Do not call null register_common in emutls

Thread-local variables with DECL_COMMON trigger an internal compiler
error on targets that use emulated TLS without register_common, when
we attempt to expand a call to the NULL register_common, with
testcases as simple as gcc.dg/tls/emutls-2.c.

The documentation states that, on such targets, common variables would
fall back to explicitly initialized.  This patch rearranges the code
that deals with initialization of common and non-common variables,
complementing code that is already in place to detect
register_common-less targets.


for  gcc/ChangeLog

	* tree-emutls.c (new_emutls_decl, emutls_common_1): Complete
	handling of register_common-less targets.

for  gcc/testsuite/ChangeLog

	* gcc.dg/tls/emutls-3.c: New, combining emutls-2.c and
	thr-init-2.c into an execution test with explicitly common
	variables.
This commit is contained in:
Alexandre Oliva 2020-02-17 17:08:11 -03:00 committed by Alexandre Oliva
parent bc0f8df124
commit 96bae436e0
4 changed files with 39 additions and 2 deletions

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@ -1,3 +1,8 @@
2020-02-17 Alexandre Oliva <oliva@adacore.com>
* tree-emutls.c (new_emutls_decl, emutls_common_1): Complete
handling of register_common-less targets.
2020-02-17 Martin Liska <mliska@suse.cz>
PR ipa/93760

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@ -1,3 +1,9 @@
2020-02-17 Alexandre Oliva <oliva@adacore.com>
* gcc.dg/tls/emutls-3.c: New, combining emutls-2.c and
thr-init-2.c into an execution test with explicitly common
variables.
2020-02-17 Wilco Dijkstra <wdijkstr@arm.com>
* gcc.target/aarch64/pr93565.c: Fix test for ilp32.

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@ -0,0 +1,26 @@
/* { dg-do run } */
/* { dg-require-effective-target tls } */
/* { dg-require-effective-target global_constructor } */
/* { dg-options "-O2" } */
/* { dg-require-effective-target tls_runtime } */
/* { dg-add-options tls } */
__thread int i __attribute__((common));
extern void abort (void);
int test_code(int b)
{
i += b ;
return i;
}
int main (int ac, char *av[])
{
int a = test_code(test_code(1));
if ((a != 2) || (i != 2))
abort () ;
return 0;
}

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@ -322,7 +322,7 @@ new_emutls_decl (tree decl, tree alias_of)
control structure with size and alignment information. Initialization
of COMMON block variables happens elsewhere via a constructor. */
if (!DECL_EXTERNAL (to)
&& (!DECL_COMMON (to)
&& (!DECL_COMMON (to) || !targetm.emutls.register_common
|| (DECL_INITIAL (decl)
&& DECL_INITIAL (decl) != error_mark_node)))
{
@ -360,7 +360,7 @@ emutls_common_1 (tree tls_decl, tree control_decl, tree *pstmts)
tree x;
tree word_type_node;
if (! DECL_COMMON (tls_decl)
if (!DECL_COMMON (tls_decl) || !targetm.emutls.register_common
|| (DECL_INITIAL (tls_decl)
&& DECL_INITIAL (tls_decl) != error_mark_node))
return;