diff mbox series

S/390: Add support for section anchors

Message ID 20181129124747.9264-1-iii@linux.ibm.com
State New
Headers show
Series S/390: Add support for section anchors | expand

Commit Message

Ilya Leoshkevich Nov. 29, 2018, 12:47 p.m. UTC 
Bootstrapped and regtested on s390x-redhat-linux and
x86_64-redhat-linux.

gcc/ChangeLog:

2018-09-12  Ilya Leoshkevich  <iii@linux.ibm.com>

	* common/config/s390/s390-common.c (s390_option_init_struct):
	Use section anchors by default.
	* config/s390/s390.c (s390_check_symref_alignment): Handle
	anchors.
	(TARGET_MAX_ANCHOR_OFFSET): Use short displacement.
	* output.h (assemble_align): Pass `align' as unsigned int, so
	that the value 0x80000000, which corresponds to `aligned(1 <<
	28)', would pass the `align > BITS_PER_UNIT' check.
	* varasm.c (assemble_align): Likewise.

gcc/testsuite/ChangeLog:

2018-09-12  Ilya Leoshkevich  <iii@linux.ibm.com>

	* gcc.target/s390/nodatarel-1.c: Expect .LANCHOR0@GOTENT instead
	of a@GOTENT.
	* gcc.target/s390/section-anchors.c: New test.
	* gcc.target/s390/section-anchors2.c: New test.
	* gcc.target/s390/section-anchors3.c: New test.
---
 gcc/common/config/s390/s390-common.c          |  3 +++
 gcc/config/s390/s390.c                        | 19 ++++++++++++++
 gcc/output.h                                  |  2 +-
 gcc/testsuite/gcc.target/s390/nodatarel-1.c   |  2 +-
 .../gcc.target/s390/section-anchors.c         | 14 ++++++++++
 .../gcc.target/s390/section-anchors2.c        | 26 +++++++++++++++++++
 .../gcc.target/s390/section-anchors3.c        | 11 ++++++++
 gcc/varasm.c                                  |  2 +-
 8 files changed, 76 insertions(+), 3 deletions(-)
 create mode 100644 gcc/testsuite/gcc.target/s390/section-anchors.c
 create mode 100644 gcc/testsuite/gcc.target/s390/section-anchors2.c
 create mode 100644 gcc/testsuite/gcc.target/s390/section-anchors3.c

Comments

Andreas Krebbel Dec. 3, 2018, 3:04 p.m. UTC | #1 
On 29.11.18 13:47, Ilya Leoshkevich wrote:
> Bootstrapped and regtested on s390x-redhat-linux and
> x86_64-redhat-linux.
> 
> gcc/ChangeLog:
> 
> 2018-09-12  Ilya Leoshkevich  <iii@linux.ibm.com>
> 
> 	* common/config/s390/s390-common.c (s390_option_init_struct):
> 	Use section anchors by default.
> 	* config/s390/s390.c (s390_check_symref_alignment): Handle
> 	anchors.
> 	(TARGET_MAX_ANCHOR_OFFSET): Use short displacement.
> 	* output.h (assemble_align): Pass `align' as unsigned int, so
> 	that the value 0x80000000, which corresponds to `aligned(1 <<
> 	28)', would pass the `align > BITS_PER_UNIT' check.
> 	* varasm.c (assemble_align): Likewise.
> 
> gcc/testsuite/ChangeLog:
> 
> 2018-09-12  Ilya Leoshkevich  <iii@linux.ibm.com>
> 
> 	* gcc.target/s390/nodatarel-1.c: Expect .LANCHOR0@GOTENT instead
> 	of a@GOTENT.
> 	* gcc.target/s390/section-anchors.c: New test.
> 	* gcc.target/s390/section-anchors2.c: New test.
> 	* gcc.target/s390/section-anchors3.c: New test.

Ok. Thanks!

Andreas
diff mbox series

Patch

diff --git a/gcc/common/config/s390/s390-common.c b/gcc/common/config/s390/s390-common.c
index 2f728957e25..59b24654c82 100644
--- a/gcc/common/config/s390/s390-common.c
+++ b/gcc/common/config/s390/s390-common.c
@@ -74,6 +74,9 @@  s390_option_init_struct (struct gcc_options *opts)
   /* By default, always emit DWARF-2 unwind info.  This allows debugging
      without maintaining a stack frame back-chain.  */
   opts->x_flag_asynchronous_unwind_tables = 1;
+
+  /* Enable section anchors by default.  */
+  opts->x_flag_section_anchors = 1;
 }
 
 /* Implement TARGET_HANDLE_OPTION.  */
diff --git a/gcc/config/s390/s390.c b/gcc/config/s390/s390.c
index 277d555440b..62868995ca6 100644
--- a/gcc/config/s390/s390.c
+++ b/gcc/config/s390/s390.c
@@ -4187,6 +4187,20 @@  s390_check_symref_alignment (rtx addr, HOST_WIDE_INT alignment)
 
   if (GET_CODE (symref) == SYMBOL_REF)
     {
+      /* s390_encode_section_info is not called for anchors, since they don't
+	 have corresponding VAR_DECLs.  Therefore, we cannot rely on
+	 SYMBOL_FLAG_NOTALIGN{2,4,8}_P returning useful information.  */
+      if (SYMBOL_REF_ANCHOR_P (symref))
+	{
+	  HOST_WIDE_INT block_offset = SYMBOL_REF_BLOCK_OFFSET (symref);
+	  unsigned int block_alignment = (SYMBOL_REF_BLOCK (symref)->alignment
+					  / BITS_PER_UNIT);
+
+	  gcc_assert (block_offset >= 0);
+	  return ((block_offset & (alignment - 1)) == 0
+		  && block_alignment >= alignment);
+	}
+
       /* We have load-relative instructions for 2-byte, 4-byte, and
 	 8-byte alignment so allow only these.  */
       switch (alignment)
@@ -16338,6 +16352,11 @@  s390_case_values_threshold (void)
 #undef TARGET_CASE_VALUES_THRESHOLD
 #define TARGET_CASE_VALUES_THRESHOLD s390_case_values_threshold
 
+/* Use only short displacement, since long displacement is not available for
+   the floating point instructions.  */
+#undef TARGET_MAX_ANCHOR_OFFSET
+#define TARGET_MAX_ANCHOR_OFFSET 0xfff
+
 struct gcc_target targetm = TARGET_INITIALIZER;
 
 #include "gt-s390.h"
diff --git a/gcc/output.h b/gcc/output.h
index 333389e484c..b2f0cc168eb 100644
--- a/gcc/output.h
+++ b/gcc/output.h
@@ -219,7 +219,7 @@  extern void assemble_external (tree);
 extern void assemble_zeros (unsigned HOST_WIDE_INT);
 
 /* Assemble an alignment pseudo op for an ALIGN-bit boundary.  */
-extern void assemble_align (int);
+extern void assemble_align (unsigned int);
 
 /* Assemble a string constant with the specified C string as contents.  */
 extern void assemble_string (const char *, int);
diff --git a/gcc/testsuite/gcc.target/s390/nodatarel-1.c b/gcc/testsuite/gcc.target/s390/nodatarel-1.c
index 1d589a10947..f53332f901d 100644
--- a/gcc/testsuite/gcc.target/s390/nodatarel-1.c
+++ b/gcc/testsuite/gcc.target/s390/nodatarel-1.c
@@ -29,7 +29,7 @@  bar (int b)
   a = b;
 }
 
-/* { dg-final { scan-assembler-times "a@GOTENT" 3 } } */
+/* { dg-final { scan-assembler-times "\\.LANCHOR\\d+@GOTENT" 3 } } */
 
 /* The exrl target is a label_ref which should not be affected at
    all.  */
diff --git a/gcc/testsuite/gcc.target/s390/section-anchors.c b/gcc/testsuite/gcc.target/s390/section-anchors.c
new file mode 100644
index 00000000000..68a6a393e31
--- /dev/null
+++ b/gcc/testsuite/gcc.target/s390/section-anchors.c
@@ -0,0 +1,14 @@ 
+/* Test basic section anchor functionality.  */
+
+/* { dg-do compile { target { lp64 } } } */
+/* { dg-options "-O3 -march=z13" } */
+
+int a = 1, b = 2;
+
+void
+f ()
+{
+  a = 1234;
+  b = 5678;
+  /* { dg-final { scan-assembler {(?n)\n\tlarl\t(%r\d+),\.LANCHOR\d+\n\tmvhi\t\d+\(\1\),1234\n\tmvhi\t\d+\(\1\),5678} } } */
+}
diff --git a/gcc/testsuite/gcc.target/s390/section-anchors2.c b/gcc/testsuite/gcc.target/s390/section-anchors2.c
new file mode 100644
index 00000000000..a3c31432d7a
--- /dev/null
+++ b/gcc/testsuite/gcc.target/s390/section-anchors2.c
@@ -0,0 +1,26 @@ 
+/* Test corner case when LG from literal pool could be preferred to LARL.  */
+
+/* { dg-do compile { target { lp64 } } } */
+/* { dg-options "-O3 -march=z13" } */
+
+int e = 42;
+int *c = &e;
+
+void
+h (int *i)
+{
+  c = i;
+}
+
+void
+j ()
+{
+  h (&e);
+  /* { dg-final { scan-assembler {(?n)\n\tlarl\t.+\n\tstgrl\t.+\n\tbr\t%r14\n} } } */
+}
+
+void
+f ()
+{
+  h (c);
+}
diff --git a/gcc/testsuite/gcc.target/s390/section-anchors3.c b/gcc/testsuite/gcc.target/s390/section-anchors3.c
new file mode 100644
index 00000000000..d9cac9d7e57
--- /dev/null
+++ b/gcc/testsuite/gcc.target/s390/section-anchors3.c
@@ -0,0 +1,11 @@ 
+/* Test corner case when LG from literal pool could be preferred to LARL.  */
+
+/* { dg-do compile { target { lp64 } } } */
+/* { dg-options "-O3 -march=z13" } */
+
+int
+a (int b)
+{
+  return b / 100;
+  /* { dg-final { scan-assembler-not {\n\t\.quad\t\.LC} } } */
+}
diff --git a/gcc/varasm.c b/gcc/varasm.c
index 243d205c1f5..dcce541d643 100644
--- a/gcc/varasm.c
+++ b/gcc/varasm.c
@@ -1974,7 +1974,7 @@  assemble_zeros (unsigned HOST_WIDE_INT size)
 /* Assemble an alignment pseudo op for an ALIGN-bit boundary.  */
 
 void
-assemble_align (int align)
+assemble_align (unsigned int align)
 {
   if (align > BITS_PER_UNIT)
     {