[llvm-size] Implement --common option

Differential Revision: http://reviews.llvm.org/D16820

llvm-svn: 264591

llvm/tools/llvm-size/llvm-size.cpp

@@ -57,6 +57,12 @@ cl::opt<bool>
 DarwinLongFormat("l", cl::desc("When format is darwin, use long format "
                                "to include addresses and offsets."));
 
+cl::opt<bool>
+    ELFCommons("common",
+               cl::desc("Print common symbols in the ELF file.  When using "
+                        "Berkely format, this is added to bss."),
+               cl::init(false));
+
 static cl::list<std::string>
 ArchFlags("arch", cl::desc("architecture(s) from a Mach-O file to dump"),
           cl::ZeroOrMore);
@@ -127,6 +133,15 @@ static bool considerForSize(ObjectFile *Obj, SectionRef Section) {
   return true;
 }
 
+/// Total size of all ELF common symbols
+static uint64_t getCommonSize(ObjectFile *Obj) {
+  uint64_t TotalCommons = 0;
+  for (auto &Sym : Obj->symbols())
+    if (Obj->getSymbolFlags(Sym.getRawDataRefImpl()) & SymbolRef::SF_Common)
+      TotalCommons += Obj->getCommonSymbolSize(Sym.getRawDataRefImpl());
+  return TotalCommons;
+}
+
 /// Print the size of each Mach-O segment and section in @p MachO.
 ///
 /// This is when used when @c OutputFormat is darwin and produces the same
@@ -352,6 +367,13 @@ static void printObjectSectionSizes(ObjectFile *Obj) {
       outs() << format(fmt.str().c_str(), namestr.c_str(), size, addr);
     }
 
+    if (ELFCommons) {
+      uint64_t CommonSize = getCommonSize(Obj);
+      total += CommonSize;
+      outs() << format(fmt.str().c_str(), std::string("*COM*").c_str(),
+                       CommonSize, static_cast<uint64_t>(0));
+    }
+
     // Print total.
     fmtbuf.clear();
     fmt << "%-" << max_name_len << "s "
@@ -379,6 +401,9 @@ static void printObjectSectionSizes(ObjectFile *Obj) {
         total_bss += size;
     }
 
+    if (ELFCommons)
+      total_bss += getCommonSize(Obj);
+
     total = total_text + total_data + total_bss;
 
     if (!BerkeleyHeaderPrinted) {