Revert "[BOLT] Abort on out-of-section symbols in GOT (#100801)"

This reverts commit a4900f0.

Author: dcci

bolt/include/bolt/Core/BinaryContext.h

@@ -911,8 +911,7 @@ class BinaryContext {
   /// of \p Flags.
   MCSymbol *registerNameAtAddress(StringRef Name, uint64_t Address,
                                   uint64_t Size, uint16_t Alignment,
-                                  unsigned Flags = 0,
-                                  BinarySection *Section = NULL);
+                                  unsigned Flags = 0);
 
   /// Return BinaryData registered at a given \p Address or nullptr if no
   /// global symbol was registered at the location.

bolt/lib/Core/BinaryContext.cpp

@@ -1055,28 +1055,18 @@ void BinaryContext::adjustCodePadding() {
 MCSymbol *BinaryContext::registerNameAtAddress(StringRef Name, uint64_t Address,
                                                uint64_t Size,
                                                uint16_t Alignment,
-                                               unsigned Flags,
-                                               BinarySection *Section) {
+                                               unsigned Flags) {
   // Register the name with MCContext.
   MCSymbol *Symbol = Ctx->getOrCreateSymbol(Name);
-  BinaryData *BD;
-
-  // Register out of section symbols only in GlobalSymbols map
-  if (Section && Section->getEndAddress() == Address) {
-    BD = new BinaryData(*Symbol, Address, Size, Alignment ? Alignment : 1,
-                        *Section, Flags);
-    GlobalSymbols[Name] = BD;
-    return Symbol;
-  }
 
   auto GAI = BinaryDataMap.find(Address);
+  BinaryData *BD;
   if (GAI == BinaryDataMap.end()) {
     ErrorOr<BinarySection &> SectionOrErr = getSectionForAddress(Address);
-    BinarySection &SectionRef = Section        ? *Section
-                                : SectionOrErr ? SectionOrErr.get()
-                                               : absoluteSection();
+    BinarySection &Section =
+        SectionOrErr ? SectionOrErr.get() : absoluteSection();
     BD = new BinaryData(*Symbol, Address, Size, Alignment ? Alignment : 1,
-                        SectionRef, Flags);
+                        Section, Flags);
     GAI = BinaryDataMap.emplace(Address, BD).first;
     GlobalSymbols[Name] = BD;
     updateObjectNesting(GAI);
@@ -1411,7 +1401,7 @@ void BinaryContext::postProcessSymbolTable() {
     if ((BD->getName().starts_with("SYMBOLat") ||
          BD->getName().starts_with("DATAat")) &&
         !BD->getParent() && !BD->getSize() && !BD->isAbsolute() &&
-        BD->getSection().getSize()) {
+        BD->getSection()) {
       this->errs() << "BOLT-WARNING: zero-sized top level symbol: " << *BD
                    << "\n";
       Valid = false;

bolt/lib/Rewrite/RewriteInstance.cpp

@@ -956,13 +956,13 @@ void RewriteInstance::discoverFileObjects() {
     uint64_t SymbolSize = ELFSymbolRef(Symbol).getSize();
     uint64_t SymbolAlignment = Symbol.getAlignment();
 
-    auto registerName = [&](uint64_t FinalSize, BinarySection *Section = NULL) {
+    auto registerName = [&](uint64_t FinalSize) {
       // Register names even if it's not a function, e.g. for an entry point.
       BC->registerNameAtAddress(UniqueName, SymbolAddress, FinalSize,
-                                SymbolAlignment, SymbolFlags, Section);
+                                SymbolAlignment, SymbolFlags);
       if (!AlternativeName.empty())
         BC->registerNameAtAddress(AlternativeName, SymbolAddress, FinalSize,
-                                  SymbolAlignment, SymbolFlags, Section);
+                                  SymbolAlignment, SymbolFlags);
     };
 
     section_iterator Section =
@@ -987,25 +987,12 @@ void RewriteInstance::discoverFileObjects() {
                       << " for function\n");
 
     if (SymbolAddress == Section->getAddress() + Section->getSize()) {
-      ErrorOr<BinarySection &> SectionOrError =
-          BC->getSectionForAddress(Section->getAddress());
-
-      // Skip symbols from invalid sections
-      if (!SectionOrError) {
-        BC->errs() << "BOLT-WARNING: " << UniqueName << " (0x"
-                   << Twine::utohexstr(SymbolAddress)
-                   << ") does not have any section\n";
-        continue;
-      }
-
       assert(SymbolSize == 0 &&
              "unexpect non-zero sized symbol at end of section");
-      LLVM_DEBUG({
-        dbgs() << "BOLT-DEBUG: rejecting as symbol " << UniqueName
-               << " points to end of " << SectionOrError->getName()
-               << " section\n";
-      });
-      registerName(SymbolSize, &SectionOrError.get());
+      LLVM_DEBUG(
+          dbgs()
+          << "BOLT-DEBUG: rejecting as symbol points to end of its section\n");
+      registerName(SymbolSize);
       continue;
     }
 
@@ -2637,30 +2624,6 @@ void RewriteInstance::handleRelocation(const SectionRef &RelocatedSection,
     }
   }
 
-  if (Relocation::isGOT(RType) && !Relocation::isTLS(RType)) {
-    auto exitOnGotEndSymol = [&](StringRef Name) {
-      BC->errs() << "BOLT-ERROR: GOT table contains currently unsupported "
-                    "section end symbol "
-                 << Name << "\n";
-      exit(1);
-    };
-
-    if (SymbolIter != InputFile->symbol_end() && ReferencedSection) {
-      if (cantFail(SymbolIter->getAddress()) ==
-          ReferencedSection->getEndAddress())
-        exitOnGotEndSymol(cantFail(SymbolIter->getName()));
-    } else {
-      // If no section and symbol are provided by relocation, try to find the
-      // symbol by its name, including the possibility that the symbol is local.
-      BinaryData *BD = BC->getBinaryDataByName(SymbolName);
-      if (!BD && NR.getUniquifiedNameCount(SymbolName) == 1)
-        BD = BC->getBinaryDataByName(NR.getUniqueName(SymbolName, 1));
-
-      if ((BD && BD->getAddress() == BD->getSection().getEndAddress()))
-        exitOnGotEndSymol(BD->getName());
-    }
-  }
-
   if (!ReferencedSection)
     ReferencedSection = BC->getSectionForAddress(SymbolAddress);
 

bolt/test/AArch64/Inputs/got_end_of_section_symbol.lld_script

@@ -1,15 +1,15 @@
 ## Check that BOLT doesn't consider end-of-section symbols (e.g., _etext) as
 ## functions.
 
-# REQUIRES: system-linux, asserts
+# REQUIRES: x86_64-linux, asserts
 
 # RUN: llvm-mc -filetype=obj -triple x86_64-unknown-linux %s -o %t.o
 # RUN: ld.lld %t.o -o %t.exe -q
 # RUN: llvm-bolt %t.exe -o %t.null --print-cfg --debug-only=bolt 2>&1 \
 # RUN:   | FileCheck %s
 
 # CHECK: considering symbol etext for function
-# CHECK-NEXT: rejecting as symbol etext points to end of .text section
+# CHECK-NEXT: rejecting as symbol points to end of its section
 # CHECK-NOT: Binary Function "etext{{.*}}" after building cfg