[PATCH v2] LoongArch: gas: Try to avoid R_LARCH_ALIGN associate with a symbol

[PATCH v2] LoongArch: gas: Try to avoid R_LARCH_ALIGN associate with a symbol

[mengqinggang]

The R_LARCH_ALIGN need to associated with a symbol if .align has the first
and third expressions. If R_LARCH_ALIGN associate with a symbol, the addend can
represent the first and third expression of .align.

For '.align 3', the addend of R_LARCH_ALIGN only need to represent the alignment
and R_LARCH_ALIGN not need to associate with a symbol.

For '.align x, , y', R_LARCH_ALIGN need to associate with a symbol if 0 < y <
2^x - 4.
---
v1 -> v2:
- For '.align x, , y', R_LARCH_ALIGN need to associate with a symbol if 0 < y <
  2^x - 4.

v1 link: https://sourceware.org/pipermail/binutils/2024-February/132306.html

 gas/config/tc-loongarch.c                 | 27 +++++++---
 gas/testsuite/gas/loongarch/relax_align.d | 64 +++++++++++++----------
 gas/testsuite/gas/loongarch/relax_align.s | 20 +++++--
 3 files changed, 72 insertions(+), 39 deletions(-)

diff --git a/gas/config/tc-loongarch.c b/gas/config/tc-loongarch.c
index 91f5f1d0681..de92366eda4 100644
--- a/gas/config/tc-loongarch.c
+++ b/gas/config/tc-loongarch.c
@@ -1746,14 +1746,25 @@ loongarch_frag_align_code (int n, int max)
 
   nops = frag_more (worst_case_bytes);
 
-  s = symbol_find (".Lla-relax-align");
-  if (s == NULL)
-    s = (symbolS *)local_symbol_make (".Lla-relax-align", now_seg,
-				      &zero_address_frag, 0);
-
-  ex.X_add_symbol = s;
-  ex.X_op = O_symbol;
-  ex.X_add_number = (max << 8) | n;
+  /* If max <= 0, ignore max.
+     If max >= worst_case_bytes, max has no effect.
+     Similar to gas/write.c relax_segment function rs_align_code case:
+     if (fragP->fr_subtype != 0 && offset > fragP->fr_subtype).  */
+  if (max > 0 && (bfd_vma) max < worst_case_bytes)
+    {
+      s = symbol_find (".Lla-relax-align");
+      if (s == NULL)
+	s = (symbolS *)local_symbol_make (".Lla-relax-align", now_seg,
+					  &zero_address_frag, 0);
+      ex.X_add_symbol = s;
+      ex.X_op = O_symbol;
+      ex.X_add_number = (max << 8) | n;
+    }
+  else
+    {
+      ex.X_op = O_constant;
+      ex.X_add_number = worst_case_bytes;
+    }
 
   loongarch_make_nops (nops, worst_case_bytes);
 
diff --git a/gas/testsuite/gas/loongarch/relax_align.d b/gas/testsuite/gas/loongarch/relax_align.d
index 2cc6c86d38a..fc1fd032611 100644
--- a/gas/testsuite/gas/loongarch/relax_align.d
+++ b/gas/testsuite/gas/loongarch/relax_align.d
@@ -1,4 +1,4 @@
-#as: --no-warn
+#as:
 #objdump: -dr
 #skip: loongarch32-*-*
 
@@ -8,29 +8,39 @@
 Disassembly of section .text:
 
 [ 	]*0000000000000000 <.Lla-relax-align>:
-[ 	]+0:[ 	]+1a000004[ 	]+pcalau12i[ 	]+\$a0, 0
-[ 	]+0: R_LARCH_PCALA_HI20[ 	]+L1
-[ 	]+0: R_LARCH_RELAX[ 	]+\*ABS\*
-[ 	]+4:[ 	]+02c00084[ 	]+addi.d[ 	]+\$a0, \$a0, 0
-[ 	]+4: R_LARCH_PCALA_LO12[ 	]+L1
-[ 	]+4: R_LARCH_RELAX[ 	]+\*ABS\*
-[ 	]+8:[ 	]+03400000[ 	]+nop.*
-[ 	]+8: R_LARCH_ALIGN[ 	]+.Lla-relax-align\+0x4
-[ 	]+c:[ 	]+03400000[ 	]+nop.*
-[ 	]+10:[ 	]+03400000[ 	]+nop.*
-[ 	]+14:[ 	]+1a000004[ 	]+pcalau12i[ 	]+\$a0, 0
-[ 	]+14: R_LARCH_PCALA_HI20[ 	]+L1
-[ 	]+14: R_LARCH_RELAX[ 	]+\*ABS\*
-[ 	]+18:[ 	]+02c00084[ 	]+addi.d[ 	]+\$a0, \$a0, 0
-[ 	]+18: R_LARCH_PCALA_LO12[ 	]+L1
-[ 	]+18: R_LARCH_RELAX[ 	]+\*ABS\*
-[ 	]+1c:[ 	]+03400000[ 	]+nop.*
-[ 	]+1c: R_LARCH_ALIGN[ 	]+.Lla-relax-align\+0x404
-[ 	]+20:[ 	]+03400000[ 	]+nop.*
-[ 	]+24:[ 	]+03400000[ 	]+nop.*
-[ 	]+28:[ 	]+1a000004[ 	]+pcalau12i[ 	]+\$a0, 0
-[ 	]+28: R_LARCH_PCALA_HI20[ 	]+L1
-[ 	]+28: R_LARCH_RELAX[ 	]+\*ABS\*
-[ 	]+2c:[ 	]+02c00084[ 	]+addi.d[ 	]+\$a0, \$a0, 0
-[ 	]+2c: R_LARCH_PCALA_LO12[ 	]+L1
-[ 	]+2c: R_LARCH_RELAX[ 	]+\*ABS\*
+[ 	]+0:[ 	]+4c000020[ 	]+ret
+[ 	]+4:[ 	]+03400000[ 	]+nop
+[ 	]+4: R_LARCH_ALIGN[ 	]+\*ABS\*\+0xc
+[ 	]+8:[ 	]+03400000[ 	]+nop
+[ 	]+c:[ 	]+03400000[ 	]+nop
+[ 	]+10:[ 	]+4c000020[ 	]+ret
+[ 	]+14:[ 	]+03400000[ 	]+nop
+[ 	]+14: R_LARCH_ALIGN[ 	]+\*ABS\*\+0xc
+[ 	]+18:[ 	]+03400000[ 	]+nop
+[ 	]+1c:[ 	]+03400000[ 	]+nop
+[ 	]+20:[ 	]+4c000020[ 	]+ret
+[ 	]+24:[ 	]+03400000[ 	]+nop
+[ 	]+24: R_LARCH_ALIGN[ 	]+.Lla-relax-align\+0x104
+[ 	]+28:[ 	]+03400000[ 	]+nop
+[ 	]+2c:[ 	]+03400000[ 	]+nop
+[ 	]+30:[ 	]+4c000020[ 	]+ret
+[ 	]+34:[ 	]+03400000[ 	]+nop
+[ 	]+34: R_LARCH_ALIGN[ 	]+.Lla-relax-align\+0xb04
+[ 	]+38:[ 	]+03400000[ 	]+nop
+[ 	]+3c:[ 	]+03400000[ 	]+nop
+[ 	]+40:[ 	]+4c000020[ 	]+ret
+[ 	]+44:[ 	]+03400000[ 	]+nop
+[ 	]+44: R_LARCH_ALIGN[ 	]+\*ABS\*\+0xc
+[ 	]+48:[ 	]+03400000[ 	]+nop
+[ 	]+4c:[ 	]+03400000[ 	]+nop
+[ 	]+50:[ 	]+4c000020[ 	]+ret
+[ 	]+54:[ 	]+03400000[ 	]+nop
+[ 	]+54: R_LARCH_ALIGN[ 	]+\*ABS\*\+0xc
+[ 	]+58:[ 	]+03400000[ 	]+nop
+[ 	]+5c:[ 	]+03400000[ 	]+nop
+[ 	]+60:[ 	]+4c000020[ 	]+ret
+[ 	]+64:[ 	]+03400000[ 	]+nop
+[ 	]+64: R_LARCH_ALIGN[ 	]+\*ABS\*\+0xc
+[ 	]+68:[ 	]+03400000[ 	]+nop
+[ 	]+6c:[ 	]+03400000[ 	]+nop
+[ 	]+70:[ 	]+4c000020[ 	]+ret
diff --git a/gas/testsuite/gas/loongarch/relax_align.s b/gas/testsuite/gas/loongarch/relax_align.s
index c0177c88fc1..4f4867fb209 100644
--- a/gas/testsuite/gas/loongarch/relax_align.s
+++ b/gas/testsuite/gas/loongarch/relax_align.s
@@ -1,7 +1,19 @@
+# If max < -0x80000000, max becomes a positive number because type conversion
+# (bfd_signed_vma -> unsigned int).
   .text
 .L1:
-  la.local $a0, L1
+  ret
   .align 4
-  la.local $a0, L1
-  .align 4, , 4
-  la.local $a0, L1
+  ret
+  .align 4, , 0
+  ret
+  .align 4, , 1
+  ret
+  .align 4, , 11
+  ret
+  .align 4, , 12
+  ret
+  .align 4, , -1
+  ret
+  .align 4, , -0x80000000
+  ret
-- 
2.36.0