On Wed, Nov 17, 2021 at 7:25 AM apinski--- via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> From: Andrew Pinski <apin...@marvell.com>
>
> The Linux kernel started to fail compile when the jump threader was improved
> (r12-2591-g2e96b5f14e4025691). This failure was due to the IPA splitting code
> decided now to split off the basic block which contained two functions,
> one of those functions included the error attribute on them. This patch fixes
> the problem by disallowing basic blocks from being split which contain
> functions
> that have either the error or warning attribute on them.
>
> The two new testcases are to make sure we still split the function for other
> places if we reject the one case.
Hmm, it's only problematic if the immediate(?) controlling condition of the
error/warning annotated call is not in the split part, no? Interestingly
we for example don't avoid splitting away __builtin_constant_p either.
Richard.
> OK? Bootstrapped and tested on x86_64-linux-gnu with no regressions.
>
> PR tree-optimization/101941
>
> gcc/ChangeLog:
>
> * ipa-split.c (visit_bb): Disallow function calls where
> the function has either error or warning attribute.
>
> gcc/testsuite/ChangeLog:
>
> * gcc.c-torture/compile/pr101941-1.c: New test.
> * gcc.dg/tree-ssa/pr101941-1.c: New test.
> ---
> gcc/ipa-split.c | 12 ++++-
> .../gcc.c-torture/compile/pr101941-1.c | 44 +++++++++++++++++
> gcc/testsuite/gcc.dg/tree-ssa/pr101941-1.c | 48 +++++++++++++++++++
> 3 files changed, 103 insertions(+), 1 deletion(-)
> create mode 100644 gcc/testsuite/gcc.c-torture/compile/pr101941-1.c
> create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/pr101941-1.c
>
> diff --git a/gcc/ipa-split.c b/gcc/ipa-split.c
> index c68577d04a9..070e894ef31 100644
> --- a/gcc/ipa-split.c
> +++ b/gcc/ipa-split.c
> @@ -873,7 +873,7 @@ visit_bb (basic_block bb, basic_block return_bb,
> gimple *stmt = gsi_stmt (bsi);
> tree op;
> ssa_op_iter iter;
> - tree decl;
> + tree decl = NULL_TREE;
>
> if (is_gimple_debug (stmt))
> continue;
> @@ -927,6 +927,16 @@ visit_bb (basic_block bb, basic_block return_bb,
> break;
> }
>
> + /* If a function call and that function has either the
> + warning or error attribute on it, don't split. */
> + if (decl && (lookup_attribute ("warning", DECL_ATTRIBUTES (decl))
> + || lookup_attribute ("error", DECL_ATTRIBUTES (decl))))
> + {
> + if (dump_file && (dump_flags & TDF_DETAILS))
> + fprintf (dump_file, "Cannot split: warning or error
> attribute.\n");
> + can_split = false;
> + }
> +
> FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_DEF)
> bitmap_set_bit (set_ssa_names, SSA_NAME_VERSION (op));
> FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_USE)
> diff --git a/gcc/testsuite/gcc.c-torture/compile/pr101941-1.c
> b/gcc/testsuite/gcc.c-torture/compile/pr101941-1.c
> new file mode 100644
> index 00000000000..ab3bbea8ed7
> --- /dev/null
> +++ b/gcc/testsuite/gcc.c-torture/compile/pr101941-1.c
> @@ -0,0 +1,44 @@
> +/* { dg-additional-options "-fconserve-stack" } */
> +struct crypto_aes_ctx {
> + char key_dec[128];
> +};
> +
> +int rfc4106_set_hash_subkey_hash_subkey;
> +
> +void __write_overflow(void)__attribute__((__error__("")));
> +void __write_overflow1(void);
> +void aes_encrypt(void*);
> +
> +void fortify_panic(const char*) __attribute__((__noreturn__)) ;
> +
> +char *rfc4106_set_hash_subkey(struct crypto_aes_ctx *ctx) {
> + void *a = &ctx->key_dec[0];
> + unsigned p_size = __builtin_object_size(a, 0);
> +#ifdef __OPTIMIZE__
> + if (p_size < 16) {
> + __write_overflow1();
> + fortify_panic(__func__);
> + }
> + if (p_size < 32) {
> + __write_overflow();
> + fortify_panic(__func__);
> + }
> +#endif
> + aes_encrypt(ctx);
> + return ctx->key_dec;
> +}
> +
> +char *(*gg)(struct crypto_aes_ctx *) = rfc4106_set_hash_subkey;
> +
> +void a(void)
> +{
> + struct crypto_aes_ctx ctx;
> + rfc4106_set_hash_subkey(&ctx);
> +}
> +void b(void)
> +{
> + struct crypto_aes_ctx ctx;
> + ctx.key_dec[0] = 0;
> + rfc4106_set_hash_subkey(&ctx);
> +}
> +
> diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr101941-1.c
> b/gcc/testsuite/gcc.dg/tree-ssa/pr101941-1.c
> new file mode 100644
> index 00000000000..21c1d1ec466
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/tree-ssa/pr101941-1.c
> @@ -0,0 +1,48 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -fconserve-stack -fdump-tree-optimized" } */
> +struct crypto_aes_ctx {
> + char key_dec[128];
> +};
> +
> +int rfc4106_set_hash_subkey_hash_subkey;
> +
> +void __write_overflow(void)__attribute__((__error__("")));
> +void __write_overflow1(void);
> +void aes_encrypt(void*);
> +
> +void fortify_panic(const char*) __attribute__((__noreturn__)) ;
> +
> +char *rfc4106_set_hash_subkey(struct crypto_aes_ctx *ctx) {
> + void *a = &ctx->key_dec[0];
> + unsigned p_size = __builtin_object_size(a, 0);
> +#ifdef __OPTIMIZE__
> + if (p_size < 16) {
> + __write_overflow1();
> + fortify_panic(__func__);
> + }
> + if (p_size < 32) {
> + __write_overflow();
> + fortify_panic(__func__);
> + }
> +#endif
> + aes_encrypt(ctx);
> + return ctx->key_dec;
> +}
> +
> +char *(*gg)(struct crypto_aes_ctx *) = rfc4106_set_hash_subkey;
> +
> +void a(void)
> +{
> + struct crypto_aes_ctx ctx;
> + rfc4106_set_hash_subkey(&ctx);
> +}
> +void b(void)
> +{
> + struct crypto_aes_ctx ctx;
> + ctx.key_dec[0] = 0;
> + rfc4106_set_hash_subkey(&ctx);
> +}
> +
> +/* This testcase should still split out one of the above basic blocks dealing
> + with __write_overflow. */
> +/* { dg-final { scan-tree-dump-times "Function rfc4106_set_hash_subkey.part"
> 1 "optimized" } } */
> --
> 2.17.1
>
