[llvm-commits] [PATCH] [asan] Always use file+offset in symbolizer

[NAKAMURA Takumi]

compiler-rt/asan: MemoryMappingLayout: Always emit the offset in corresponding module.

asan_symbolize.py: Use offset with (rounded to page_size) base address, with objdump(1).

FIXME: I have not tested on darwin.

http://llvm-reviews.chandlerc.com/D66

Files:
  compiler-rt/lib/asan/scripts/asan_symbolize.py
  compiler-rt/lib/sanitizer_common/sanitizer_procmaps.h

Index: compiler-rt/lib/asan/scripts/asan_symbolize.py
===================================================================
--- compiler-rt/lib/asan/scripts/asan_symbolize.py
+++ compiler-rt/lib/asan/scripts/asan_symbolize.py
@@ -109,6 +109,28 @@
     super(Addr2LineSymbolizer, self).__init__()
     self.binary = binary
     self.pipe = self.open_addr2line()
+    self.base = self.get_base_addr()
+
+  def get_base_addr(self):
+    p = subprocess.Popen(
+      ['objdump', '-h', self.binary],
+      stdin=None,
+      stdout=subprocess.PIPE
+      )
+    # Capture the first VMA with 'LOAD'.
+    a = re.compile(r'\s+(?P<Size>[0-9a-f]{8,})\s+(?P<VMA>[0-9a-f]{8,})\s+(?P<LMA>[0-9a-f]{8,})\s+(?P<offset>[0-9a-f]{8,})\s+')
+    b = re.compile(r'\WLOAD\W')
+    base = '';
+    vma = ''
+    for line in p.stdout:
+      ma = a.search(line)
+      if ma:
+        vma = ma.group('VMA')
+      elif base == '' and vma != '' and b.search(line):
+        base = vma
+
+    p.wait()
+    return int(base, 16) & -4096
 
   def open_addr2line(self):
     cmd = ['addr2line', '-f', '-e', self.binary]
@@ -122,6 +144,7 @@
     if self.binary != binary:
       return None
     try:
+      offset = "0x%x" % (self.base + int(offset, 16))
       print >> self.pipe.stdin, offset
       function_name = self.pipe.stdout.readline().rstrip()
       file_name = self.pipe.stdout.readline().rstrip()
Index: compiler-rt/lib/sanitizer_common/sanitizer_procmaps.h
===================================================================
--- compiler-rt/lib/sanitizer_common/sanitizer_procmaps.h
+++ compiler-rt/lib/sanitizer_common/sanitizer_procmaps.h
@@ -52,18 +52,8 @@
     for (int i = 0; Next(&start, &end, &file_offset, filename, filename_size);
          i++) {
       if (addr >= start && addr < end) {
-        // Don't subtract 'start' for the first entry:
-        // * If a binary is compiled w/o -pie, then the first entry in
-        //   process maps is likely the binary itself (all dynamic libs
-        //   are mapped higher in address space). For such a binary,
-        //   instruction offset in binary coincides with the actual
-        //   instruction address in virtual memory (as code section
-        //   is mapped to a fixed memory range).
-        // * If a binary is compiled with -pie, all the modules are
-        //   mapped high at address space (in particular, higher than
-        //   shadow memory of the tool), so the module can't be the
-        //   first entry.
-        *offset = (addr - (i ? start : 0)) + file_offset;
+	// FIXME: file_offset doesn't make sense if it is not zero.
+        *offset = (addr - start) + file_offset;
         return true;
       }
     }
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