Make getEntryIDForSymbol() return optional and address review comments

Author: Ash Dobrescu

bolt/include/bolt/Core/BinaryFunction.h

@@ -650,7 +650,8 @@ class BinaryFunction {
   ///
   /// Prefer to use BinaryContext::getFunctionForSymbol(EntrySymbol, &ID)
   /// instead of calling this function directly.
-  uint64_t getEntryIDForSymbol(const MCSymbol *EntrySymbol) const;
+  std::optional<uint64_t>
+  getEntryIDForSymbol(const MCSymbol *EntrySymbol) const;
 
   /// If the function represents a secondary split function fragment, set its
   /// parent fragment to \p BF.

bolt/lib/Core/BinaryContext.cpp

@@ -2378,11 +2378,10 @@ BinaryFunction *BinaryContext::getFunctionForSymbol(const MCSymbol *Symbol,
     const uint64_t Address = BF->getAddress() + Symbol->getOffset();
     if (BF->isInConstantIsland(Address)) {
       this->outs() << "BOLT-WARNING: symbol " << Symbol->getName()
-                   << " is in data region of function 0x"
-                   << Twine::utohexstr(BF->getAddress()) << ".\n";
-      return nullptr;
+                   << " is in data region of function " << BF->getOneName()
+                   << "(0x" << Twine::utohexstr(BF->getAddress()) << ").\n";
     }
-    *EntryDesc = BF->getEntryIDForSymbol(Symbol);
+    *EntryDesc = BF->getEntryIDForSymbol(Symbol).value_or(0);
   }
 
   return BF;

bolt/lib/Core/BinaryFunction.cpp

@@ -3855,7 +3855,8 @@ MCSymbol *BinaryFunction::getSymbolForEntryID(uint64_t EntryID) {
   return nullptr;
 }
 
-uint64_t BinaryFunction::getEntryIDForSymbol(const MCSymbol *Symbol) const {
+std::optional<uint64_t>
+BinaryFunction::getEntryIDForSymbol(const MCSymbol *Symbol) const {
   if (!isMultiEntry())
     return 0;
 
@@ -3882,8 +3883,7 @@ uint64_t BinaryFunction::getEntryIDForSymbol(const MCSymbol *Symbol) const {
       return NumEntries;
     ++NumEntries;
   }
-
-  llvm_unreachable("symbol not found");
+  return std::nullopt;
 }
 
 bool BinaryFunction::forEachEntryPoint(EntryPointCallbackTy Callback) const {

bolt/test/AArch64/check-symbol-area.s

@@ -12,38 +12,26 @@
 # CHECK-NOT: UNREACHABLE
 
 // Now BOLT throws a warning and does not crash.
-# CHECK: BOLT-WARNING: symbol [[SYM:.*]]  is in data region of function 0x{{.*}}.
+# CHECK: BOLT-WARNING: symbol third_block/1  is in data region of function first_block(0x{{[0-9a-f]+}}).
 
 .text
 .global main
 main:
-        stp     x14, x15, [sp, -8]!
-        mov     x14, sp
-        adrp    x1, .test
-        add     x0, x1, :lo12:.test
+        add     x0, x1, x1
         bl      first_block
         ret
 
 .global first_block
 $d:
 first_block:
-        stp     x14, x15, [sp, -8]!
-        mov     x14, sp
+        add     x0, x1, x1
         bl      second_block
         ret
 second_block:
-        stp     x14, x15, [sp, -8]!
-        mov     x14, sp
+        add     x0, x1, x1
         bl      third_block
         ret
 $x:
 third_block:
-        stp     x14, x15, [sp, -8]!
-        mov     x14, sp
-        adrp    x1, .data
-        add     x0, x1, :lo12:.test
+        add     x0, x1, x1
         ret
-
-.data
-.test:
-        .string "test"