diff options
author | David Malcolm <dmalcolm@redhat.com> | 2020-03-30 11:13:59 -0400 |
---|---|---|
committer | David Malcolm <dmalcolm@redhat.com> | 2020-03-30 21:03:00 -0400 |
commit | 3809bcd6c0ee324cbd855c68cee104c8bf134dbe (patch) | |
tree | 568baf4fc6b07c0092c61cdfad2ad9ba176156ac /gcc/lra.c | |
parent | 13a29fc5730ac3a5e3296971d15ca63dcc0ae261 (diff) |
lra: set insn_code_data to NULL when freeing
libgccjit's test-threads.c repeatedly compiles and runs numerous tests,
each in a separate thread.
Attempting to add an empty test that generates no code leads to a
double-free ICE within that thread, within lra.c's
finish_insn_code_data_once.
The root cause is that the insn_code_data array is cleared in
init_insn_code_data_once, but this is only called the first time
a cgraph_node is expanded [1], whereas the "loop-over-all-elements
and free them" is unconditionally called in finalize [2]. Hence
if there are no functions:
* the array is not re-initialized for the empty context
* when finish_insn_code_data_once is called for the empty context
it still contains the freed pointers from the previous context
that held the jit mutex, and hence the free is a double-free.
This patch sets the pointers to NULL after freeing them, fixing
the ICE.
[1]
init_insn_code_data_once is called via
lra_init_once called by
ira_init_once called by
initialize_rtl, via:
if (!rtl_initialized)
ira_init_once ();
called by init_function_start
called by cgraph_node::expand
[2]:
finish_insn_code_data_once is called by:
lra_finish_once called by
finalize
gcc/ChangeLog:
* lra.c (finish_insn_code_data_once): Set the array elements
to NULL after freeing them.
gcc/testsuite/ChangeLog:
* jit.dg/all-non-failing-tests.h: Add test-empty.c
Diffstat (limited to 'gcc/lra.c')
-rw-r--r-- | gcc/lra.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/gcc/lra.c b/gcc/lra.c index d5ea3622686..5e8b75b1fda 100644 --- a/gcc/lra.c +++ b/gcc/lra.c @@ -653,7 +653,10 @@ finish_insn_code_data_once (void) for (unsigned int i = 0; i < NUM_INSN_CODES; i++) { if (insn_code_data[i] != NULL) - free (insn_code_data[i]); + { + free (insn_code_data[i]); + insn_code_data[i] = NULL; + } } } |