On 2/14/25 18:11, Michael Clark wrote:
the intent of this patch is more conventional nomenclature
but the constant pool data code is also simplified a little.
- merge new_pool_{alloc,insert} -> new_pool_data.
- rename TCGLabelPoolData -> TCGData.
- rename pool_labels -> pool_data.
- rename macro TCG_TARGET_NEED_POOL_DATA.
- move TCGData struct definition into tcg.h.
- comment translation block epilogue members.
You can see from this list that this should be multiple patches.
TCGLabelPoolData is ambiguous and asks for potential confusion
with the unrelated TCGLabel type. there is no label in the sense
of TCGLabel.
Fair.
the label member is merely a pointer to the instruction text to
be updated with the relative address of the constant, the primary
data is the constant data pool at the end of translation blocks.
this relates more closely to .data sections in offline codegen
if we were to imagine a translation block has .text and .data.
No, it doesn't. It relates most closely to data emitted within .text, accessed via
pc-relative instructions with limited offsets.
This isn't a thing you'd have ever seen on x86 or x86_64, but it is quite common for arm32
(12-bit offsets), sh4 (8-bit offsets), m68k (16-bit offsets) and such. Because the
offsets are so small, they could even be placed *within* functions not just between them.
thus TCGData is more succinct and more reflective of what the
structure contains; data emitted in the constant data pool at
the end of translation blocks. also, pool_labels is renamed to
pool_data as the primary contents of the list is constant data.
I guess. TCGData is perhaps too short, but we can certainly avoid the confusion of
"labels".
finally, new_pool_alloc and new_pool_insert are merged into a
single function named new_pool_data, which moves nlongs to the
end of the parameter list with varargs to allocate, copy, and
insert constant data items to simplify new_pool_label et al.
a successive step would be to collapse callers into calling
new_pool_data and remove a layer of indirection.
Why? varargs generally produces horrible code.
The split between alloc and insert was intentional to avoid this.
diff --git a/tcg/tci/tcg-target.h b/tcg/tci/tcg-target.h
index a9ca493d20f6..448c2330ef0f 100644
--- a/tcg/tci/tcg-target.h
+++ b/tcg/tci/tcg-target.h
@@ -72,6 +72,6 @@ typedef enum {
} TCGReg;
#define HAVE_TCG_QEMU_TB_EXEC
-#define TCG_TARGET_NEED_POOL_LABELS
+#define TCG_TARGET_NEED_POOL_DATA
Oops, this should have been removed with a417ef83.
r~
