[llvm] r267370 - Verifier: Verify that each inlinable callsite of a debug-info-bearing function

Mon Apr 25 10:39:49 PDT 2016

> On Apr 25, 2016, at 10:33 AM, David Blaikie <dblaikie at gmail.com> wrote:
> 
> 
> 
> On Sun, Apr 24, 2016 at 3:23 PM, Adrian Prantl via llvm-commits <llvm-commits at lists.llvm.org <mailto:llvm-commits at lists.llvm.org>> wrote:
> Author: adrian
> Date: Sun Apr 24 17:23:13 2016
> New Revision: 267370
> 
> URL: http://llvm.org/viewvc/llvm-project?rev=267370&view=rev <http://llvm.org/viewvc/llvm-project?rev=267370&view=rev>
> Log:
> Verifier: Verify that each inlinable callsite of a debug-info-bearing function
> in a debug-info-bearing function has a debug location attached to it. Failure to
> do so causes an "!dbg attachment points at wrong subprogram for function"
> assertion failure when the inliner sets up inline scope info.
> 
> Great to have this check - though, as an FYI: This doesn't catch all the cases of the downstream assertion. The downstream assertion can be triggered through indirect scenarios:
> 
>   void f1();
>   inline __attribute__((alwaysinline)) void f2() { f1(); }
>   inline __attribute__((alwaysinline)) void f3() { f2(); } // make this nodebug or equivalent
>   void f4() { f3(); } // if f3 has no debugloc
> 
> Now you'll end up with the same problem if f2 is inlined into f3 (maybe even in the other order), producing instructions with debug locations - and then that's inlined into f4 at a callsite with no debugloc, leaving the instructions having debug locations that don't chain up to the f4 subprogram scope - but still chain up to the f2 subprogram scope.

Thanks for pointing this out! I hope that the (cheaper) check from this patch will be enough to diagnose the most obvious bugs in frontends though.

> 
> - Dave
> 
> 
> rdar://problem/25878916
> 
> This reaplies r267320 without changes after fixing an issue in the OpenMP IR
> generator in clang.
> 
> Added:
>     llvm/trunk/test/Verifier/callsite-dbgloc.ll
> Modified:
>     llvm/trunk/lib/IR/Verifier.cpp
>     llvm/trunk/test/DebugInfo/X86/arange-and-stub.ll
>     llvm/trunk/test/DebugInfo/X86/dbg-declare-arg.ll
> 
> Modified: llvm/trunk/lib/IR/Verifier.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/IR/Verifier.cpp?rev=267370&r1=267369&r2=267370&view=diff <http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/IR/Verifier.cpp?rev=267370&r1=267369&r2=267370&view=diff>
> ==============================================================================
> --- llvm/trunk/lib/IR/Verifier.cpp (original)
> +++ llvm/trunk/lib/IR/Verifier.cpp Sun Apr 24 17:23:13 2016
> @@ -2579,6 +2579,15 @@ void Verifier::verifyCallSite(CallSite C
>      }
>    }
> 
> +  // Verify that each inlinable callsite of a debug-info-bearing function in a
> +  // debug-info-bearing function has a debug location attached to it. Failure to
> +  // do so causes assertion failures when the inliner sets up inline scope info.
> +  if (I->getFunction()->getSubprogram() && CS.getCalledFunction() &&
> +      CS.getCalledFunction()->getSubprogram())
> +    Assert(I->getDebugLoc(), "inlinable function call in a function with debug "
> +                             "info must have a !dbg location",
> +           I);
> +
>    visitInstruction(*I);
>  }
> 
> 
> Modified: llvm/trunk/test/DebugInfo/X86/arange-and-stub.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/X86/arange-and-stub.ll?rev=267370&r1=267369&r2=267370&view=diff <http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/X86/arange-and-stub.ll?rev=267370&r1=267369&r2=267370&view=diff>
> ==============================================================================
> --- llvm/trunk/test/DebugInfo/X86/arange-and-stub.ll (original)
> +++ llvm/trunk/test/DebugInfo/X86/arange-and-stub.ll Sun Apr 24 17:23:13 2016
> @@ -18,7 +18,7 @@ define void @foo() !dbg !4 {
> 
>  define void @bar() personality i8* bitcast (void ()* @foo to i8*) !dbg !9 {
>    invoke void @foo()
> -          to label %invoke.cont unwind label %lpad
> +          to label %invoke.cont unwind label %lpad, !dbg !19
> 
>  invoke.cont:                                      ; preds = %0
>    ret void
> @@ -50,3 +50,4 @@ lpad:
>  !16 = !DISubrange(count: 1)
>  !17 = !{i32 2, !"Dwarf Version", i32 4}
>  !18 = !{i32 2, !"Debug Info Version", i32 3}
> +!19 = !DILocation(line: 0, scope: !9)
> 
> Modified: llvm/trunk/test/DebugInfo/X86/dbg-declare-arg.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/X86/dbg-declare-arg.ll?rev=267370&r1=267369&r2=267370&view=diff <http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/X86/dbg-declare-arg.ll?rev=267370&r1=267369&r2=267370&view=diff>
> ==============================================================================
> --- llvm/trunk/test/DebugInfo/X86/dbg-declare-arg.ll (original)
> +++ llvm/trunk/test/DebugInfo/X86/dbg-declare-arg.ll Sun Apr 24 17:23:13 2016
> @@ -54,7 +54,7 @@ entry:
>    store %class.A* %this, %class.A** %this.addr, align 8
>    call void @llvm.dbg.declare(metadata %class.A** %this.addr, metadata !43, metadata !DIExpression()), !dbg !44
>    %this1 = load %class.A*, %class.A** %this.addr
> -  call void @_ZN1AD2Ev(%class.A* %this1)
> +  call void @_ZN1AD2Ev(%class.A* %this1), !dbg !53
>    ret void, !dbg !45
>  }
> 
> @@ -124,3 +124,4 @@ entry:
>  !49 = distinct !DILexicalBlock(line: 2, column: 52, file: !51, scope: !25)
>  !51 = !DIFile(filename: "a.cc", directory: "/private/tmp")
>  !52 = !{i32 1, !"Debug Info Version", i32 3}
> +!53 = !DILocation(line: 0, scope: !22)
> 
> Added: llvm/trunk/test/Verifier/callsite-dbgloc.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Verifier/callsite-dbgloc.ll?rev=267370&view=auto <http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Verifier/callsite-dbgloc.ll?rev=267370&view=auto>
> ==============================================================================
> --- llvm/trunk/test/Verifier/callsite-dbgloc.ll (added)
> +++ llvm/trunk/test/Verifier/callsite-dbgloc.ll Sun Apr 24 17:23:13 2016
> @@ -0,0 +1,62 @@
> +; RUN: not llvm-as %s -o %t 2>&1 | FileCheck %s
> +; Created and then edited from
> 
> It'd be good to describe the required edits here? (so that if someone is trying to regenerate or otherwise understand this test they know what to look for)
> 

I did, next to the CHECK :-)

> +; Function Attrs: nounwind ssp uwtable
> +define void @g() #0 !dbg !11 {
> +entry:
> +; Manually removed !dbg.
> +; CHECK: inlinable function call in a function with debug info must have a !dbg location
> +  call void @h()
> +  ret void, !dbg !13
> +}
> +

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