[llvm-symbolizer] Improve compatibility of llvm-symbolizer --functions with GNU addr2line

[jhenderson]

Summary

This fixes https://bugs.llvm.org/show_bug.cgi?id=40072.

GNU addr2line's --functions switch is off by default, has a short alias of -f, and does not take an argument. This patch changes llvm-symbolizer to allow the second and third point (changing the default behaviour may have negative impacts on users). If the option is missing a value, it now treats it as "linkage".

This change does cause one previously valid command-line to behave differently. Before --functions <value> was accepted, but now only --functions=<value> is allowed (as well as --functions). The old behaviour will result in the value being treated as a positional argument.

The previous testing for --functions=short has been pulled out into a new test that also tests the other accepted values and option formats.

[jhenderson]

Add cl::Grouping to short alias (see also https://bugs.llvm.org/show_bug.cgi?id=40304 and D57046).

[ruiu]

test/tools/llvm-symbolizer/functions.test

3

Can't tests for llvm-symbolizer depend on llvm-mc? If it can, can you represent functions.o in assembly and assemble it at test-time so that you can avoid checking in a binary file?

[jhenderson]

test/tools/llvm-symbolizer/functions.test

3

I tried that first using llvm-mc -g but that produces ?? for the function name of --functions=short. I could be persuaded that that's fine, because it shows a difference in behaviour between them, but it doesn't really test short function names.

Another alternative would be to create manually-written .debug* data. I'll have a look and see if that's practical, but I think that would make the test somewhat harder to read.

[jhenderson]

Use llvm-mc and assembly as test input instead of a pre-built object.

[ruiu]

LGTM

docs/CommandGuide/llvm-symbolizer.rst

 
 OPTIONS
 -------
 
 .. option:: -obj, -exe, -e
 
   Path to object file to be symbolized.
 
-.. option:: -functions=[none|short|linkage]
+.. option:: -functions[=<none|short|linkage>], -f
 
   Specify the way function names are printed (omit function name,
   print short function name, or print full linkage name, respectively).
   Defaults to ``linkage``.
 
 .. option:: -use-symbol-table
 
  Prefer function names stored in symbol table to function names

test/DebugInfo/llvm-symbolizer.test

 BINARY_C:      {{g$}}
 
 RUN: echo "0x1f1" > %t.input6
 RUN: llvm-symbolizer --obj %p/Inputs/shared-object-stripped.elf-i386 < %t.input6 \
 RUN:   | FileCheck %s --check-prefix=STRIPPED
 
 STRIPPED:  global_func
 
-RUN: echo "%p/Inputs/dwarfdump-test4.elf-x86-64 0x62c" > %t.input7
-RUN: llvm-symbolizer --functions=short --demangle=false < %t.input7 \
-RUN:    | FileCheck %s --check-prefix=SHORT_FUNCTION_NAME
-RUN: llvm-symbolizer --functions=short -C=false < %t.input7 \
-RUN:    | FileCheck %s --check-prefix=SHORT_FUNCTION_NAME
-
-SHORT_FUNCTION_NAME-NOT: _Z1cv
-
 ; Check that the last of --demangle and --no-demangle wins.
+RUN: echo "%p/Inputs/dwarfdump-test4.elf-x86-64 0x62c" > %t.input7
 RUN: llvm-symbolizer --demangle < %t.input7 \
 RUN:    | FileCheck %s --check-prefix=DEMANGLED_FUNCTION_NAME
+RUN: llvm-symbolizer -C < %t.input7 \
+RUN:    | FileCheck %s --check-prefix=DEMANGLED_FUNCTION_NAME
 RUN: llvm-symbolizer --no-demangle < %t.input7 \
 RUN:    | FileCheck %s --check-prefix=MANGLED_FUNCTION_NAME
 RUN: llvm-symbolizer --demangle --no-demangle < %t.input7 \
 RUN:    | FileCheck %s --check-prefix=MANGLED_FUNCTION_NAME
+RUN: llvm-symbolizer -C --no-demangle < %t.input7 \
+RUN:    | FileCheck %s --check-prefix=MANGLED_FUNCTION_NAME
 RUN: llvm-symbolizer --no-demangle --demangle < %t.input7 \
 RUN:    | FileCheck %s --check-prefix=DEMANGLED_FUNCTION_NAME
+RUN: llvm-symbolizer --no-demangle -C < %t.input7 \
+RUN:    | FileCheck %s --check-prefix=DEMANGLED_FUNCTION_NAME
 
 MANGLED_FUNCTION_NAME: _Z1cv
 DEMANGLED_FUNCTION_NAME: c()

test/tools/llvm-symbolizer/Inputs/functions.cpp

+// Build using clang -target x86_64-pc-linux -c -g
+void foo(int bar) {}

test/tools/llvm-symbolizer/functions.test

+# REQUIRES: x86-registered-target
+
+# RUN: llvm-symbolizer 0 --obj=%p/Inputs/functions.o | FileCheck %s --check-prefix=LINKAGE
+# RUN: llvm-symbolizer 0 --functions --obj=%p/Inputs/functions.o | FileCheck %s --check-prefix=LINKAGE
+# RUN: llvm-symbolizer 0 --functions=linkage --obj=%p/Inputs/functions.o | FileCheck %s --check-prefix=LINKAGE
+# RUN: llvm-symbolizer 0 --functions=short --obj=%p/Inputs/functions.o | FileCheck %s --check-prefix=SHORT
+# RUN: llvm-symbolizer 0 --functions=none --obj=%p/Inputs/functions.o | FileCheck %s --check-prefix=NONE
+
+## Characterise behaviour for no '=' sign. llvm-symbolizer treats the next option as an
+## input address, and just prints it.
+# RUN: llvm-symbolizer 0 --functions none --obj=%p/Inputs/functions.o | FileCheck %s --check-prefixes=LINKAGE,ERR
+
+# LINKAGE:      {{^}}foo(int){{$}}
+# LINKAGE-NEXT: functions.cpp:2:0
+
+# SHORT:      {{^}}foo{{$}}
+# SHORT-NEXT: functions.cpp:2:0
+
+# NONE-NOT: foo
+# NONE:     functions.cpp:2:0
+
+# ERR: none

tools/llvm-symbolizer/llvm-symbolizer.cpp

 
 static cl::opt<bool>
 ClUseSymbolTable("use-symbol-table", cl::init(true),
                  cl::desc("Prefer names in symbol table to names "
                           "in debug info"));
 
 static cl::opt<FunctionNameKind> ClPrintFunctions(
     "functions", cl::init(FunctionNameKind::LinkageName),
-    cl::desc("Print function name for a given address:"),
+    cl::desc("Print function name for a given address:"), cl::ValueOptional,
     cl::values(clEnumValN(FunctionNameKind::None, "none", "omit function name"),
                clEnumValN(FunctionNameKind::ShortName, "short",
                           "print short function name"),
                clEnumValN(FunctionNameKind::LinkageName, "linkage",
-                          "print function linkage name")));
+                          "print function linkage name (default)"),
+               // Sentinel value for unspecified value.
+               clEnumValN(FunctionNameKind::LinkageName, "", "")));
+static cl::alias ClPrintFunctionsShort("f", cl::desc("Alias for -functions"),
+                                       cl::NotHidden, cl::Grouping,
+                                       cl::aliasopt(ClPrintFunctions));
 
 static cl::opt<bool>
     ClUseRelativeAddress("relative-address", cl::init(false),
                          cl::desc("Interpret addresses as relative addresses"),
                          cl::ReallyHidden);
 
 static cl::opt<bool>
     ClPrintInlining("inlining", cl::init(true),