[llvm-commits] [PATCH] Debug info utilities and printer pass

[Devang Patel]

Hi Torok,

On Dec 10, 2008, at 11:02 AM, Török Edwin wrote:

> Hi,
>
> [@John Criswell: this is a much improved version of SourceLocator I  
> sent
> you ages ago ;)]
>
> 01-bb.patch:
> BasicBlock::getUniquePredecessor -> similar to getSinglePredecessor()
> but works if there is a unique predecessor listed multiple times

This is OK.

> 02-intrin.patch:
> Introduce DbgFuncStart::getDisplayName() (which refers to unmangled C 
> ++
> name!), and DbgDeclareInst::getVariableName()
> Introduce include/llvm/Support/DebugInfo.h:

We already have include/llvm/Analysis/DebugInfo.h, so I suggest that  
you use another name for this new header.


+namespace llvm {
+  class DbgStopPointInst;
+  /// Finds the stoppoint coressponding to this instruction, that is  
the
+  /// stoppoint that dominates this instruction
+  static const DbgStopPointInst *findStopPoint(const Instruction *Inst)
+  {
+    if (isa<DbgStopPointInst>(Inst))
+      return cast<DbgStopPointInst>(Inst);

pl. use dyn_cast instead of isa + cast.

+
+    const BasicBlock *BB = Inst->getParent();
+    BasicBlock::const_iterator I = Inst, B;
+    do {
+      B = BB->begin();
+      // a BB consisting only of a terminator, can't have a stoppoint
+      if (I != B) {
+        do {
+          --I;
+          if (isa<DbgStopPointInst>(*I))
+            return cast<DbgStopPointInst>(&*I);
+        } while (I != B);
+      }
+      // this BB didn't have a stoppoint, if there is only one
+      // predecessor, look for a stoppoint there
+      // we could use getIDom(), but that would require dominator info
+      BB = I->getParent()->getUniquePredecessor();
+      if (BB)
+        I = BB->getTerminator();
+    } while (BB != 0);
+    return 0;
+  }
+
+  /// Finds the stoppoint corresponding to first real (non-debug  
intrinsic)
+  /// instruction in this Basic Block, and returns the stoppoint for  
it.
+  static const DbgStopPointInst *findBBStopPoint(const BasicBlock *BB)
+  {
+    for(BasicBlock::const_iterator I = BB->begin(), E = BB->end(); I ! 
= E; ++I) {
+      if (isa<DbgStopPointInst>(*I))
+        return cast<DbgStopPointInst>(&*I);
+    }
+    // fallback to looking for stoppoint of terminator inst
+    // useful if this BB contains no stoppoints, but unique  
predecessor does
+    return findStopPoint(BB->getTerminator());

This will iterate BB again again.


>
> findStopPoint: Instruction* -> associated StopPoint*
> findBBStopPoint: BasicBlock* -> associated StopPoint*
> findDbgDeclare: Value* -> associated DbgDeclareInst*
> This header may not be the best place, but if I place these in
> Support/<something>.cpp I get circular dependencies with VMCore
>
> 03-pass.patch:
> -print-dbg-info: An example pass that shows how to use the functions  
> in
> 02-intrin.patch, and how to handle debug info in general for the  
> purpose
> of mapping LLVM IR back to original source code.
> This pass can be very useful when developing other passes, because you
> can see which line a certain LLVM instruction corresponds to,
> and can see the unmangled name of functions.
>
> Do you see any problems with these patches, or can I go ahead and  
> commit
> them?
>
> Best regards,
> --Edwin
> <01-bb.patch><02-intrin.patch><03- 
> pass.patch>_______________________________________________
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-
Devang