[cfi] Help sanstats to find binary if they are not at the original location

Summary:
By default sanstats search binaries at the same location where they were when
stats was collected. Sometime you can not print report immediately or you need
to move post-processing to another workstation. To support this use-case when
original binary is missing sanstats will fall-back to directory with sanstats
file.

Reviewers: pcc

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D53857

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@347601 91177308-0d34-0410-b5e6-96231b3b80d8

test/tools/sanstats/elf.test

@@ -25,6 +25,16 @@
 
 # RUN: sanstats %t.stats | FileCheck %s
 
+# Test that if binaries are not in the original location then sanstats
+# searches them next to the stats file.
+# RUN: mkdir -p %t.dir
+# RUN: mv -f %t1.o %t2.o %t.dir
+# RUN: sanstats %t.stats | FileCheck %s --check-prefix=INVALID
+# RUN: mv -f %t.stats %t.dir/copy.stats
+# RUN: cd %t.dir && sanstats copy.stats | FileCheck %s
+
+# INVALID: <invalid>
+# CHECK-NOT: <invalid>
 # CHECK: 0x0000000000000000 /tmp{{[/\\]}}f.c:1 f1 cfi-vcall 1
 # CHECK: 0x0000000000000010 /tmp{{[/\\]}}f.c:2 f2 cfi-nvcall 2
 # CHECK: 0x0000000000000020 /tmp{{[/\\]}}f.c:3 f3 cfi-derived-cast 3

tools/sanstats/sanstats.cpp

@@ -15,7 +15,9 @@
 #include "llvm/DebugInfo/Symbolize/Symbolize.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/ErrorOr.h"
+#include "llvm/Support/FileSystem.h"
 #include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/Path.h"
 #include "llvm/Transforms/Utils/SanitizerStats.h"
 #include <stdint.h>
 
@@ -52,7 +54,11 @@ const char *ReadModule(char SizeofPtr, const char *Begin, const char *End) {
     ++Begin;
   if (Begin == End)
     return nullptr;
-  StringRef Filename(FilenameBegin, Begin - FilenameBegin);
+  std::string Filename(FilenameBegin, Begin - FilenameBegin);
+
+  if (!llvm::sys::fs::exists(Filename))
+    Filename = std::string(llvm::sys::path::parent_path(ClInputFile)) +
+               std::string(llvm::sys::path::filename(Filename));
 
   ++Begin;
   if (Begin == End)