[llvm-nm/objdump/size] Add tests for dumping symbol tables with invalid sh_size.

[Higuoxing]

Summary

This change adds tests for llvm-nm, llvm-objdump and llvm-size when dumping symbol tables with invalid sh_size (sh_size % sizeof(Elf_Sym) != 0).

[jhenderson]

llvm/test/tools/llvm-nm/invalid-symbol-table-size.test

2

will emit -> emits

(same in other tests)

llvm/test/tools/llvm-size/invalid-symbol-table-size.test

6

I think you need testing for both the sysv and berkeley output formats, as you've handled the error in two different places.

[grimar]

llvm/test/tools/llvm-nm/invalid-symbol-table-size.test

13

In this and other test cases you have 2 sections: .symtab and .dynsym, but only one section (with index 2)
is reported in error messages.

[Higuoxing]

llvm/test/tools/llvm-nm/invalid-symbol-table-size.test

13

Yes, because there are malformed .symtab and .dynsym symbol tables in one ELF file. And getSymbolFlags() checks .symtab first. See ELFObjectFile.h.

if (Expected<typename ELFT::SymRange> SymbolsOrErr =
        EF.symbols(DotSymtabSec)) {
  ...
} else
  // TODO: Test this error.
  return SymbolsOrErr.takeError();

if (Expected<typename ELFT::SymRange> SymbolsOrErr =
        EF.symbols(DotDynSymSec)) {
  ...
} else
  // TODO: Test this error.
  return SymbolsOrErr.takeError();

I think it's a good point, and it's helpful to report errors on our interested sections.

---

Currently, I have two approaches in mind.

1. We could add one more argument IsDynamic to getSymbolFlags(DataRefImpl Symb, bool IsDynamic=false). So that we can skip first checker if we've already known the symbol is a dynamic symbol. (Possible)

2. Change the return type of symbol iterator API from symbol_iterator to Expected<symbol_iterator>, so that we could get error reports earlier. (I didn't give it a try, and it seems involving many changes.)

[grimar]

llvm/test/tools/llvm-nm/invalid-symbol-table-size.test

13

Why not to change the test so that you have a one broken test at once?

Case 1: Broken .symtab. Valid .dynsym.
Case 2: Valid .symtab. Broken .dynsym.

13

• a one broken section

[Higuoxing]

llvm/test/tools/llvm-nm/invalid-symbol-table-size.test

13

I think change test cases partly resolve this problem. I mean, if we one broken .symtab, and a good .dynsym section, consider the following situation.

# broken .symtab prevents us dumping .dynsym
$ llvm-nm --dynamic broken-symtab.elf
$ llvm-objdump --dynamic-syms broken-symtab.elf

[grimar]

llvm/test/tools/llvm-nm/invalid-symbol-table-size.test

13

You can have

Case 3: Both .symtab and .dynsym are broken. The same behavior as in Case 1.

[Higuoxing]

llvm/test/tools/llvm-nm/invalid-symbol-table-size.test

13

Ok, thanks a lot.

[Higuoxing]

Addressed comments.

• Test .symtab and .dynsym separately.
• Add tests in llvm-size for different output format (sysv and berkeley).

[jhenderson]

LGTM! @grimar is away this week, I believe, so I don't think you need to wait for him.

llvm/test/tools/llvm-nm/invalid-symbol-table-size.test

+## This test ensures llvm-nm emits a helpful error message when dumping a symbol table
+## whose sh_size isn't a multiple of the symbol size (sh_size % sizeof(Elf_Sym) != 0).
+
+## a) Broken .symtab symbol table. Valid .dynsym symbol table.
+# RUN: yaml2obj -DBITS=32 -DSIZE=33 -DDYNSIZE=32 %s -o %t.32-bit.o
+# RUN: not llvm-nm %t.32-bit.o 2>&1 | FileCheck -DSIZE=33 -DSYMSIZE=16 -DINDEX=2 %s
+# RUN: yaml2obj -DBITS=64 -DSIZE=49 -DDYNSIZE=48 %s -o %t.64-bit.o
+# RUN: not llvm-nm %t.64-bit.o 2>&1 | FileCheck -DSIZE=49 -DSYMSIZE=24 -DINDEX=2 %s
+
+## b) Broken .dynsym symbol table. Valid .symtab symbol table.
+# RUN: yaml2obj -DBITS=32 -DSIZE=32 -DDYNSIZE=33 %s -o %t.32-bit.o
+# RUN: not llvm-nm --dynamic %t.32-bit.o 2>&1 | FileCheck -DSIZE=33 -DSYMSIZE=16 -DINDEX=3 %s
+# RUN: yaml2obj -DBITS=64 -DSIZE=48 -DDYNSIZE=49 %s -o %t.64-bit.o
+# RUN: not llvm-nm --dynamic %t.64-bit.o 2>&1 | FileCheck -DSIZE=49 -DSYMSIZE=24 -DINDEX=3 %s
+
+# CHECK: error: {{.*}} section [index [[INDEX]]] has an invalid sh_size ([[SIZE]]) which is not a multiple of its sh_entsize ([[SYMSIZE]])
+
+--- !ELF
+FileHeader:
+  Class:   ELFCLASS[[BITS]]
+  Data:    ELFDATA2LSB
+  Type:    ET_DYN
+  Machine: EM_X86_64
+Sections:
+  - Name:    .dynstr
+    Type:    SHT_STRTAB
+    Content: "00"
+  - Name:    .symtab
+    Type:    SHT_SYMTAB
+    Size:    [[SIZE]]
+  - Name:    .dynsym
+    Type:    SHT_DYNSYM
+    Size:    [[DYNSIZE]]

llvm/test/tools/llvm-objdump/invalid-symbol-table-size.test

+## This test ensures llvm-objdump emits a helpful error message when dumping a symbol table
+## whose sh_size isn't a multiple of the symbol size (sh_size % sizeof(Elf_Sym) != 0).
+
+## a) Broken .symtab symbol table. Valid .dynsym symbol table.
+# RUN: yaml2obj -DBITS=32 -DSIZE=33 -DDYNSIZE=32 %s -o %t.32-bit.o
+# RUN: not llvm-objdump --syms %t.32-bit.o 2>&1 | FileCheck -DSIZE=33 -DSYMSIZE=16 -DINDEX=2 %s
+# RUN: yaml2obj -DBITS=64 -DSIZE=49 -DDYNSIZE=48 %s -o %t.64-bit.o
+# RUN: not llvm-objdump --syms %t.64-bit.o 2>&1 | FileCheck -DSIZE=49 -DSYMSIZE=24 -DINDEX=2 %s
+
+## b) Broken .dynsym symbol table. Valid .symtab symbol table.
+# RUN: yaml2obj -DBITS=32 -DSIZE=32 -DDYNSIZE=33 %s -o %t.32-bit.o
+# RUN: not llvm-objdump --dynamic-syms %t.32-bit.o 2>&1 | FileCheck -DSIZE=33 -DSYMSIZE=16 -DINDEX=3 %s
+# RUN: yaml2obj -DBITS=64 -DSIZE=48 -DDYNSIZE=49 %s -o %t.64-bit.o
+# RUN: not llvm-objdump --dynamic-syms %t.64-bit.o 2>&1 | FileCheck -DSIZE=49 -DSYMSIZE=24 -DINDEX=3 %s
+
+# CHECK: error: {{.*}} section [index [[INDEX]]] has an invalid sh_size ([[SIZE]]) which is not a multiple of its sh_entsize ([[SYMSIZE]])
+
+--- !ELF
+FileHeader:
+  Class:   ELFCLASS[[BITS]]
+  Data:    ELFDATA2LSB
+  Type:    ET_DYN
+  Machine: EM_X86_64
+Sections:
+  - Name:    .dynstr
+    Type:    SHT_STRTAB
+    Content: "00"
+  - Name:    .symtab
+    Type:    SHT_SYMTAB
+    Size:    [[SIZE]]
+  - Name:    .dynsym
+    Type:    SHT_DYNSYM
+    Size:    [[DYNSIZE]]

llvm/test/tools/llvm-size/invalid-symbol-table-size.test

+## This test ensures llvm-size emits a helpful error message when dumping a symbol table
+## whose sh_size isn't a multiple of the symbol size (sh_size % sizeof(Elf_Sym) != 0).
+
+## a) Test sysv output format.
+# RUN: yaml2obj -DBITS=32 -DSIZE=33 -DDYNSIZE=32 %s -o %t.32-bit.o
+# RUN: not llvm-size --common --format=sysv %t.32-bit.o 2>&1 | FileCheck -DSIZE=33 -DSYMSIZE=16 %s
+# RUN: yaml2obj -DBITS=64 -DSIZE=49 -DDYNSIZE=48 %s -o %t.64-bit.o
+# RUN: not llvm-size --common --format=sysv %t.64-bit.o 2>&1 | FileCheck -DSIZE=49 -DSYMSIZE=24 %s
+
+## b) Test berkeley output format.
+# RUN: not llvm-size --common --format=berkeley %t.32-bit.o 2>&1 | FileCheck -DSIZE=33 -DSYMSIZE=16 %s
+# RUN: not llvm-size --common --format=berkeley %t.64-bit.o 2>&1 | FileCheck -DSIZE=49 -DSYMSIZE=24 %s
+
+# CHECK: error: {{.*}} section [index 1] has an invalid sh_size ([[SIZE]]) which is not a multiple of its sh_entsize ([[SYMSIZE]])
+
+--- !ELF
+FileHeader:
+  Class:   ELFCLASS[[BITS]]
+  Data:    ELFDATA2LSB
+  Type:    ET_DYN
+  Machine: EM_X86_64
+Sections:
+  - Name:    .symtab
+    Type:    SHT_SYMTAB
+    Size:    [[SIZE]]

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

if (!SegSect.empty() && MachO) {
     // If this section is not in the object file no symbols are printed.
     if (Nsect == 0)
       return;
   }
   if (!(MachO && DyldInfoOnly)) {
     for (BasicSymbolRef Sym : Symbols) {
       Expected<uint32_t> SymFlagsOrErr = Sym.getFlags();
       if (!SymFlagsOrErr) {
-        // TODO: Test this error.
         error(SymFlagsOrErr.takeError(), Obj.getFileName());
         return;
       }
       if (!DebugSyms && (*SymFlagsOrErr & SymbolRef::SF_FormatSpecific))
         continue;
       if (WithoutAliases && (*SymFlagsOrErr & SymbolRef::SF_Indirect))
         continue;
       // If a "-s segname sectname" option was specified and this is a Mach-O

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

 
 /// Total size of all ELF common symbols
 static Expected<uint64_t> getCommonSize(ObjectFile *Obj) {
   uint64_t TotalCommons = 0;
   for (auto &Sym : Obj->symbols()) {
     Expected<uint32_t> SymFlagsOrErr =
         Obj->getSymbolFlags(Sym.getRawDataRefImpl());
     if (!SymFlagsOrErr)
-      // TODO: Test this error.
       return SymFlagsOrErr.takeError();
     if (*SymFlagsOrErr & SymbolRef::SF_Common)
       TotalCommons += Obj->getCommonSymbolSize(Sym.getRawDataRefImpl());
   }
   return TotalCommons;
 }
 
 /// Print the size of each Mach-O segment and section in @p MachO.