diff mbox series

Hexagon (target/hexagon) Only pass env to generated helper when needed

Message ID 20240202194842.148085-1-ltaylorsimpson@gmail.com (mailing list archive)
State New, archived
Headers show
Series Hexagon (target/hexagon) Only pass env to generated helper when needed | expand

Commit Message

Taylor Simpson Feb. 2, 2024, 7:48 p.m. UTC
Currently, we pass env to every generated helper.  When the semantics of
the instruction only depend on the arguments, this is unnecessary and
adds extra overhead to the helper call.

The A2_nop and SA1_setin1 instructions end up with no arguments.  This
results in a "old-style function definition" error from the compiler, so
we write overrides for them.

With this change, the number of helpers with env argument is
    idef-parser enabled:    329 total, 23 with env
    idef-parser disabled:   1543 total, 553 with env

Signed-off-by: Taylor Simpson <ltaylorsimpson@gmail.com>
---
 target/hexagon/gen_tcg.h         |  3 +++
 target/hexagon/attribs_def.h.inc |  1 +
 target/hexagon/hex_common.py     | 22 +++++++++++++++++-----
 3 files changed, 21 insertions(+), 5 deletions(-)
diff mbox series

Patch

diff --git a/target/hexagon/gen_tcg.h b/target/hexagon/gen_tcg.h
index 1c4391b415..e9ac2e3fe0 100644
--- a/target/hexagon/gen_tcg.h
+++ b/target/hexagon/gen_tcg.h
@@ -1369,3 +1369,6 @@ 
         gen_helper_raise_exception(tcg_env, excp); \
     } while (0)
 #endif
+
+#define fGEN_TCG_A2_nop(SHORTCODE) do { } while (0)
+#define fGEN_TCG_SA1_setin1(SHORTCODE) tcg_gen_movi_tl(RdV, -1)
diff --git a/target/hexagon/attribs_def.h.inc b/target/hexagon/attribs_def.h.inc
index 87942d46f4..8949ee09cf 100644
--- a/target/hexagon/attribs_def.h.inc
+++ b/target/hexagon/attribs_def.h.inc
@@ -117,6 +117,7 @@  DEF_ATTRIB(IMPLICIT_READS_P1, "Reads the P1 register", "", "")
 DEF_ATTRIB(IMPLICIT_READS_P2, "Reads the P2 register", "", "")
 DEF_ATTRIB(IMPLICIT_READS_P3, "Reads the P3 register", "", "")
 DEF_ATTRIB(IMPLICIT_WRITES_USR, "May write USR", "", "")
+DEF_ATTRIB(IMPLICIT_READS_SP, "Reads the SP register", "", "")
 DEF_ATTRIB(COMMUTES, "The operation is communitive", "", "")
 DEF_ATTRIB(DEALLOCRET, "dealloc_return", "", "")
 DEF_ATTRIB(DEALLOCFRAME, "deallocframe", "", "")
diff --git a/target/hexagon/hex_common.py b/target/hexagon/hex_common.py
index 195620c7ec..12bc410bb2 100755
--- a/target/hexagon/hex_common.py
+++ b/target/hexagon/hex_common.py
@@ -101,6 +101,7 @@  def calculate_attribs():
     add_qemu_macro_attrib('fLSBNEW1', 'A_IMPLICIT_READS_P1')
     add_qemu_macro_attrib('fLSBNEW1NOT', 'A_IMPLICIT_READS_P1')
     add_qemu_macro_attrib('fREAD_P3', 'A_IMPLICIT_READS_P3')
+    add_qemu_macro_attrib('fREAD_SP', 'A_IMPLICIT_READS_SP')
 
     # Recurse down macros, find attributes from sub-macros
     macroValues = list(macros.values())
@@ -197,6 +198,16 @@  def get_tagimms():
     return dict(zip(tags, list(map(compute_tag_immediates, tags))))
 
 
+def need_env(tag):
+    return ("A_STORE" in attribdict[tag] or
+            "A_LOAD" in attribdict[tag] or
+            "A_CVI_GATHER" in attribdict[tag] or
+            "A_CVI_SCATTER" in attribdict[tag] or
+            "A_IMPLICIT_WRITES_USR" in attribdict[tag] or
+            "A_IMPLICIT_READS_P0" in attribdict[tag] or
+            "A_IMPLICIT_READS_SP" in attribdict[tag])
+
+
 def need_slot(tag):
     if (
         "A_CVI_SCATTER" not in attribdict[tag]
@@ -1060,11 +1071,12 @@  def helper_args(tag, regs, imms):
     args = []
 
     ## First argument is the CPU state
-    args.append(HelperArg(
-        "env",
-        "tcg_env",
-        "CPUHexagonState *env"
-    ))
+    if need_env(tag):
+        args.append(HelperArg(
+            "env",
+            "tcg_env",
+            "CPUHexagonState *env"
+        ))
 
     ## For predicated instructions, we pass in the destination register
     if is_predicated(tag):