analyzer: do not segfault when printing unknown impl location

When dump_impl_location_t::m_function or dump_impl_location_t::m_file is NULL,
then GCC segfaults when attempting to print the location.

$ ./bin/arm-none-eabi-gcc ../ice-pr124055-1.c -fanalyzer -Wanalyzer-too-complex -Wanalyzer-symbol-too-complex -O -fdump-analyzer -frounding-math -S -o /dev/null -wrapper lldb,--
(lldb) target create "/build/r16-8473-g5cc0ead3625fe6/bin/../lib/gcc/arm-none-eabi/16.0.1/cc1"
...
(lldb) r
Process 31748 launched: '/build/r16-8473-g5cc0ead3625fe6/lib/gcc/arm-none-eabi/16.0.1/cc1' (arm64)
Process 31748 stopped
* thread #1, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0x0)
    frame #0: 0x000000018ae7ea44 libsystem_platform.dylib`_platform_strlen + 4
libsystem_platform.dylib`_platform_strlen:
->  0x18ae7ea44 <+4>:  ldr    q0, [x1]
    0x18ae7ea48 <+8>:  adr    x3, 0x18ae7e980 ; ___lldb_unnamed_symbol320
    0x18ae7ea4c <+12>: ldr    q2, [x3], #0x10
    0x18ae7ea50 <+16>: and    x2, x0, #0xf
Target 0: (cc1) stopped.
(lldb) bt
* thread #1, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0x0)
  * frame #0: 0x000000018ae7ea44 libsystem_platform.dylib`_platform_strlen + 4
    frame #1: 0x0000000101223d68 cc1`pp_quoted_string(pretty_printer*, char const*, unsigned long) + 244
    frame #2: 0x0000000101220628 cc1`pretty_printer::format(text_info&) + 2772
    frame #3: 0x0000000101108b8c cc1`ana::logger::log_va(char const*, char**) + 100
    frame #4: 0x0000000101108970 cc1`ana::logger::log(char const*, ...) + 28
    frame #5: 0x0000000101129da4 cc1`ana::impl_region_model_context::on_unexpected_tree_code(tree_node*, dump_location_t const&) + 80
    frame #6: 0x0000000101174d3c cc1`ana::region_model_manager::get_region_for_unexpected_tree_code(ana::region_model_context*, tree_node*, dump_location_t const&) + 184
...

This happens when GCC is built with GCC <4.8 or with another toolchain,
like LLVM. Seen on macOS with clang-1600.0.26.6.

gcc/analyzer/ChangeLog:

	* engine.cc (impl_region_model_context::on_unexpected_tree_code): Print
	"<unknown>" when m_file or m_function is NULL.

Signed-off-by: Torbjörn SVENSSON <torbjorn.svensson@foss.st.com>

diff --git a/gcc/analyzer/engine.cc b/gcc/analyzer/engine.cc
index a4d870bd3d242ad49c6e6244e8384b8cb2cd3f9c..a5ab173ca16bafff01e5a620e75d9e60bb93a147 100644 (file)
--- a/gcc/analyzer/engine.cc
+++ b/gcc/analyzer/engine.cc
@@ -904,11 +904,15 @@ impl_region_model_context::on_unexpected_tree_code (tree t,
 {
   logger * const logger = get_logger ();
   if (logger)
-    logger->log ("unhandled tree code: %qs in %qs at %s:%i",
-                get_tree_code_name (TREE_CODE (t)),
-                loc.get_impl_location ().m_function,
-                loc.get_impl_location ().m_file,
-                loc.get_impl_location ().m_line);
+    {
+      const dump_impl_location_t &impl_loc = loc.get_impl_location ();
+      const char *unknown = "<unknown>";
+      logger->log ("unhandled tree code: %qs in %qs at %s:%i",
+                  get_tree_code_name (TREE_CODE (t)),
+                  impl_loc.m_function ? impl_loc.m_function : unknown,
+                  impl_loc.m_file ? impl_loc.m_file : unknown,
+                  impl_loc.m_line);
+    }
   if (m_new_state)
     m_new_state->m_valid = false;
 }