New symbolizer option to print files relative to the compilation directory.

Summary: New "--relative" option to allow printing files relative to the compilation directory.

Reviewers: jhenderson

Subscribers: MaskRay, rupprecht, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D76733

Author: Sterling-Augustine

llvm/docs/CommandGuide/llvm-symbolizer.rst

@@ -147,6 +147,27 @@ Example 4 - CODE and DATA prefixes:
   bar
   6295592 4
 
+Example 5 - path-style options:
+
+This example uses the same source file as above, but the source file's
+full path is /tmp/foo/test.cpp and is compiled as follows. The first case
+shows the default absolute path, the second --basenames, and the third
+shows --relativenames.
+
+.. code-block:: console
+  $ pwd
+  /tmp
+  $ clang -g foo/test.cpp -o test.elf
+  $ llvm-symbolizer --obj=test.elf 0x4004a0 
+  main
+  /tmp/foo/test.cpp:15:0
+  $ llvm-symbolizer --obj=test.elf 0x4004a0 --basenames
+  main
+  test.cpp:15:0
+  $ llvm-symbolizer --obj=test.elf 0x4004a0 --relativenames
+  main
+  foo/test.cpp:15:0
+   
 OPTIONS
 -------
 
@@ -158,8 +179,15 @@ OPTIONS
 
 .. option:: --basenames, -s
 
-  Strip directories when printing the file path.
+  Print just the file's name without any directories, instead of the
+  absolute path.
 
+.. option:: --relativenames
+
+  Print the file's path relative to the compilation directory, instead
+  of the absolute path. If the command-line to the compiler included
+  the full path, this will be the same as the default.
+  
 .. _llvm-symbolizer-opt-C:
 
 .. option:: --demangle, -C

llvm/test/tools/llvm-symbolizer/relativenames.s

@@ -0,0 +1,18 @@
+# REQUIRES: x86-registered-target
+
+foo:
+    nop
+
+# RUN: llvm-mc --filetype=obj --triple=x86_64-pc-linux %s -o %t.o -g
+
+# RUN: llvm-symbolizer 0 --relativenames --obj=%t.o \
+# RUN:    | FileCheck %s -DDIR=%p --check-prefix=RELATIVENAMES
+
+## Ensure last option wins.
+# RUN: llvm-symbolizer 0 --basenames --relativenames --obj=%t.o \
+# RUN:    | FileCheck %s -DDIR=%p --check-prefix=RELATIVENAMES
+# RUN: llvm-symbolizer 0 --relativenames --basenames --obj=%t.o \
+# RUN:    | FileCheck %s --check-prefix=BASENAMES
+
+# RELATIVENAMES: [[DIR]]{{\\|/}}relativenames.s:4
+# BASENAMES: {{^}}relativenames.s:4

llvm/tools/llvm-symbolizer/llvm-symbolizer.cpp

@@ -77,6 +77,11 @@ static cl::opt<bool> ClBasenames("basenames", cl::init(false),
 static cl::alias ClBasenamesShort("s", cl::desc("Alias for -basenames"),
                                   cl::NotHidden, cl::aliasopt(ClBasenames));
 
+// -relativenames
+static cl::opt<bool>
+    ClRelativenames("relativenames", cl::init(false),
+                    cl::desc("Strip the compilation directory from paths"));
+
 // -demangle, -C, -no-demangle
 static cl::opt<bool>
 ClDemangle("demangle", cl::init(true), cl::desc("Demangle function names"));
@@ -310,8 +315,12 @@ int main(int argc, char **argv) {
   Opts.DWPName = ClDwpName;
   Opts.DebugFileDirectory = ClDebugFileDirectory;
   Opts.PathStyle = DILineInfoSpecifier::FileLineInfoKind::AbsoluteFilePath;
-  if (ClBasenames)
+  // If both --basenames and --relativenames are specified then pick the last
+  // one.
+  if (ClBasenames.getPosition() > ClRelativenames.getPosition())
     Opts.PathStyle = DILineInfoSpecifier::FileLineInfoKind::BaseNameOnly;
+  else if (ClRelativenames)
+    Opts.PathStyle = DILineInfoSpecifier::FileLineInfoKind::RelativeFilePath;
 
   for (const auto &hint : ClDsymHint) {
     if (sys::path::extension(hint) == ".dSYM") {