On 10/20/2015 03:27 PM, Richard Henderson wrote:
---
gcc/config/i386/i386.c | 21 +++++++++++++++++++++
gcc/doc/tm.texi | 7 +++++++
gcc/doc/tm.texi.in | 2 ++
gcc/dwarf2out.c | 48 +++++++++++++++++++++++++++++-------------------
gcc/target.def | 10 ++++++++++
gcc/targhooks.c | 8 ++++++++
gcc/targhooks.h | 1 +
7 files changed, 78 insertions(+), 19 deletions(-)
diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index 8f833d1..9fb0fac 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -53707,6 +53707,27 @@ ix86_addr_space_convert (rtx op, tree from_type, tree
to_type)
#undef TARGET_ADDR_SPACE_CONVERT
#define TARGET_ADDR_SPACE_CONVERT ix86_addr_space_convert
+static int
+ix86_addr_space_debug (addr_space_t as)
+{
+ /* Represent debugging for address spaces with DW_AT_segment,
+ and the dwarf register for fsbase/gsbase. */
+ if (as == ADDR_SPACE_SEG_TLS)
+ as = DEFAULT_TLS_SEG_REG;
+
+ /* ??? These register numbers are defined in the x86-64 abi,
+ but there is no corresponding definition for the i386 abi.
+ That said, {58,59} appear to be reserved, so perhaps best
+ to use the same numbers in the 32-bit abi. */
+ if (as == ADDR_SPACE_SEG_FS)
+ return ~58; /* dwarf fsbase */
+ else if (as == ADDR_SPACE_SEG_GS)
+ return ~59; /* dwarf gsbase */
+ gcc_unreachable ();
+}
So in the case where AS, as passed in is ADDR_SPACE_SEG_TLS, we then
change it to DEFAULT_TLS_SEG_REG.
Yet I don't see DEFAULT_TLS_SEG_REG handled in the two cases below which
would make one think we'd hit the gcc_unreachable (). Of course
DEFAULT_TLS_SEG_REG will be defined as ADDR_SPACE_SEG_FS or
ADDR_SPACE_SEG_GS, so we can't actually hit the gcc_unreachable, but
as-written that's non-obvious.
If you could clarify that with a comment I think this hunk is ready to go.
jeff
