[PATCH] D100567: BPF: emit debuginfo for Function of DeclRefExpr if requested

[Yonghong Song via Phabricator via cfe-commits]

yonghong-song updated this revision to Diff 337993.
yonghong-song added a comment.

- check Fn->getSubprogram() before emit debuginfo. This is consistent with EmitFuncDeclForCallSite() and is better than checking FD->isDefined() as we may hit multiple DeclRefExpr and all of them will go through emitting debuginfo.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D100567/new/

https://reviews.llvm.org/D100567

Files:
  clang/include/clang/Basic/TargetInfo.h
  clang/lib/Basic/Targets/BPF.h
  clang/lib/CodeGen/CGExpr.cpp
  clang/lib/Sema/SemaDecl.cpp
  clang/test/CodeGen/debug-info-extern-callback.c


Index: clang/test/CodeGen/debug-info-extern-callback.c
===================================================================
--- /dev/null
+++ clang/test/CodeGen/debug-info-extern-callback.c
@@ -0,0 +1,10 @@
+// RUN: %clang_cc1 -x c -debug-info-kind=limited -triple bpf-linux-gnu -emit-llvm %s -o - | FileCheck %s
+
+extern int do_work(int);
+long bpf_helper(void *callback_fn);
+long prog() {
+	    return bpf_helper(&do_work);
+}
+
+// CHECK: declare !dbg ![[FUNC:[0-9]+]] i32 @do_work(i32)
+// CHECK: ![[FUNC]] = !DISubprogram(name: "do_work"
Index: clang/lib/Sema/SemaDecl.cpp
===================================================================
--- clang/lib/Sema/SemaDecl.cpp
+++ clang/lib/Sema/SemaDecl.cpp
@@ -12667,7 +12667,7 @@
         Diag(Var->getLocation(), diag::note_private_extern);
       }
 
-      if (Context.getTargetInfo().allowDebugInfoForExternalVar() &&
+      if (Context.getTargetInfo().allowDebugInfoForExternalRef() &&
           !Var->isInvalidDecl() && !getLangOpts().CPlusPlus)
         ExternalDeclarations.push_back(Var);
 
Index: clang/lib/CodeGen/CGExpr.cpp
===================================================================
--- clang/lib/CodeGen/CGExpr.cpp
+++ clang/lib/CodeGen/CGExpr.cpp
@@ -2834,8 +2834,20 @@
     return LV;
   }
 
-  if (const auto *FD = dyn_cast<FunctionDecl>(ND))
-    return EmitFunctionDeclLValue(*this, E, FD);
+  if (const auto *FD = dyn_cast<FunctionDecl>(ND)) {
+    LValue LV = EmitFunctionDeclLValue(*this, E, FD);
+
+    // Emit debuginfo for the function declaration if the target wants to.
+    if (getContext().getTargetInfo().allowDebugInfoForExternalRef()) {
+      auto *Fn = dyn_cast<llvm::Function>(LV.getPointer(*this));
+      if (!Fn->getSubprogram()) {
+        CGM.getModuleDebugInfo()->EmitFunctionDecl(FD, FD->getLocation(),
+                                                   T, Fn);
+      }
+    }
+
+    return LV;
+  }
 
   // FIXME: While we're emitting a binding from an enclosing scope, all other
   // DeclRefExprs we see should be implicitly treated as if they also refer to
Index: clang/lib/Basic/Targets/BPF.h
===================================================================
--- clang/lib/Basic/Targets/BPF.h
+++ clang/lib/Basic/Targets/BPF.h
@@ -76,7 +76,7 @@
     return None;
   }
 
-  bool allowDebugInfoForExternalVar() const override { return true; }
+  bool allowDebugInfoForExternalRef() const override { return true; }
 
   CallingConvCheckResult checkCallingConvention(CallingConv CC) const override {
     switch (CC) {
Index: clang/include/clang/Basic/TargetInfo.h
===================================================================
--- clang/include/clang/Basic/TargetInfo.h
+++ clang/include/clang/Basic/TargetInfo.h
@@ -1538,8 +1538,8 @@
 
   virtual void setAuxTarget(const TargetInfo *Aux) {}
 
-  /// Whether target allows debuginfo types for decl only variables.
-  virtual bool allowDebugInfoForExternalVar() const { return false; }
+  /// Whether target allows debuginfo types for decl only variables/functions.
+  virtual bool allowDebugInfoForExternalRef() const { return false; }
 
 protected:
   /// Copy type and layout related info.


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