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

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

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);
+}