[BPF] Narrow some interfaces

[tamird]

Summary

When compiling Rust code we sometimes see incomplete debug info leading
to crashes. Narrow the interfaces so we can see where it happens.

[tamird]

Split commits into separate diffs.

[tamird]

Rebase

[ajwerner]

LGTM

[ast]

what ? Please revert asap. The code wasn't approved by maintainers.

[tamird]

In D156443#4554934, @ast wrote:

what ? Please revert asap. The code wasn't approved by maintainers.

Please help me understand how to work with you. I'm happy to revert this in service of cultivating a working relationship. How can I get engagement from you folks in a reasonable period of time? This was sent on July 27 and does not change behavior.

Regarding maintainers: where is the list of maintainers please?

[ast]

In D156443#4554941, @tamird wrote:

In D156443#4554934, @ast wrote:

what ? Please revert asap. The code wasn't approved by maintainers.

Please help me understand how to work with you. I'm happy to revert this in service of cultivating a working relationship. How can I get engagement from you folks in a reasonable period of time? This was sent on July 27 and does not change behavior.

Regarding maintainers: where is the list of maintainers please?

Revert and don't land without explicit approval by me or Yonghong.

[tamird]

Reverted. Please review.

[ast]

I'm fed up with these pointless cleanups.

@tamird, new rules specifically for you:

1. no selftest = auto-reject.

You must demonstrate the bug with the test.

2. You must wait for both myself and @yonghong-song approvals before landing.

If you land it without approval again you will lose write permissions.

@ajwerner do not approve patches not in your area. If you want to express your opinion add a comment "lgtm" or something.

llvm/lib/Target/BPF/BTFDebug.h

class BTFDebug : public DebugHandlerBase {
   void visitDerivedType(const DIDerivedType *DTy, uint32_t &TypeId,
                         bool CheckPointer, bool SeenPointer);
   void visitMapDefType(const DIType *Ty, uint32_t &TypeId);
   /// @}
 
   /// Check whether the type is a forward declaration candidate or not.
   bool IsForwardDeclCandidate(const DIType *Base);
 
-  /// Get the file content for the subprogram. Certain lines of the file
+  /// Get the file content. Certain lines of the file
   /// later may be put into string table and referenced by line info.
-  std::string populateFileContent(const DISubprogram *SP);
+  std::string populateFileContent(const DIFile *File);
 
   /// Construct a line info.
-  void constructLineInfo(const DISubprogram *SP, MCSymbol *Label, uint32_t Line,
+  void constructLineInfo(const DIFile *File, MCSymbol *Label, uint32_t Line,
                          uint32_t Column);
 
   /// Generate types and variables for globals.
   void processGlobals(bool ProcessingMapDef);
 
   /// Generate types for function prototypes.
   void processFuncPrototypes(const Function *);
 

llvm/lib/Target/BPF/BTFDebug.cpp

for (const auto *Element : Elements) {
     visitTypeEntry(MemberType->getBaseType());
   }
 
   // Visit this type, struct or a const/typedef/volatile/restrict type
   visitTypeEntry(OrigTy, TypeId, false, false);
 }
 
 /// Read file contents from the actual file or from the source
-std::string BTFDebug::populateFileContent(const DISubprogram *SP) {
-  auto File = SP->getFile();
+std::string BTFDebug::populateFileContent(const DIFile *File) {
   std::string FileName;
 
   if (!File->getFilename().startswith("/") && File->getDirectory().size())
     FileName = File->getDirectory().str() + "/" + File->getFilename().str();
   else
     FileName = std::string(File->getFilename());
 
   // No need to populate the contends if it has been populated!
std::string BTFDebug::populateFileContent(const DIFile *File) {
   if (Buf)
     for (line_iterator I(*Buf, false), E; I != E; ++I)
       Content.push_back(std::string(*I));
 
   FileContent[FileName] = Content;
   return FileName;
 }
 
-void BTFDebug::constructLineInfo(const DISubprogram *SP, MCSymbol *Label,
+void BTFDebug::constructLineInfo(const DIFile *File, MCSymbol *Label,
                                  uint32_t Line, uint32_t Column) {
-  std::string FileName = populateFileContent(SP);
+  std::string FileName = populateFileContent(File);
   BTFLineInfo LineInfo;
 
   LineInfo.Label = Label;
   LineInfo.FileNameOff = addString(FileName);
   // If file content is not available, let LineOff = 0.
   if (Line < FileContent[FileName].size())
     LineInfo.LineOff = addString(FileContent[FileName][Line]);
   else
void BTFDebug::beginInstruction(const MachineInstr *MI) {
   // is the same as the previous instruction.
   const DebugLoc &DL = MI->getDebugLoc();
   if (!DL || PrevInstLoc == DL) {
     // This instruction will be skipped, no LineInfo has
     // been generated, construct one based on function signature.
     if (LineInfoGenerated == false) {
       auto *S = MI->getMF()->getFunction().getSubprogram();
       MCSymbol *FuncLabel = Asm->getFunctionBegin();
-      constructLineInfo(S, FuncLabel, S->getLine(), 0);
+      constructLineInfo(S->getFile(), FuncLabel, S->getLine(), 0);
       LineInfoGenerated = true;
     }
 
     return;
   }
 
   // Create a temporary label to remember the insn for lineinfo.
   MCSymbol *LineSym = OS.getContext().createTempSymbol();
   OS.emitLabel(LineSym);
 
   // Construct the lineinfo.
-  auto SP = DL->getScope()->getSubprogram();
-  constructLineInfo(SP, LineSym, DL.getLine(), DL.getCol());
+  constructLineInfo(DL->getFile(), LineSym, DL.getLine(), DL.getCol());
 
   LineInfoGenerated = true;
   PrevInstLoc = DL;
 }
 
 void BTFDebug::processGlobals(bool ProcessingMapDef) {
   // Collect all types referenced by globals.
   const Module *M = MMI->getModule();