[clang] (New) Add option to generate additional debug info for expression dereferencing pointer to pointers (PR #95298)

[Jeremy Morse via cfe-commits]

================
@@ -5746,6 +5746,57 @@ void CGDebugInfo::EmitExternalVariable(llvm::GlobalVariable *Var,
   Var->addDebugInfo(GVE);
 }
 
+void CGDebugInfo::EmitPseudoVariable(CGBuilderTy &Builder,
+                                     llvm::Instruction *Value, QualType Ty) {
+  // Only when -g2 or above is specified, debug info for variables will be
+  // generated.
+  if (CGM.getCodeGenOpts().getDebugInfo() <=
+      llvm::codegenoptions::DebugLineTablesOnly)
+    return;
+
+  llvm::DILocation *DIL = Value->getDebugLoc().get();
+  if (!DIL)
+    return;
+
+  llvm::DIFile *Unit = DIL->getFile();
+  llvm::DIType *Type = getOrCreateType(Ty, Unit);
+
+  // Check if Value is already a declared variable and has debug info, in this
+  // case we have nothing to do. Clang emits declared variable as alloca, and
----------------
jmorse wrote:

```suggestion
  // case we have nothing to do. Clang emits declared variable as alloca, and
```
```suggestion
  // case we have nothing to do. Clang emits declared variables as alloca, and
```

https://github.com/llvm/llvm-project/pull/95298