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[PATCH] Fix sparc libm when all of glibc is built with-frounding-math.
- From: David Miller <davem at davemloft dot net>
- To: libc-alpha at sourceware dot org
- Date: Mon, 07 May 2012 22:28:37 -0400 (EDT)
- Subject: [PATCH] Fix sparc libm when all of glibc is built with-frounding-math.
Committed to master.
[BZ #14074]
* sysdeps/sparc/sysdep.h (SPARC_PIC_THUNK_CALL): New macro.
(SETUP_PIC_REG): Use it.
(SETUP_PIC_REG_LEAF): Use it.
---
ChangeLog | 7 +++++++
sysdeps/sparc/sysdep.h | 25 +++++++++++++++++++------
2 files changed, 26 insertions(+), 6 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index b80b485..ab0b7cf 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2012-05-07 David S. Miller <davem@davemloft.net>
+
+ [BZ #14074]
+ * sysdeps/sparc/sysdep.h (SPARC_PIC_THUNK_CALL): New macro.
+ (SETUP_PIC_REG): Use it.
+ (SETUP_PIC_REG_LEAF): Use it.
+
2012-05-07 Joseph Myers <joseph@codesourcery.com>
[BZ #13885]
diff --git a/sysdeps/sparc/sysdep.h b/sysdeps/sparc/sysdep.h
index 2702620..bcffec9 100644
--- a/sysdeps/sparc/sysdep.h
+++ b/sysdeps/sparc/sysdep.h
@@ -58,21 +58,34 @@ __sparc_get_pc_thunk.reg: \
.previous; \
.endif;
-/* Even when v9 we use a call sequence instead of using "rd %pc" because
+/* The "-4" and "+4" offsets against _GLOBAL_OFFSET_TABLE_ are
+ critical since they represent the offset from the thunk call to the
+ instruction containing the _GLOBAL_OFFSET_TABLE_ reference.
+ Therefore these instructions cannot be moved around without
+ appropriate adjustments to those offsets.
+
+ Furthermore, these expressions are special in another regard. When
+ the assembler sees a reference to _GLOBAL_OFFSET_TABLE_ inside of
+ a %hi() or %lo(), it emits a PC-relative relocation. This causes
+ R_SPARC_HI22 to turn into R_SPARC_PC22, and R_SPARC_LO10 to turn into
+ R_SPARC_PC10, respectively.
+
+ Even when v9 we use a call sequence instead of using "rd %pc" because
RDPC is extremely expensive and incurs a full pipeline flush. */
-#define SETUP_PIC_REG(reg) \
- SPARC_PIC_THUNK(reg) \
+#define SPARC_PIC_THUNK_CALL(reg) \
sethi %hi(_GLOBAL_OFFSET_TABLE_-4), %##reg; \
call __sparc_get_pc_thunk.reg; \
or %##reg, %lo(_GLOBAL_OFFSET_TABLE_+4), %##reg;
+#define SETUP_PIC_REG(reg) \
+ SPARC_PIC_THUNK(reg) \
+ SPARC_PIC_THUNK_CALL(reg)
+
#define SETUP_PIC_REG_LEAF(reg, tmp) \
SPARC_PIC_THUNK(reg) \
- sethi %hi(_GLOBAL_OFFSET_TABLE_-4), %##reg; \
mov %o7, %##tmp; \
- call __sparc_get_pc_thunk.reg; \
- or %##reg, %lo(_GLOBAL_OFFSET_TABLE_+4), %##reg; \
+ SPARC_PIC_THUNK_CALL(reg); \
mov %##tmp, %o7;
#undef ENTRY
--
1.7.10