[BPF] Narrow some interfaces

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

Reviewed By: ajwerner

Differential Revision: https://reviews.llvm.org/D156443

Author: tamird

llvm/lib/Target/BPF/BTFDebug.cpp

@@ -973,8 +973,7 @@ void BTFDebug::visitMapDefType(const DIType *Ty, uint32_t &TypeId) {
 }
 
 /// 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())
@@ -1005,9 +1004,9 @@ std::string BTFDebug::populateFileContent(const DISubprogram *SP) {
   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;
@@ -1374,7 +1373,7 @@ void BTFDebug::beginInstruction(const MachineInstr *MI) {
     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;
     }
 
@@ -1386,8 +1385,7 @@ void BTFDebug::beginInstruction(const MachineInstr *MI) {
   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;

llvm/lib/Target/BPF/BTFDebug.h

@@ -341,12 +341,12 @@ class BTFDebug : public DebugHandlerBase {
   /// 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.