Re: [PATCH][gcc] libgccjit: handle long literals in playback::context::new_string_literal

[Andrea Corallo <Andrea dot Corallo at arm dot com>]

Andrea Corallo writes:

> Andrea Corallo writes:
>
>> Andrea Corallo writes:
>>
>>> Hi all,
>>> yesterday I've found an interesting bug in libgccjit.
>>> Seems we have an hard limitation of 200 characters for literal strings.
>>> Attempting to create longer strings lead to ICE during pass_expand
>>> while performing a sanity check in get_constant_size.
>>>
>>> Tracking down the issue seems the code we have was inspired from
>>> c-family/c-common.c:c_common_nodes_and_builtins were array_domain_type
>>> is actually defined with a size of 200.
>>> The comment that follows that point sounded premonitory :) :)
>>>
>>> /* Make a type for arrays of characters.
>>>    With luck nothing will ever really depend on the length of this
>>>    array type.  */
>>>
>>> At least in the current implementation the type is set by
>>> fix_string_type were the actual string length is taken in account.
>>>
>>> I attach a patch updating the logic accordingly and a new testcase
>>>  for that.
>>>
>>> make check-jit is passing clean.
>>>
>>> Best Regards
>>>   Andrea
>>>
>>> gcc/jit/ChangeLog
>>> 2019-??-??  Andrea Corallo  <andrea.corallo@arm.com>
>>>
>>> 	* jit-playback.h
>>> 	(gcc::jit::recording::context m_recording_ctxt): Remove
>>> 	m_char_array_type_node field.
>>> 	* jit-playback.c
>>> 	(playback::context::context) Remove m_char_array_type_node from member
>>> 	initializer list.
>>> 	(playback::context::new_string_literal) Fix logic to handle string
>>> 	length > 200.
>>>
>>> gcc/testsuite/ChangeLog
>>> 2019-??-??  Andrea Corallo  <andrea.corallo@arm.com>
>>>
>>> 	* jit.dg/all-non-failing-tests.h: Add test-long-string-literal.c.
>>> 	* jit.dg/test-long-string-literal.c: New testcase.
>>> diff --git a/gcc/jit/jit-playback.c b/gcc/jit/jit-playback.c
>>> index 9eeb2a7..a26b8d3 100644
>>> --- a/gcc/jit/jit-playback.c
>>> +++ b/gcc/jit/jit-playback.c
>>> @@ -88,7 +88,6 @@ playback::context::context (recording::context *ctxt)
>>>    : log_user (ctxt->get_logger ()),
>>>      m_recording_ctxt (ctxt),
>>>      m_tempdir (NULL),
>>> -    m_char_array_type_node (NULL),
>>>      m_const_char_ptr (NULL)
>>>  {
>>>    JIT_LOG_SCOPE (get_logger ());
>>> @@ -670,9 +669,12 @@ playback::rvalue *
>>>  playback::context::
>>>  new_string_literal (const char *value)
>>>  {
>>> -  tree t_str = build_string (strlen (value), value);
>>> -  gcc_assert (m_char_array_type_node);
>>> -  TREE_TYPE (t_str) = m_char_array_type_node;
>>> +  /* Compare with c-family/c-common.c: fix_string_type.  */
>>> +  size_t len = strlen (value);
>>> +  tree i_type = build_index_type (size_int (len));
>>> +  tree a_type = build_array_type (char_type_node, i_type);
>>> +  tree t_str = build_string (len, value);
>>> +  TREE_TYPE (t_str) = a_type;
>>>
>>>    /* Convert to (const char*), loosely based on
>>>       c/c-typeck.c: array_to_pointer_conversion,
>>> @@ -2703,10 +2705,6 @@ playback::context::
>>>  replay ()
>>>  {
>>>    JIT_LOG_SCOPE (get_logger ());
>>> -  /* Adapted from c-common.c:c_common_nodes_and_builtins.  */
>>> -  tree array_domain_type = build_index_type (size_int (200));
>>> -  m_char_array_type_node
>>> -    = build_array_type (char_type_node, array_domain_type);
>>>
>>>    m_const_char_ptr
>>>      = build_pointer_type (build_qualified_type (char_type_node,
>>> diff --git a/gcc/jit/jit-playback.h b/gcc/jit/jit-playback.h
>>> index d4b148e..801f610 100644
>>> --- a/gcc/jit/jit-playback.h
>>> +++ b/gcc/jit/jit-playback.h
>>> @@ -322,7 +322,6 @@ private:
>>>
>>>    auto_vec<function *> m_functions;
>>>    auto_vec<tree> m_globals;
>>> -  tree m_char_array_type_node;
>>>    tree m_const_char_ptr;
>>>
>>>    /* Source location handling.  */
>>> diff --git a/gcc/testsuite/jit.dg/all-non-failing-tests.h b/gcc/testsuite/jit.dg/all-non-failing-tests.h
>>> index 0272e6f8..1b3d561 100644
>>> --- a/gcc/testsuite/jit.dg/all-non-failing-tests.h
>>> +++ b/gcc/testsuite/jit.dg/all-non-failing-tests.h
>>> @@ -220,6 +220,13 @@
>>>  #undef create_code
>>>  #undef verify_code
>>>
>>> +/* test-long-string-literal.c */
>>> +#define create_code create_code_long_string_literal
>>> +#define verify_code verify_code_long_string_literal
>>> +#include "test-long-string-literal.c"
>>> +#undef create_code
>>> +#undef verify_code
>>> +
>>>  /* test-sum-of-squares.c */
>>>  #define create_code create_code_sum_of_squares
>>>  #define verify_code verify_code_sum_of_squares
>>> diff --git a/gcc/testsuite/jit.dg/test-long-string-literal.c b/gcc/testsuite/jit.dg/test-long-string-literal.c
>>> new file mode 100644
>>> index 0000000..882567c
>>> --- /dev/null
>>> +++ b/gcc/testsuite/jit.dg/test-long-string-literal.c
>>> @@ -0,0 +1,48 @@
>>> +#include <stdlib.h>
>>> +#include <stdio.h>
>>> +#include <string.h>
>>> +
>>> +#include "libgccjit.h"
>>> +
>>> +#include "harness.h"
>>> +
>>> +const char very_long_string[] =
>>> +  "abcabcabcabcabcabcabcabcabcabcabcabcabcabcabcabcabcabcabcabcabcabcabcabcabc"
>>> +  "abcabcabcabcabcabcabcabcabcabcabcabcabcabcabcabcabcabcabcabcabcabcabcabcabc"
>>> +  "abcabcabcabcabcabcabcabcabcabcabcabcabcabcabcabcabcabcabcabcabcabcabcabcabc"
>>> +  "abcabcabcabcabcabcabcabcabcabca";
>>> +
>>> +void
>>> +create_code (gcc_jit_context *ctxt, void *user_data)
>>> +{
>>> +  /* Build the test_fn.  */
>>> +  gcc_jit_function *f =
>>> +    gcc_jit_context_new_function (
>>> +      ctxt, NULL,
>>> +      GCC_JIT_FUNCTION_EXPORTED,
>>> +      gcc_jit_context_get_type(ctxt,
>>> +			       GCC_JIT_TYPE_CONST_CHAR_PTR),
>>> +				"test_long_string_literal",
>>> +				0, NULL, 0);
>>> +  gcc_jit_block *blk =
>>> +    gcc_jit_function_new_block (f, "init_block");
>>> +  gcc_jit_rvalue *res =
>>> +    gcc_jit_context_new_string_literal (ctxt, very_long_string);
>>> +
>>> +  gcc_jit_block_end_with_return (blk, NULL, res);
>>> +}
>>> +
>>> +void
>>> +verify_code (gcc_jit_context *ctxt, gcc_jit_result *result)
>>> +{
>>> +  typedef const char *(*fn_type) (void);
>>> +  CHECK_NON_NULL (result);
>>> +  fn_type test_long_string_literal =
>>> +    (fn_type)gcc_jit_result_get_code (result, "test_long_string_literal");
>>> +  CHECK_NON_NULL (test_long_string_literal);
>>> +
>>> +  /* Call the JIT-generated function.  */
>>> +  const char *str = test_long_string_literal ();
>>> +  CHECK_NON_NULL (str);
>>> +  CHECK_VALUE (strcmp (str, very_long_string), 0);
>>> +}
>>
>> Kindly pinging
>>
>> Bests
>>   Andrea
>
> Hi,
> I'd like to ping this patch.
>
> Bests
>  Andrea

Pinging again.

Bests
  Andrea