[llvm] r328820 - For llvm-nm and Mach-O files that are fully stripped, special case a redacted LC_MAIN

[Kevin Enderby via llvm-commits]

Author: enderby
Date: Thu Mar 29 13:04:29 2018
New Revision: 328820

URL: http://llvm.org/viewvc/llvm-project?rev=328820&view=rev
Log:
For llvm-nm and Mach-O files that are fully stripped, special case a redacted LC_MAIN

As a further refinement on:

r328274 - For llvm-nm and Mach-O files also use function starts info in some cases when printing symbols

we want to special case a redacted LC_MAIN so it is easier to find.

rdar://38978929

Added:
    llvm/trunk/test/tools/llvm-nm/X86/Inputs/Strip-N.LC_MAIN.exe.macho-x86_64   (with props)
Modified:
    llvm/trunk/test/tools/llvm-nm/X86/dyldinfo.test
    llvm/trunk/tools/llvm-nm/llvm-nm.cpp

Added: llvm/trunk/test/tools/llvm-nm/X86/Inputs/Strip-N.LC_MAIN.exe.macho-x86_64
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/tools/llvm-nm/X86/Inputs/Strip-N.LC_MAIN.exe.macho-x86_64?rev=328820&view=auto
==============================================================================
Binary file - no diff available.

Propchange: llvm/trunk/test/tools/llvm-nm/X86/Inputs/Strip-N.LC_MAIN.exe.macho-x86_64
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    svn:executable = *

Propchange: llvm/trunk/test/tools/llvm-nm/X86/Inputs/Strip-N.LC_MAIN.exe.macho-x86_64
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    svn:mime-type = application/octet-stream

Modified: llvm/trunk/test/tools/llvm-nm/X86/dyldinfo.test
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/tools/llvm-nm/X86/dyldinfo.test?rev=328820&r1=328819&r2=328820&view=diff
==============================================================================
--- llvm/trunk/test/tools/llvm-nm/X86/dyldinfo.test (original)
+++ llvm/trunk/test/tools/llvm-nm/X86/dyldinfo.test Thu Mar 29 13:04:29 2018
@@ -2,6 +2,7 @@
 # RUN: llvm-nm -no-dyldinfo %p/Inputs/Strip-ST.dylib.macho-x86_64 | FileCheck --check-prefix=NO-DYLDINFO %s
 # RUN: llvm-nm -dyldinfo-only %p/Inputs/Strip-ST.dylib.macho-x86_64 | FileCheck --check-prefix=DYLDINFO-ONLY %s
 # RUN: llvm-nm %p/Inputs/Strip-N.hello.exe.macho-x86_64 | FileCheck --check-prefix=FUNC-STARTS %s
+# RUN: llvm-nm %p/Inputs/Strip-N.LC_MAIN.exe.macho-x86_64 | FileCheck --check-prefix=LC-MAIN %s
 
 # DEFAULT: 0000000000000f90 T __Bob_is_slow
 # DEFAULT: 0000000000001008 D __T0ims_data
@@ -24,3 +25,8 @@
 # FUNC-STARTS: 0000000100000f30 T _main
 # FUNC-STARTS: U _printf
 # FUNC-STARTS: U dyld_stub_binder
+
+# LC-MAIN: 0000000100000f50 t <redacted LC_MAIN>
+# LC-MAIN: 0000000100000000 T __mh_execute_header
+# LC-MAIN:                  U _printf
+# LC-MAIN:                  U dyld_stub_binder

Modified: llvm/trunk/tools/llvm-nm/llvm-nm.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/llvm-nm/llvm-nm.cpp?rev=328820&r1=328819&r2=328820&view=diff
==============================================================================
--- llvm/trunk/tools/llvm-nm/llvm-nm.cpp (original)
+++ llvm/trunk/tools/llvm-nm/llvm-nm.cpp Thu Mar 29 13:04:29 2018
@@ -1588,8 +1588,10 @@ dumpSymbolNamesFromObject(SymbolicFile &
         }
       }
 
-      // Trying adding symbol from the function starts table.
+      // Trying adding symbol from the function starts table and LC_MAIN entry
+      // point.
       SmallVector<uint64_t, 8> FoundFns;
+      int64_t lc_main_offset = -1;
       for (const auto &Command : MachO->load_commands()) {
         if (Command.C.cmd == MachO::LC_FUNCTION_STARTS) {
           // We found a function starts segment, parse the addresses for 
@@ -1598,6 +1600,10 @@ dumpSymbolNamesFromObject(SymbolicFile &
             MachO->getLinkeditDataLoadCommand(Command);
 
           MachO->ReadULEB128s(LLC.dataoff, FoundFns);
+        } else if (Command.C.cmd == MachO::LC_MAIN) {
+          MachO::entry_point_command LCmain =
+            MachO->getEntryPointCommand(Command);
+          lc_main_offset = LCmain.entryoff;
         }
       }
       // See if these addresses are already in the symbol table.
@@ -1647,7 +1653,10 @@ dumpSymbolNamesFromObject(SymbolicFile &
           F.NDesc = 0;
           F.IndirectName = StringRef();
           SymbolList.push_back(F);
-          FOS << "<redacted function " << f << ">";
+          if (FoundFns[f] == (uint64_t)lc_main_offset)
+            FOS << "<redacted LC_MAIN>";
+          else
+            FOS << "<redacted function " << f << ">";
           FOS << '\0';
           FunctionStartsAdded++;
         }