llvm dev - Mar 2017 - Function to strip Module of all debug information

Hello,

I need to strip a Module of all debug information before sending it to
verifyModule (This is a Module meant for NVPTX code). I've been using
llvm::StripDebugInfo, but it doesn't strip some of the debug information.
Following is an output from Verifier::visitInstruction,

Cannot invoke an intrinsic other than donothing, patchpoint, statepoint,
coro_resume or coro_destroy
  store void (metadata, i64, metadata, metadata)* @llvm.dbg.value, void
(metadata, i64, metadata, metadata)** %polly_launch_0_param_7, align 8

Will the following change to lib/IR/DebugInfo.cpp help resolve the problem ?
@@ -312,7 +312,7 @@ bool llvm::StripDebugInfo(Module &M) {

     // We're stripping debug info, and without them, coverage information
     // doesn't quite make sense.
-    if (NMD->getName().startswith("llvm.dbg.") ||
+    if (NMD->getName().contains("llvm.dbg.") ||
         NMD->getName() == "llvm.gcov") {
       NMD->eraseFromParent();
       Changed = true

I'm not sure if NamedMDNodes are going to include instructions.

Although llvm::stripDebugInfo(Function &F) (called through StripDebugInfo
on Functions present in the Module) removes DbgInfoIntrinsic instructions,
it seems to miss this store instruction. Does this store to a
@llvm.dbg.value count as a DbgInfoIntrinsic instruction ?

Please suggest a function to strip even this instruction.

Also, what does storing something at a place pointed by a function pointer
mean in the context of a debug intrinsic ?

Thank You,
Sanjay
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> On Mar 19, 2017, at 8:41 AM, SANJAY SRIVALLABH SINGAPURAM via llvm-dev
<llvm-dev at lists.llvm.org> wrote:
> 
> Hello,
> 
> I need to strip a Module of all debug information before sending it to
verifyModule
It is not clear to me why?
> (This is a Module meant for NVPTX code). I've been using
llvm::StripDebugInfo, but it doesn't strip some of the debug information.
Following is an output from Verifier::visitInstruction,
> 
> Cannot invoke an intrinsic other than donothing, patchpoint, statepoint,
coro_resume or coro_destroy
>   store void (metadata, i64, metadata, metadata)* @llvm.dbg.value, void
(metadata, i64, metadata, metadata)** %polly_launch_0_param_7, align 8
This is not a debug info, this is a buggy IR!

> 
> Will the following change to lib/IR/DebugInfo.cpp help resolve the problem
?
It would resolve your problem, but this is not a correct solution I believe. So
we should rather understand where this store comes from and fix the code that
creates it.

— 
Mehdi


> @@ -312,7 +312,7 @@ bool llvm::StripDebugInfo(Module &M) {
>  
>      // We're stripping debug info, and without them, coverage
information
>      // doesn't quite make sense.
> -    if (NMD->getName().startswith("llvm.dbg.") ||
> +    if (NMD->getName().contains("llvm.dbg.") ||
>          NMD->getName() == "llvm.gcov") {
>        NMD->eraseFromParent();
>        Changed = true
> 
> I'm not sure if NamedMDNodes are going to include instructions.
> 
> Although llvm::stripDebugInfo(Function &F) (called through
StripDebugInfo on Functions present in the Module) removes DbgInfoIntrinsic
instructions, it seems to miss this store instruction. Does this store to a
@llvm.dbg.value count as a DbgInfoIntrinsic instruction ?
> 
> Please suggest a function to strip even this instruction.
> 
> Also, what does storing something at a place pointed by a function pointer
mean in the context of a debug intrinsic ?
> 
> Thank You,
> Sanjay
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
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