[llvm] [ELFObject] Added dbgs() statement in removeSections() (PR #124692)

Kshitij Paranjape via llvm-commits llvm-commits at lists.llvm.org
Sat Feb 8 01:32:43 PST 2025


https://github.com/kshitijvp updated https://github.com/llvm/llvm-project/pull/124692

>From 718edfee71e995ab4fbee442af7b92a0c15cee65 Mon Sep 17 00:00:00 2001
From: Kshitij Paranjape <kshitijvparanjape at gmail.com>
Date: Mon, 27 Jan 2025 21:19:33 +0530
Subject: [PATCH 1/2] [ELFObject] Added dbgs() statement in removeSections()

This patch adds dbgs() statement inside removeSections()
and removeSymbol() function to print the removed sections
and symbols.

Fixes: #123041
---
 llvm/lib/ObjCopy/ELF/ELFObject.cpp    | 26 ++++++++++++++++++++------
 llvm/tools/llvm-objcopy/CommonOpts.td |  2 ++
 2 files changed, 22 insertions(+), 6 deletions(-)

diff --git a/llvm/lib/ObjCopy/ELF/ELFObject.cpp b/llvm/lib/ObjCopy/ELF/ELFObject.cpp
index 45c7ea49b5d938b..94c73b62de12e18 100644
--- a/llvm/lib/ObjCopy/ELF/ELFObject.cpp
+++ b/llvm/lib/ObjCopy/ELF/ELFObject.cpp
@@ -766,8 +766,14 @@ Error SymbolTableSection::removeSymbols(
     function_ref<bool(const Symbol &)> ToRemove) {
   Symbols.erase(
       std::remove_if(std::begin(Symbols) + 1, std::end(Symbols),
-                     [ToRemove](const SymPtr &Sym) { return ToRemove(*Sym); }),
-      std::end(Symbols));
+               [ToRemove](const SymPtr &Sym) {
+                   if (ToRemove(*Sym)) {
+                       dbgs()<<"Symbols Removed:"<<Sym->Name<< "\n";
+                       return true;
+                   }
+                   return false;
+               }));
+
   auto PrevSize = Size;
   Size = Symbols.size() * EntrySize;
   if (Size < PrevSize)
@@ -2249,10 +2255,18 @@ Error Object::removeSections(
 
   // Transfer removed sections into the Object RemovedSections container for use
   // later.
-  std::move(Iter, Sections.end(), std::back_inserter(RemovedSections));
-  // Now finally get rid of them all together.
-  Sections.erase(Iter, std::end(Sections));
-  return Error::success();
+  for(auto &KeepSec : make_range(std::begin(Sections) , Iter))
+  {
+    
+    if (Error E = KeepSec->removeSectionReferences(
+            AllowBrokenLinks, [&RemoveSections](const SectionBase *Sec) {
+              return RemoveSections.find(Sec) != RemoveSections.end();
+            }))
+      std::move(Iter, Sections.end(), std::back_inserter(RemovedSections));
+      dbgs()<<"Sections Removed:"<<KeepSec->Name<<'\n';
+      Sections.erase(Iter, std::end(Sections));
+      return Error::success();
+  }
 }
 
 Error Object::replaceSections(
diff --git a/llvm/tools/llvm-objcopy/CommonOpts.td b/llvm/tools/llvm-objcopy/CommonOpts.td
index c247c93f6e0f270..5b15191f546051a 100644
--- a/llvm/tools/llvm-objcopy/CommonOpts.td
+++ b/llvm/tools/llvm-objcopy/CommonOpts.td
@@ -117,6 +117,8 @@ def regex
 
 def version : Flag<["--"], "version">,
               HelpText<"Print the version and exit.">;
+def verbose : Flag<["--"], "verbose">,
+              HelpText<"Prints the removed symbols and sections">;
 def V : Flag<["-"], "V">,
         Alias<version>,
         HelpText<"Alias for --version">;

>From 02fb5c0b003a99cdbd36c47c2ffd1ca95ab5db85 Mon Sep 17 00:00:00 2001
From: Kshitij Paranjape <kshitijvparanjape at gmail.com>
Date: Sat, 8 Feb 2025 14:59:42 +0530
Subject: [PATCH 2/2] Made Changes

---
 llvm/include/llvm/ObjCopy/CommonConfig.h   |  1 +
 llvm/lib/ObjCopy/ELF/ELFObjcopy.cpp        |  1 +
 llvm/lib/ObjCopy/ELF/ELFObject.cpp         | 27 +++++++++++-----------
 llvm/lib/ObjCopy/ELF/ELFObject.h           |  1 +
 llvm/tools/llvm-objcopy/ObjcopyOptions.cpp |  2 ++
 5 files changed, 18 insertions(+), 14 deletions(-)

diff --git a/llvm/include/llvm/ObjCopy/CommonConfig.h b/llvm/include/llvm/ObjCopy/CommonConfig.h
index aea9cd6f9a9c72b..83ad4590d9c72cb 100644
--- a/llvm/include/llvm/ObjCopy/CommonConfig.h
+++ b/llvm/include/llvm/ObjCopy/CommonConfig.h
@@ -274,6 +274,7 @@ struct CommonConfig {
   bool StripNonAlloc = false;
   bool StripSections = false;
   bool StripUnneeded = false;
+  bool Verbose = false;
   bool Weaken = false;
   bool DecompressDebugSections = false;
 
diff --git a/llvm/lib/ObjCopy/ELF/ELFObjcopy.cpp b/llvm/lib/ObjCopy/ELF/ELFObjcopy.cpp
index 5aa0079f3fbc7a7..ad3a2135d23a753 100644
--- a/llvm/lib/ObjCopy/ELF/ELFObjcopy.cpp
+++ b/llvm/lib/ObjCopy/ELF/ELFObjcopy.cpp
@@ -782,6 +782,7 @@ static Error verifyNoteSection(StringRef Name, endianness Endianness,
 // system. The only priority is that keeps/copies overrule removes.
 static Error handleArgs(const CommonConfig &Config, const ELFConfig &ELFConfig,
                         ElfType OutputElfType, Object &Obj) {
+  Obj.isVerboseEnabled = Config.Verbose;
   if (Config.OutputArch) {
     Obj.Machine = Config.OutputArch->EMachine;
     Obj.OSABI = Config.OutputArch->OSABI;
diff --git a/llvm/lib/ObjCopy/ELF/ELFObject.cpp b/llvm/lib/ObjCopy/ELF/ELFObject.cpp
index 94c73b62de12e18..c9a090cdea51713 100644
--- a/llvm/lib/ObjCopy/ELF/ELFObject.cpp
+++ b/llvm/lib/ObjCopy/ELF/ELFObject.cpp
@@ -768,7 +768,7 @@ Error SymbolTableSection::removeSymbols(
       std::remove_if(std::begin(Symbols) + 1, std::end(Symbols),
                [ToRemove](const SymPtr &Sym) {
                    if (ToRemove(*Sym)) {
-                       dbgs()<<"Symbols Removed:"<<Sym->Name<< "\n";
+                       llvm::outs() << "Symbols Removed:" << Sym->Name<< "\n";
                        return true;
                    }
                    return false;
@@ -2236,6 +2236,9 @@ Error Object::removeSections(
   for (auto &RemoveSec : make_range(Iter, std::end(Sections))) {
     for (auto &Segment : Segments)
       Segment->removeSection(RemoveSec.get());
+    if (isVerboseEnabled) {
+      llvm::outs() << "Removed Section: " << (RemoveSec.get()->Name);
+    }
     RemoveSec->onRemove();
     RemoveSections.insert(RemoveSec.get());
   }
@@ -2255,18 +2258,10 @@ Error Object::removeSections(
 
   // Transfer removed sections into the Object RemovedSections container for use
   // later.
-  for(auto &KeepSec : make_range(std::begin(Sections) , Iter))
-  {
-    
-    if (Error E = KeepSec->removeSectionReferences(
-            AllowBrokenLinks, [&RemoveSections](const SectionBase *Sec) {
-              return RemoveSections.find(Sec) != RemoveSections.end();
-            }))
-      std::move(Iter, Sections.end(), std::back_inserter(RemovedSections));
-      dbgs()<<"Sections Removed:"<<KeepSec->Name<<'\n';
-      Sections.erase(Iter, std::end(Sections));
-      return Error::success();
-  }
+  std::move(Iter, Sections.end(), std::back_inserter(RemovedSections));
+  // Now finally get rid of them all together.
+  Sections.erase(Iter, std::end(Sections));
+  return Error::success();
 }
 
 Error Object::replaceSections(
@@ -2296,8 +2291,12 @@ Error Object::replaceSections(
 Error Object::removeSymbols(function_ref<bool(const Symbol &)> ToRemove) {
   if (SymbolTable)
     for (const SecPtr &Sec : Sections)
-      if (Error E = Sec->removeSymbols(ToRemove))
+      if (Error E = Sec->removeSymbols(ToRemove)){
+        if (isVerboseEnabled){
+          llvm::outs() << "Removed Symbols:" << Sec->Name;
+        }
         return E;
+      }
   return Error::success();
 }
 
diff --git a/llvm/lib/ObjCopy/ELF/ELFObject.h b/llvm/lib/ObjCopy/ELF/ELFObject.h
index d8f79a4b1a3cc6e..4ec1f7188ef88a5 100644
--- a/llvm/lib/ObjCopy/ELF/ELFObject.h
+++ b/llvm/lib/ObjCopy/ELF/ELFObject.h
@@ -1195,6 +1195,7 @@ class Object {
   uint32_t Flags;
 
   bool HadShdrs = true;
+  bool isVerboseEnabled = true;
   bool MustBeRelocatable = false;
   StringTableSection *SectionNames = nullptr;
   SymbolTableSection *SymbolTable = nullptr;
diff --git a/llvm/tools/llvm-objcopy/ObjcopyOptions.cpp b/llvm/tools/llvm-objcopy/ObjcopyOptions.cpp
index 0d209590655ef36..7a0d7197560818d 100644
--- a/llvm/tools/llvm-objcopy/ObjcopyOptions.cpp
+++ b/llvm/tools/llvm-objcopy/ObjcopyOptions.cpp
@@ -1103,6 +1103,7 @@ objcopy::parseObjcopyOptions(ArrayRef<const char *> ArgsArr,
       OBJCOPY_verify_note_sections, OBJCOPY_no_verify_note_sections, true);
 
   Config.OnlyKeepDebug = InputArgs.hasArg(OBJCOPY_only_keep_debug);
+  Config.Verbose = InputArgs.hasArg(OBJCOPY_verbose);
   ELFConfig.KeepFileSymbols = InputArgs.hasArg(OBJCOPY_keep_file_symbols);
   MachOConfig.KeepUndefined = InputArgs.hasArg(OBJCOPY_keep_undefined);
   Config.DecompressDebugSections =
@@ -1586,6 +1587,7 @@ objcopy::parseStripOptions(ArrayRef<const char *> RawArgsArr,
   Config.StripAllGNU = InputArgs.hasArg(STRIP_strip_all_gnu);
   MachOConfig.StripSwiftSymbols = InputArgs.hasArg(STRIP_strip_swift_symbols);
   Config.OnlyKeepDebug = InputArgs.hasArg(STRIP_only_keep_debug);
+  Config.Verbose = InputArgs.hasArg(STRIP_verbose);
   ELFConfig.KeepFileSymbols = InputArgs.hasArg(STRIP_keep_file_symbols);
   MachOConfig.KeepUndefined = InputArgs.hasArg(STRIP_keep_undefined);
 



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