 > > > In the debugger, I can examine the value of 'self', however when I attempt > to print the value of 'm', gdb reports 'No symbol "m" in current context.' > > > Are using -O0? You do not have line number info with dbg.declare intrinsic. > FWIW, following works ... > > define void @foo() nounwind ssp { > entry: > %i = alloca i32, align 4 > call void @llvm.dbg.declare(metadata !{i32* %i}, metadata !5), !dbg !8 > store i32 2, i32* %i, align 4, !dbg !9 > ret void, !dbg !10 > } > > - > Devang > > >-- -- Talin -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20101108/30755104/attachment.html>
On Mon, Nov 8, 2010 at 9:56 AM, Devang Patel <dpatel at apple.com> wrote:> > On Nov 6, 2010, at 7:35 PM, Talin wrote: > > After to speaking to Devang and a number of other people at the developer's > conference, I was able to make some forward progress on getting debugging to > work. I'm now able to actually single-step through my program and set > breakpoints, and examine function parameters. > > However, I'm also seeing a lot of new problems which weren't exposed > before. After spending the better part of two days working on them, I'd like > to describe them here and get some advice on what I might be doing wrong. > > #1) Class sizes coming out as zero. > > In my frontend, I call DebugFactory::CreateCompositeTypeEx as follows: > > DICompositeType di = dbgFactory_.CreateCompositeTypeEx( > type->typeClass() == Type::Class ? dwarf::DW_TAG_class_type : > dwarf::DW_TAG_structure_type, > dbgCompileUnit_, > type->typeDefn()->linkageName().c_str(), > genDIFile(type->typeDefn()), > getSourceLineNumber(type->typeDefn()->location()), > getSizeOfInBits(type->irType()), > getAlignOfInBits(type->irType()), > getInt64Val(0), 0, > DIType(), > dbgFactory_.GetOrCreateArray(members.data(), members.size())); > > The 'getSizeOfInBits()' function and the others like it basically call > llvm::ConstantExpr::getSizeOf() and then multiple the result by 8. Looking > at the generated IR, I can see that the expressions look correct to me (I've > added some line breaks for clarity): > > !15 = metadata !{i32 589826, metadata !2, metadata !"tart.core.Object", > metadata !12, i32 9, > i64 mul (i64 ptrtoint (%tart.core.Object* getelementptr > (%tart.core.Object* null, i32 1) to i64), i64 8), > > > > This does not work. The DebugInfo accessors uses getSizeInBits() to get an > integer for the size. You will have to modify it to get the value. > > i6 4 mul (i64 ptrtoint (%tart.core.Object* getelementptr ({ i1, > %tart.core.Object }* null, i64 0, i32 1) to i64), i64 8), > i64 0, i32 0, null, metadata !16, i32 0, null} ; [ DW_TAG_class_type > ] > > However, when I print out the debugging information via dwarfdump, you can > see that the size of the object is zero: > > <1>< 2233> DW_TAG_class_type > DW_AT_sibling <2295> > DW_AT_name tart.core.Object > * DW_AT_byte_size 0* > DW_AT_decl_file 65 > DW_AT_decl_line 9 > <2>< 2258> DW_TAG_member > DW_AT_name __tib > DW_AT_type <2228> > DW_AT_decl_file 65 > DW_AT_decl_line 10 > DW_AT_data_member_location DW_OP_plus_uconst 0 > <2>< 2274> DW_TAG_member > DW_AT_name __gcstate > DW_AT_type <156> > DW_AT_decl_file 65 > DW_AT_decl_line 11 > DW_AT_data_member_location DW_OP_plus_uconst 0 > > In addition, it appears that all of the field offsets are zero as well - > see the DIEs immediately following the class definition. > > #2) I can't seem to get llvm.dbg.declare() to work for local variables, > although it appears to work fine for function parameters. For example, look > at the following snippet of IR: > > define {} @ReflectionTest.testModuleReflection(%ReflectionTest* %self) gc > "tart-gc" { > prologue: > %m = alloca %tart.reflect.Module* > call void @llvm.dbg.value(metadata !{%ReflectionTest* %self}, i64 0, > metadata !1176) > call void @llvm.dbg.declare(metadata !{%tart.reflect.Module** %m}, > metadata !1177) > %0 = bitcast %tart.reflect.Module** %m to i8**, !dbg !1178 > call void @llvm.gcroot(i8** %0, i8* null), !dbg !1178 > > > In the debugger, I can examine the value of 'self', however when I attempt > to print the value of 'm', gdb reports 'No symbol "m" in current context.' > > > Are using -O0? You do not have line number info with dbg.declare intrinsic. > FWIW, following works ... > > define void @foo() nounwind ssp { > entry: > %i = alloca i32, align 4 > call void @llvm.dbg.declare(metadata !{i32* %i}, metadata !5), !dbg !8 > store i32 2, i32* %i, align 4, !dbg !9 > ret void, !dbg !10 > } >Hmm, well I modified the front-end to add the line number on the dbg.declare, and I still have the same problem - the debugger can see the function parameter 'self' but not the local variable 'm'. Here's what the IR looks like for me: define {} @ReflectionTest.testModuleReflection(%ReflectionTest* %self) gc "tart-gc" { prologue: %m = alloca %tart.reflect.Module*, !dbg !1410 call void @llvm.dbg.value(metadata !{%ReflectionTest* %self}, i64 0, metadata !1411) call void @llvm.dbg.declare(metadata !{%tart.reflect.Module** %m}, metadata !1412) %0 = bitcast %tart.reflect.Module** %m to i8**, !dbg !1413 call void @llvm.gcroot(i8** %0, i8* null), !dbg !1413 %gc_root = alloca %"tart.reflect.Type[]"*, !dbg !1414 %1 = bitcast %"tart.reflect.Type[]"** %gc_root to i8**, !dbg !1414 call void @llvm.gcroot(i8** %1, i8* null), !dbg !1414 %gc_root25 = alloca %"tart.reflect.Method[]"*, !dbg !1416 %2 = bitcast %"tart.reflect.Method[]"** %gc_root25 to i8**, !dbg !1416 call void @llvm.gcroot(i8** %2, i8* null), !dbg !1416 %gc_root29 = alloca %"tart.reflect.Method[]"*, !dbg !1418 %3 = bitcast %"tart.reflect.Method[]"** %gc_root29 to i8**, !dbg !1418 call void @llvm.gcroot(i8** %3, i8* null), !dbg !1418 %gc_root33 = alloca %"tart.reflect.Type[]"*, !dbg !1419 %4 = bitcast %"tart.reflect.Type[]"** %gc_root33 to i8**, !dbg !1419 call void @llvm.gcroot(i8** %4, i8* null), !dbg !1419 %gc_root36 = alloca %1*, !dbg !1420 %5 = bitcast %1** %gc_root36 to i8**, !dbg !1420 call void @llvm.gcroot(i8** %5, i8* null), !dbg !1420 %gc_root40 = alloca %1*, !dbg !1420 %6 = bitcast %1** %gc_root40 to i8**, !dbg !1420 call void @llvm.gcroot(i8** %6, i8* null), !dbg !1420 %gc_root43 = alloca %1*, !dbg !1422 %7 = bitcast %1** %gc_root43 to i8**, !dbg !1422 call void @llvm.gcroot(i8** %7, i8* null), !dbg !1422 %gc_root47 = alloca %1*, !dbg !1422 %8 = bitcast %1** %gc_root47 to i8**, !dbg !1422 call void @llvm.gcroot(i8** %8, i8* null), !dbg !1422 %gc_root50 = alloca %1*, !dbg !1424 %9 = bitcast %1** %gc_root50 to i8**, !dbg !1424 call void @llvm.gcroot(i8** %9, i8* null), !dbg !1424 %gc_root54 = alloca %1*, !dbg !1424 %10 = bitcast %1** %gc_root54 to i8**, !dbg !1424 call void @llvm.gcroot(i8** %10, i8* null), !dbg !1424 br label %entry, !dbg !725> - > Devang > > >-- -- Talin -------------- next part -------------- An HTML attachment was scrubbed... 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