[PATCH] Add srodata section support to riscv port.

[Jim Wilson <jimw at sifive dot com>]

This adds srodata section support to the RISC-V port, putting small read-only
data in the .srodata section instead of the .sdata section.  There is already
code to put small read-only rtx in .srodata* instead of .rodata*.  This
does the same for small read-only trees to be consistent.

Tested with a rv32gc/ilp32 make check.  There were no regressions.  Committed.

2017-12-07  Andrew Waterman  <andrew@sifive.com>

	gcc/
	* config/riscv/riscv.c (TARGET_ASM_SELECT_SECTION): New define.
	(TARGET_HAVE_SRODATA_SECTION): New define.
	(riscv_select_section): New function.
---
 gcc/config/riscv/riscv.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/gcc/config/riscv/riscv.c b/gcc/config/riscv/riscv.c
index c7283d02141..cfab2e77686 100644
--- a/gcc/config/riscv/riscv.c
+++ b/gcc/config/riscv/riscv.c
@@ -3042,6 +3042,22 @@ riscv_in_small_data_p (const_tree x)
   return riscv_size_ok_for_small_data_p (int_size_in_bytes (TREE_TYPE (x)));
 }
 
+/* Switch to the appropriate section for output of DECL.  */
+
+static section *
+riscv_select_section (tree decl, int reloc,
+		      unsigned HOST_WIDE_INT align)
+{
+  switch (categorize_decl_for_section (decl, reloc))
+    {
+    case SECCAT_SRODATA:
+      return get_named_section (decl, ".srodata", reloc);
+
+    default:
+      return default_elf_select_section (decl, reloc, align);
+    }
+}
+
 /* Return a section for X, handling small data. */
 
 static section *
@@ -4320,6 +4336,12 @@ riscv_constant_alignment (const_tree exp, HOST_WIDE_INT align)
 #undef TARGET_IN_SMALL_DATA_P
 #define TARGET_IN_SMALL_DATA_P riscv_in_small_data_p
 
+#undef TARGET_HAVE_SRODATA_SECTION
+#define TARGET_HAVE_SRODATA_SECTION true
+
+#undef TARGET_ASM_SELECT_SECTION
+#define TARGET_ASM_SELECT_SECTION riscv_select_section
+
 #undef TARGET_ASM_SELECT_RTX_SECTION
 #define TARGET_ASM_SELECT_RTX_SECTION  riscv_elf_select_rtx_section
 
-- 
2.14.1