Remove llvm::getDISubprogram in favor of Function::getSubprogram

llvm::getDISubprogram walks the instructions in a function, looking for one in the scope of the current function, so that it can find the !dbg entry for the subprogram itself.

Now that !dbg is attached to functions, this should not be necessary. This patch changes all uses to just query the subprogram directly on the function.

Ideally this should be NFC, but in reality its possible that a function:

has no !dbg (in which case there's likely a bug somewhere in an opt pass), or
that none of the instructions had a scope referencing the function, so we used to not find the !dbg on the function but now we will

Reviewed by Duncan Exon Smith.

Differential Revision: http://reviews.llvm.org/D18074

llvm-svn: 263184

include/llvm/IR/DebugInfo.h

@@ -39,11 +39,6 @@ typedef DenseMap<const MDString *, DIType *> DITypeIdentifierMap;
 /// \brief Find subprogram that is enclosing this scope.
 DISubprogram *getDISubprogram(const MDNode *Scope);
 
-/// \brief Find debug info for a given function.
-///
-/// \returns a valid subprogram, if found. Otherwise, return \c nullptr.
-DISubprogram *getDISubprogram(const Function *F);
-
 /// \brief Generate map by visiting all retained types.
 DITypeIdentifierMap generateDITypeIdentifierMap(const NamedMDNode *CU_Nodes);
 

lib/CodeGen/AsmPrinter/CodeViewDebug.cpp

@@ -412,7 +412,7 @@ void CodeViewDebug::emitDebugInfoForFunction(const Function *GV,
   assert(Fn);
 
   StringRef FuncName;
-  if (auto *SP = getDISubprogram(GV))
+  if (auto *SP = GV->getSubprogram())
     FuncName = SP->getDisplayName();
 
   // If our DISubprogram name is empty, use the mangled name.
@@ -752,7 +752,7 @@ void CodeViewDebug::endFunction(const MachineFunction *MF) {
   assert(FnDebugInfo.count(GV));
   assert(CurFn == &FnDebugInfo[GV]);
 
-  collectVariableInfo(getDISubprogram(GV));
+  collectVariableInfo(GV->getSubprogram());
 
   DebugHandlerBase::endFunction(MF);
 

lib/IR/DebugInfo.cpp

@@ -38,23 +38,6 @@ DISubprogram *llvm::getDISubprogram(const MDNode *Scope) {
   return nullptr;
 }
 
-DISubprogram *llvm::getDISubprogram(const Function *F) {
-  // We look for the first instr that has a debug annotation leading back to F.
-  for (auto &BB : *F) {
-    auto Inst = std::find_if(BB.begin(), BB.end(), [](const Instruction &Inst) {
-      return Inst.getDebugLoc();
-    });
-    if (Inst == BB.end())
-      continue;
-    DebugLoc DLoc = Inst->getDebugLoc();
-    const MDNode *Scope = DLoc.getInlinedAtScope();
-    auto *Subprogram = getDISubprogram(Scope);
-    return Subprogram->describes(F) ? Subprogram : nullptr;
-  }
-
-  return nullptr;
-}
-
 DITypeIdentifierMap
 llvm::generateDITypeIdentifierMap(const NamedMDNode *CU_Nodes) {
   DITypeIdentifierMap Map;

lib/Transforms/IPO/SampleProfile.cpp

@@ -1076,7 +1076,7 @@ void SampleProfileLoader::propagateWeights(Function &F) {
 /// \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) {
-  if (DISubprogram *S = getDISubprogram(&F))
+  if (DISubprogram *S = F.getSubprogram())
     return S->getLine();
 
   // If the start of \p F is missing, emit a diagnostic to inform the user
@@ -1182,7 +1182,7 @@ bool SampleProfileLoader::emitAnnotations(Function &F) {
     unsigned Coverage = CoverageTracker.computeCoverage(Used, Total);
     if (Coverage < SampleProfileRecordCoverage) {
       F.getContext().diagnose(DiagnosticInfoSampleProfile(
-          getDISubprogram(&F)->getFilename(), getFunctionLoc(F),
+          F.getSubprogram()->getFilename(), getFunctionLoc(F),
           Twine(Used) + " of " + Twine(Total) + " available profile records (" +
               Twine(Coverage) + "%) were applied",
           DS_Warning));
@@ -1195,7 +1195,7 @@ bool SampleProfileLoader::emitAnnotations(Function &F) {
     unsigned Coverage = CoverageTracker.computeCoverage(Used, Total);
     if (Coverage < SampleProfileSampleCoverage) {
       F.getContext().diagnose(DiagnosticInfoSampleProfile(
-          getDISubprogram(&F)->getFilename(), getFunctionLoc(F),
+          F.getSubprogram()->getFilename(), getFunctionLoc(F),
           Twine(Used) + " of " + Twine(Total) + " available profile samples (" +
               Twine(Coverage) + "%) were applied",
           DS_Warning));

lib/Transforms/Instrumentation/AddressSanitizer.cpp

@@ -1891,7 +1891,7 @@ void FunctionStackPoisoner::poisonStack() {
 
   int StackMallocIdx = -1;
   DebugLoc EntryDebugLocation;
-  if (auto SP = getDISubprogram(&F))
+  if (auto SP = F.getSubprogram())
     EntryDebugLocation = DebugLoc::get(SP->getScopeLine(), 0, SP);
 
   Instruction *InsBefore = AllocaVec[0];

lib/Transforms/Instrumentation/SanitizerCoverage.cpp

@@ -493,7 +493,7 @@ void SanitizerCoverageModule::InjectCoverageAtBlock(Function &F, BasicBlock &BB,
   bool IsEntryBB = &BB == &F.getEntryBlock();
   DebugLoc EntryLoc;
   if (IsEntryBB) {
-    if (auto SP = getDISubprogram(&F))
+    if (auto SP = F.getSubprogram())
       EntryLoc = DebugLoc::get(SP->getScopeLine(), 0, SP);
     // Keep static allocas and llvm.localescape calls in the entry block.  Even
     // if we aren't splitting the block, it's nice for allocas to be before

lib/Transforms/Utils/AddDiscriminators.cpp

@@ -99,11 +99,6 @@ FunctionPass *llvm::createAddDiscriminatorsPass() {
   return new AddDiscriminators();
 }
 
-static bool hasDebugInfo(const Function &F) {
-  DISubprogram *S = getDISubprogram(&F);
-  return S != nullptr;
-}
-
 /// \brief Assign DWARF discriminators.
 ///
 /// To assign discriminators, we examine the boundaries of every
@@ -161,7 +156,7 @@ bool AddDiscriminators::runOnFunction(Function &F) {
   // Simlarly, if the function has no debug info, do nothing.
   // Finally, if this module is built with dwarf versions earlier than 4,
   // do nothing (discriminator support is a DWARF 4 feature).
-  if (NoDiscriminators || !hasDebugInfo(F) ||
+  if (NoDiscriminators || !F.getSubprogram() ||
       F.getParent()->getDwarfVersion() < 4)
     return false;
 

test/Transforms/AddDiscriminators/call.ll

@@ -8,7 +8,7 @@
 ; #5 }
 
 ; Function Attrs: uwtable
-define void @_Z3foov() #0 {
+define void @_Z3foov() #0 !dbg !4 {
   call void @_Z3barv(), !dbg !10
 ; CHECK:  call void @_Z3barv(), !dbg ![[CALL0:[0-9]+]]
   call void @_Z3barv(), !dbg !11