[PATCH] D138362: [AsmPrinter] .addrsig_sym: remove isTransitiveUsedByMetadataOnly

[Fangrui Song via Phabricator via llvm-commits]

MaskRay created this revision.
MaskRay added reviewers: rnk, zequanwu.
Herald added subscribers: StephenFan, pengfei, hiraditya.
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With D135642 <https://reviews.llvm.org/D135642> ignoring unregistered symbols, isTransitiveUsedByMetadataOnly added
by D101512 <https://reviews.llvm.org/D101512> is no longer needed (the operation is potentially slow). There is a
`.addrsig_sym` directive for an only-used-by-metadata symbol but it does not
emit an entry.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D138362

Files:
  llvm/include/llvm/IR/Value.h
  llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
  llvm/lib/IR/Value.cpp
  llvm/test/CodeGen/X86/addrsig.ll


Index: llvm/test/CodeGen/X86/addrsig.ll
===================================================================
--- llvm/test/CodeGen/X86/addrsig.ll
+++ llvm/test/CodeGen/X86/addrsig.ll
@@ -1,8 +1,18 @@
 ; RUN: llc < %s -mtriple=x86_64-unknown-linux | FileCheck --check-prefix=NO-ADDRSIG %s
 ; RUN: llc < %s -mtriple=x86_64-unknown-linux -addrsig | FileCheck %s
+; RUN: llc %s -filetype=obj -mtriple=x86_64-unknown-linux -addrsig -o %t
+; RUN: llvm-readobj --addrsig %t | FileCheck %s --check-prefix=SYM
 
 ; NO-ADDRSIG-NOT: .addrsig
 
+; SYM:      Addrsig [
+; SYM-NEXT:   Sym: f1
+; SYM-NEXT:   Sym: metadata_f2
+; SYM-NEXT:   Sym: g1
+; SYM-NEXT:   Sym: a1
+; SYM-NEXT:   Sym: i1
+; SYM-NEXT: ]
+
 ; CHECK: .addrsig
 
 ; CHECK: .addrsig_sym f1
@@ -27,7 +37,8 @@
 
 declare void @f4(i8*) unnamed_addr
 
-; CHECK-NOT: .addrsig_sym metadata_f1
+;; f1 is unreferenced, so this directive does not emit an entry.
+; CHECK: .addrsig_sym metadata_f1
 declare void @metadata_f1()
 
 ; CHECK: .addrsig_sym metadata_f2
Index: llvm/lib/IR/Value.cpp
===================================================================
--- llvm/lib/IR/Value.cpp
+++ llvm/lib/IR/Value.cpp
@@ -1022,22 +1022,6 @@
   return Alloca->isSwiftError();
 }
 
-bool Value::isTransitiveUsedByMetadataOnly() const {
-  SmallVector<const User *, 32> WorkList(user_begin(), user_end());
-  SmallPtrSet<const User *, 32> Visited(user_begin(), user_end());
-  while (!WorkList.empty()) {
-    const User *U = WorkList.pop_back_val();
-    // If it is transitively used by a global value or a non-constant value,
-    // it's obviously not only used by metadata.
-    if (!isa<Constant>(U) || isa<GlobalValue>(U))
-      return false;
-    for (const User *UU : U->users())
-      if (Visited.insert(UU).second)
-        WorkList.push_back(UU);
-  }
-  return true;
-}
-
 //===----------------------------------------------------------------------===//
 //                             ValueHandleBase Class
 //===----------------------------------------------------------------------===//
Index: llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
===================================================================
--- llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -2261,9 +2261,9 @@
     // Emit address-significance attributes for all globals.
     OutStreamer->emitAddrsig();
     for (const GlobalValue &GV : M.global_values()) {
-      if (!GV.use_empty() && !GV.isTransitiveUsedByMetadataOnly() &&
-          !GV.isThreadLocal() && !GV.hasDLLImportStorageClass() &&
-          !GV.getName().startswith("llvm.") && !GV.hasAtLeastLocalUnnamedAddr())
+      if (!GV.use_empty() && !GV.isThreadLocal() &&
+          !GV.hasDLLImportStorageClass() && !GV.getName().startswith("llvm.") &&
+          !GV.hasAtLeastLocalUnnamedAddr())
         OutStreamer->emitAddrsigSym(getSymbol(&GV));
     }
   }
Index: llvm/include/llvm/IR/Value.h
===================================================================
--- llvm/include/llvm/IR/Value.h
+++ llvm/include/llvm/IR/Value.h
@@ -556,9 +556,6 @@
   /// Return true if there is metadata referencing this value.
   bool isUsedByMetadata() const { return IsUsedByMD; }
 
-  // Return true if this value is only transitively referenced by metadata.
-  bool isTransitiveUsedByMetadataOnly() const;
-
 protected:
   /// Get the current metadata attachments for the given kind, if any.
   ///


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