Make getDISubprogram(const Function *F) available in LLVM

[timurrrr]

Summary

This will be used in D5772

[timurrrr]

Minor fixes

[timurrrr]

Minor performance optimization

[majnemer]

LGTM

[timurrrr]

r220536, thanks!

[dnovillo]

Thanks for the cleanup!

lib/IR/DebugInfo.cpp

915

Could you leave the original documentation in?

[timurrrr]

lib/IR/DebugInfo.cpp

915

Can you please elaborate the request?
The "interface" part of the documentation has moved in include/llvm/IR/DebugInfo.h, the "implementation" part of the documentation is now located here.

include/llvm/IR/DebugInfo.h

public:
   unsigned getLineNumber() const { return getHeaderFieldAs<unsigned>(1); }
   StringRef getName() const { return getHeaderField(2); }
   bool Verify() const;
 };
 
 /// \brief Find subprogram that is enclosing this scope.
 DISubprogram getDISubprogram(const MDNode *Scope);
 
+/// \brief Find debug info for a given function.
+/// \returns a valid DISubprogram, if found. Otherwise, it returns an empty
+/// DISubprogram.
+DISubprogram getDISubprogram(const Function *F);
+
 /// \brief Find underlying composite type.
 DICompositeType getDICompositeType(DIType T);
 
 /// \brief Create a new inlined variable based on current variable.
 ///
 /// @param DV            Current Variable.
 /// @param InlinedScope  Location at current variable is inlined.
 DIVariable createInlinedVariable(MDNode *DV, MDNode *InlinedScope,

lib/IR/DebugInfo.cpp

if (D.isLexicalBlockFile())
     return getDISubprogram(DILexicalBlockFile(Scope).getContext());
 
   if (D.isLexicalBlock())
     return getDISubprogram(DILexicalBlock(Scope).getContext());
 
   return DISubprogram();
 }
 
+DISubprogram llvm::getDISubprogram(const Function *F) {
+  // We look for the first instr that has a debug annotation leading back to F.
+  const LLVMContext &Ctx = F->getParent()->getContext();
+  for (auto &BB : *F) {
+    for (auto &Inst : BB.getInstList()) {
+      DebugLoc DLoc = Inst.getDebugLoc();
+      if (DLoc.isUnknown())
+        continue;
+      const MDNode *Scope = DLoc.getScopeNode(Ctx);
+      DISubprogram Subprogram = getDISubprogram(Scope);
+      if (Subprogram.describes(F))
+       return Subprogram;
+    }
+  }
+
+  return DISubprogram();
+}
+
 DICompositeType llvm::getDICompositeType(DIType T) {
   if (T.isCompositeType())
     return DICompositeType(T);
 
   if (T.isDerivedType()) {
     // This function is currently used by dragonegg and dragonegg does
     // not generate identifier for types, so using an empty map to resolve
     // DerivedFrom should be fine.

lib/Transforms/Scalar/SampleProfile.cpp

if (!AllWeightsZero) {
       TI->setMetadata(llvm::LLVMContext::MD_prof,
                       MDB.createBranchWeights(Weights));
     } else {
       DEBUG(dbgs() << "SKIPPED. All branch weights are zero.\n");
     }
   }
 }
 
-/// \brief Locate the DISubprogram for F.
-///
-/// We look for the first instruction that has a debug annotation
-/// leading back to \p F.
-///
-/// \returns a valid DISubprogram, if found. Otherwise, it returns an empty
-/// DISubprogram.
-static const DISubprogram getDISubprogram(Function &F, const LLVMContext &Ctx) {
-  for (auto &BI : F) {
-    BasicBlock *BB = &BI;
-    for (auto &Inst : BB->getInstList()) {
-      DebugLoc DLoc = Inst.getDebugLoc();
-      if (DLoc.isUnknown())
-        continue;
-      const MDNode *Scope = DLoc.getScopeNode(Ctx);
-      DISubprogram Subprogram = getDISubprogram(Scope);
-      return Subprogram.describes(&F) ? Subprogram : DISubprogram();
-    }
-  }
-
-  return DISubprogram();
-}
-
 /// \brief Get the line number for the function header.
 ///
 /// This looks up function \p F in the current compilation unit and
 /// retrieves the line number where the function is defined. This is
 /// line 0 for all the samples read from the profile file. Every line
 /// number is relative to this line.
 ///
 /// \param F  Function object to query.
 ///
 /// \returns the line number where \p F is defined. If it returns 0,
 ///          it means that there is no debug information available for \p F.
 unsigned SampleProfileLoader::getFunctionLoc(Function &F) {
-  const DISubprogram &S = getDISubprogram(F, *Ctx);
+  DISubprogram S = getDISubprogram(&F);
   if (S.isSubprogram())
     return S.getLineNumber();
 
   // If could not find the start of \p F, emit a diagnostic to inform the user
   // about the missed opportunity.
   F.getContext().diagnose(DiagnosticInfoSampleProfile(
       "No debug information found in function " + F.getName() +
           ": Function profile not used",