[llvm-nm]Add support for --no-demangle

GNU nm has --no-demangle, so llvm-nm should too. It disables the
--demangle switch. The patch also allows --demangle to be specified
multiple times (the last of all --no-demangle/--demangle switches
takes precedence).

Reviewed by: grimar, rupprecht, mattd

Differential Revision: https://reviews.llvm.org/D60134

llvm-svn: 357575

llvm/test/tools/llvm-nm/X86/demangle.ll

@@ -1,5 +1,6 @@
 ; RUN: llc -filetype=obj -mtriple=x86_64-pc-linux -o %t.o %s
 ; RUN: llvm-nm %t.o | FileCheck --check-prefix="MANGLED" %s
+; RUN: llvm-nm %t.o --no-demangle | FileCheck --check-prefix="MANGLED" %s
 ; RUN: llvm-nm -C %t.o | FileCheck --check-prefix="DEMANGLED" %s
 ; RUN: llvm-nm --demangle %t.o | FileCheck --check-prefix="DEMANGLED" %s
 
@@ -11,6 +12,12 @@
 ; RUN: llvm-nm %t.coff | FileCheck --check-prefix="COFF-MANGLED" %s
 ; RUN: llvm-nm -C %t.coff | FileCheck --check-prefix="COFF-DEMANGLED" %s
 
+; Show that the last of --no-demangle/--demangle wins:
+; RUN: llvm-nm --demangle --no-demangle %t.o | FileCheck --check-prefix="MANGLED" %s
+; RUN: llvm-nm --no-demangle --demangle %t.o | FileCheck --check-prefix="DEMANGLED" %s
+; RUN: llvm-nm --no-demangle --demangle --no-demangle %t.o | FileCheck --check-prefix="MANGLED" %s
+; RUN: llvm-nm --demangle --no-demangle --demangle %t.o | FileCheck --check-prefix="DEMANGLED" %s
+
 define i32 @_Z3fooi(i32) #0 {
 entry:
   ret i32 1

llvm/tools/llvm-nm/llvm-nm.cpp

@@ -124,9 +124,12 @@ cl::opt<bool> NoSort("no-sort", cl::desc("Show symbols in order encountered"));
 cl::alias NoSortp("p", cl::desc("Alias for --no-sort"), cl::aliasopt(NoSort),
                   cl::Grouping);
 
-cl::opt<bool> Demangle("demangle", cl::desc("Demangle C++ symbol names"));
-cl::alias DemangleC("C", cl::desc("Alias for --demangle"), cl::aliasopt(Demangle),
-                    cl::Grouping);
+cl::opt<bool> Demangle("demangle", cl::ZeroOrMore,
+                       cl::desc("Demangle C++ symbol names"));
+cl::alias DemangleC("C", cl::desc("Alias for --demangle"),
+                    cl::aliasopt(Demangle), cl::Grouping);
+cl::opt<bool> NoDemangle("no-demangle", cl::init(false), cl::ZeroOrMore,
+                         cl::desc("Don't demangle symbol names"));
 
 cl::opt<bool> ReverseSort("reverse-sort", cl::desc("Sort in reverse order"));
 cl::alias ReverseSortr("r", cl::desc("Alias for --reverse-sort"),
@@ -2106,6 +2109,10 @@ int main(int argc, char **argv) {
   if (InputFilenames.size() > 1)
     MultipleFiles = true;
 
+  // If both --demangle and --no-demangle are specified then pick the last one.
+  if (NoDemangle.getPosition() > Demangle.getPosition())
+    Demangle = !NoDemangle;
+
   for (unsigned i = 0; i < ArchFlags.size(); ++i) {
     if (ArchFlags[i] == "all") {
       ArchAll = true;