[llvm-branch-commits] [lld] [lld][LoongArch] Relax call36/tail36: R_LARCH_CALL36 (PR #123576)
Zhaoxin Yang via llvm-branch-commits
llvm-branch-commits at lists.llvm.org
Mon Jan 20 01:56:44 PST 2025
https://github.com/ylzsx created https://github.com/llvm/llvm-project/pull/123576
Instructions with relocation `R_LARCH_CALL36` may be relax as follows:
```
From:
pcaddu18i $dest, %call36(foo)
R_LARCH_CALL36, R_LARCH_RELAX
jirl $r, $dest, 0
To:
b/bl foo # bl if r=$ra, b if r=$zero
R_LARCH_B26
```
>From f1f995b5fc8e90126b5825d52b9c75cd45d27cfc Mon Sep 17 00:00:00 2001
From: yangzhaoxin <yangzhaoxin at loongson.cn>
Date: Thu, 26 Dec 2024 11:32:33 +0800
Subject: [PATCH 1/3] Relax call36/tail36.
Instructions with relocation `R_LARCH_CALL36` may be relax as follows:
```
From:
pcaddu18i $dest, %call36(foo)
R_LARCH_CALL36, R_LARCH_RELAX
jirl $r, $dest, 0
To:
b/bl foo # bl if r=$ra, b if r=$zero
R_LARCH_B26
```
---
lld/ELF/Arch/LoongArch.cpp | 41 ++++++++++++++++++++++++++++++++++++++
1 file changed, 41 insertions(+)
diff --git a/lld/ELF/Arch/LoongArch.cpp b/lld/ELF/Arch/LoongArch.cpp
index b999e7fd27ae9d..0aa0cf5b657a0f 100644
--- a/lld/ELF/Arch/LoongArch.cpp
+++ b/lld/ELF/Arch/LoongArch.cpp
@@ -58,6 +58,8 @@ enum Op {
LD_W = 0x28800000,
LD_D = 0x28c00000,
JIRL = 0x4c000000,
+ B = 0x50000000,
+ BL = 0x54000000,
};
enum Reg {
@@ -830,6 +832,37 @@ static void relaxPCHi20Lo12(Ctx &ctx, const InputSection &sec, size_t i,
remove = 4;
}
+// Relax code sequence.
+// From:
+// pcaddu18i $ra, %call36(foo)
+// jirl $ra, $ra, 0
+// To:
+// b/bl foo
+static void relaxCall36(Ctx &ctx, const InputSection &sec, size_t i,
+ uint64_t loc, Relocation &r, uint32_t &remove) {
+ const uint64_t symLocal =
+ (r.expr == R_PLT_PC ? r.sym->getPltVA(ctx) : r.sym->getVA(ctx)) +
+ r.addend;
+
+ const int64_t distance = symLocal - loc;
+ // Check if the distance aligns 4 bytes or exceeds the range of b[l].
+ if ((distance & 0x3) != 0 || !isInt<28>(distance))
+ return;
+
+ const uint32_t nextInsn = read32le(sec.content().data() + r.offset + 4);
+ if (getD5(nextInsn) == R_RA) {
+ // convert jirl to bl
+ sec.relaxAux->relocTypes[i] = R_LARCH_B26;
+ sec.relaxAux->writes.push_back(insn(BL, 0, 0, 0));
+ remove = 4;
+ } else if (getD5(nextInsn) == R_ZERO) {
+ // convert jirl to b
+ sec.relaxAux->relocTypes[i] = R_LARCH_B26;
+ sec.relaxAux->writes.push_back(insn(B, 0, 0, 0));
+ remove = 4;
+ }
+}
+
static bool relax(Ctx &ctx, InputSection &sec) {
const uint64_t secAddr = sec.getVA();
const MutableArrayRef<Relocation> relocs = sec.relocs();
@@ -874,6 +907,10 @@ static bool relax(Ctx &ctx, InputSection &sec) {
if (isPairRelaxable(relocs, i))
relaxPCHi20Lo12(ctx, sec, i, loc, r, relocs[i + 2], remove);
break;
+ case R_LARCH_CALL36:
+ if (relaxable(relocs, i))
+ relaxCall36(ctx, sec, i, loc, r, remove);
+ break;
}
// For all anchors whose offsets are <= r.offset, they are preceded by
@@ -977,6 +1014,10 @@ void LoongArch::finalizeRelax(int passes) const {
// RelExpr is needed for relocating.
r.expr = r.sym->hasFlag(NEEDS_PLT) ? R_PLT_PC : R_PC;
break;
+ case R_LARCH_B26:
+ skip = 4;
+ write32le(p, aux.writes[writesIdx++]);
+ break;
default:
llvm_unreachable("unsupported type");
}
>From f227ae532236e20148a872c811721a8de4e16318 Mon Sep 17 00:00:00 2001
From: yangzhaoxin <yangzhaoxin at loongson.cn>
Date: Fri, 27 Dec 2024 14:37:40 +0800
Subject: [PATCH 2/3] modify test for call36/tail36.
---
lld/test/ELF/loongarch-relax-call36-2.s | 63 +++++++++
lld/test/ELF/loongarch-relax-call36.s | 135 +++++++++++++++++++
lld/test/ELF/loongarch-relax-emit-relocs-2.s | 61 +++++++++
3 files changed, 259 insertions(+)
create mode 100644 lld/test/ELF/loongarch-relax-call36-2.s
create mode 100644 lld/test/ELF/loongarch-relax-call36.s
create mode 100644 lld/test/ELF/loongarch-relax-emit-relocs-2.s
diff --git a/lld/test/ELF/loongarch-relax-call36-2.s b/lld/test/ELF/loongarch-relax-call36-2.s
new file mode 100644
index 00000000000000..1c216a9bdc35ed
--- /dev/null
+++ b/lld/test/ELF/loongarch-relax-call36-2.s
@@ -0,0 +1,63 @@
+# REQUIRES: loongarch
+# RUN: rm -rf %t && split-file %s %t && cd %t
+# RUN: llvm-mc -filetype=obj -triple=loongarch64 -mattr=+relax a.s -o a.o
+
+# RUN: ld.lld -T lds a.o -o a
+# RUN: llvm-objdump -d --no-show-raw-insn a | FileCheck %s --check-prefixes=RELAX,RELAX-MID
+
+## Unsure whether this needs a diagnostic. GNU ld allows this.
+# RUN: ld.lld -T lds -pie a.o -o a.pie
+# RUN: llvm-objdump -d --no-show-raw-insn a.pie | FileCheck %s --check-prefixes=RELAX,RELAX-MID
+
+# RUN: ld.lld -T lds -pie -z notext -z ifunc-noplt a.o -o a.ifunc-noplt
+# RUN: llvm-objdump -d --no-show-raw-insn a.ifunc-noplt | FileCheck %s --check-prefixes=RELAX,NORELAX-MID
+
+# RELAX-LABEL: <_start>:
+## offset = 0x10000000 - 0x8000000 = 0x8000000(134217728), hi=512, lo18=0
+# RELAX-NEXT: 8000000: pcaddu18i $ra, 512
+# RELAX-NEXT: jirl $ra, $ra, 0
+# RELAX-NEXT: bl 134217720
+# RELAX-NEXT: bl -134217728
+## offset = 12 - 0x8000010 = -0x8000004(-134217732), hi=512, lo18=-4
+# RELAX-NEXT: 8000010: pcaddu18i $ra, -512
+# RELAX-NEXT: jirl $ra, $ra, -4
+# RELAX-EMPTY:
+
+# RELAX-MID-LABEL: <.mid>:
+## offset = 0x8010000 - 0x8008000 = 32768
+# RELAX-MID-NEXT: 8008000: bl 32768
+# RELAX-MID-NEXT: b 32764
+# RELAX-MID-EMPTY:
+
+# NORELAX-MID-LABEL: <.mid>:
+# NORELAX-MID-NEXT: 8008000: pcaddu18i $ra, 0
+# NORELAX-MID-NEXT: jirl $ra, $ra, 0
+# NORELAX-MID-NEXT: pcaddu18i $t0, 0
+# NORELAX-MID-NEXT: jr $t0
+# NORELAX-MID-EMPTY:
+
+#--- a.s
+.global _start, ifunc
+_start:
+ call36 pos # exceed positive range (.text+0x7fffffc), not relaxed
+ call36 pos # relaxed
+ call36 neg # relaxed
+ call36 neg # exceed negative range (.text+16-0x8000000), not relaxed
+
+.section .mid,"ax", at progbits
+.balign 16
+ call36 ifunc at plt # enable ifunc, not relaxed
+ tail36 $t0, ifunc at plt # enable ifunc, not relaxed
+
+.type ifunc, @gnu_indirect_function
+ifunc:
+ ret
+
+#--- lds
+SECTIONS {
+ .text 0x8000000 : { *(.text) }
+ .mid 0x8008000 : { *(.mid) }
+ .iplt 0x8010000 : { *(.iplt) }
+}
+neg = 12;
+pos = 0x10000000;
diff --git a/lld/test/ELF/loongarch-relax-call36.s b/lld/test/ELF/loongarch-relax-call36.s
new file mode 100644
index 00000000000000..57ed214c9eb2ed
--- /dev/null
+++ b/lld/test/ELF/loongarch-relax-call36.s
@@ -0,0 +1,135 @@
+# REQUIRES: loongarch
+
+# RUN: rm -rf %t && split-file %s %t && cd %t
+
+# RUN: llvm-mc -filetype=obj -triple=loongarch64 -mattr=+relax a.s -o a.64.o
+# RUN: llvm-mc -filetype=obj -triple=loongarch64 -mattr=+relax b.s -o b.64.o
+# RUN: ld.lld -shared -soname=b.so b.64.o -o b.64.so
+# RUN: ld.lld -T lds a.64.o b.64.so -o 64
+# RUN: llvm-objdump -td --no-show-raw-insn 64 | FileCheck %s --check-prefix=RELAX
+
+## --no-relax disables relaxation.
+# RUN: ld.lld -T lds a.64.o b.64.so --no-relax -o 64.norelax
+# RUN: llvm-objdump -td --no-show-raw-insn 64.norelax | FileCheck %s --check-prefix=NORELAX
+
+# RELAX: {{0*}}00010000 g .text {{0*}}0000001c _start
+# RELAX: {{0*}}0001001c g .text {{0*}}00000000 _start_end
+# RELAX: {{0*}}00010808 g .mid {{0*}}00000000 mid_end
+# RELAX: {{0*}}10010010 g .high {{0*}}00000000 high_end
+
+# RELAX-LABEL: <_start>:
+## offset = 0x10018 - 0x10000 = 24
+# RELAX-NEXT: 10000: bl 24 <a>
+# RELAX-NEXT: b 20 <a>
+# RELAX-NEXT: nop
+# RELAX-NEXT: nop
+## offset = .plt(0x10400)+32 - 0x10010 = 1040
+# RELAX-NEXT: 10010: bl 1040 <bar+0x10420>
+# RELAX-NEXT: b 1036 <bar+0x10420>
+# RELAX-EMPTY:
+# RELAX-NEXT: <a>:
+# RELAX-NEXT: 10018: ret
+# RELAX-EMPTY:
+
+# RELAX-LABEL: <.mid>:
+## offset = 0x10000 - 0x10800 = -2048
+# RELAX-NEXT: 10800: bl -2048 <_start>
+# RELAX-NEXT: b -2052 <_start>
+# RELAX-EMPTY:
+
+# RELAX-LABEL: <.mid2>:
+## offset = 0x10000 - 0x1010000 = -16777216
+# RELAX-NEXT: 1010000: bl -16777216 <_start>
+# RELAX-NEXT: b -16777220 <_start>
+# RELAX-EMPTY:
+
+# RELAX-LABEL: <.high>:
+## offset = 0x10000 - 0x10010000 = -0x10000000, hi=-1024, lo18=0
+# RELAX-NEXT: 10010000: pcaddu18i $ra, -1024
+# RELAX-NEXT: jirl $ra, $ra, 0
+# RELAX-NEXT: pcaddu18i $t0, -1024
+# RELAX-NEXT: jirl $zero, $t0, -8
+# RELAX-EMPTY:
+
+
+# NORELAX-LABEL: <_start>:
+## offset = 0x10020 - 0x10000 = 0x20, hi=0, lo18=32
+# NORELAX-NEXT: 10000: pcaddu18i $ra, 0
+# NORELAX-NEXT: jirl $ra, $ra, 32
+## offset = 0x10020 - 0x10008 = 0x18, hi=0, lo18=24
+# NORELAX-NEXT: 10008: pcaddu18i $t0, 0
+# NORELAX-NEXT: jirl $zero, $t0, 24
+## offset = .plt(0x10400)+32 - 0x10010 = 0x410, hi=0, lo18=1040
+# NORELAX-NEXT: 10010: pcaddu18i $ra, 0
+# NORELAX-NEXT: jirl $ra, $ra, 1040
+## offset = .plt(0x10400)+32 - 0x10018 = 0x408, hi=0, lo18=1032
+# NORELAX-NEXT: 10018: pcaddu18i $t0, 0
+# NORELAX-NEXT: jirl $zero, $t0, 1032
+# NORELAX-EMPTY:
+# NORELAX-NEXT: <a>:
+# NORELAX-NEXT: 10020: ret
+# NORELAX-EMPTY:
+
+# NORELAX-LABEL: <.mid>:
+## offset = 0x10000 - 0x10800 = -0x800, hi=0, lo18=-2048
+# NORELAX-NEXT: 10800: pcaddu18i $ra, 0
+# NORELAX-NEXT: jirl $ra, $ra, -2048
+# NORELAX-NEXT: pcaddu18i $t0, 0
+# NORELAX-NEXT: jirl $zero, $t0, -2056
+# NORELAX-EMPTY:
+
+# NORELAX-LABEL: <.mid2>:
+## offset = 0x10000 - 0x1010000 = -0x1000000, hi=-64, lo18=0
+# NORELAX-NEXT: 1010000: pcaddu18i $ra, -64
+# NORELAX-NEXT: jirl $ra, $ra, 0
+# NORELAX-NEXT: pcaddu18i $t0, -64
+# NORELAX-NEXT: jirl $zero, $t0, -8
+# NORELAX-EMPTY:
+
+# NORELAX-LABEL: <.high>:
+## offset = 0x10000 - 0x10010000 = -0x10000000, hi=-1024, lo18=0
+# NORELAX-NEXT: 10010000: pcaddu18i $ra, -1024
+# NORELAX-NEXT: jirl $ra, $ra, 0
+# NORELAX-NEXT: pcaddu18i $t0, -1024
+# NORELAX-NEXT: jirl $zero, $t0, -8
+# NORELAX-EMPTY:
+
+#--- a.s
+.global _start, _start_end
+_start:
+ call36 a # relaxed. la64: bl
+ tail36 $t0, a at plt # relaxed. la64: b
+.balign 16
+ call36 bar # PLT call36 can be relaxed. la64: bl
+ tail36 $t0, bar # PLT tail36 can be relaxed. la64: bl
+
+a:
+ ret
+.size _start, . - _start
+_start_end:
+
+.section .mid,"ax", at progbits
+ call36 _start at plt # relaxed. la64: bl
+ tail36 $t0, _start at plt # relaxed. la64: b
+
+.section .mid2,"ax", at progbits
+ call36 _start at plt # relaxed. la64: bl
+ tail36 $t0, _start at plt # relaxed. la64: b
+
+.section .high,"ax", at progbits
+ call36 _start at plt # exceed range, not relaxed
+ tail36 $t0,_start at plt # exceed range, not relaxed
+
+#--- b.s
+.globl bar
+bar:
+ ret
+
+#--- lds
+SECTIONS {
+ .text 0x10000 : { *(.text) }
+ .plt 0x10400 : { *(.plt) }
+ .mid 0x10800 : { *(.mid); mid_end = .; }
+ .mid2 0x1010000 : { *(.mid2) }
+ .high 0x10010000 : { *(.high); high_end = .; }
+}
diff --git a/lld/test/ELF/loongarch-relax-emit-relocs-2.s b/lld/test/ELF/loongarch-relax-emit-relocs-2.s
new file mode 100644
index 00000000000000..31cae939eca711
--- /dev/null
+++ b/lld/test/ELF/loongarch-relax-emit-relocs-2.s
@@ -0,0 +1,61 @@
+# REQUIRES: loongarch
+## Test that we can handle --emit-relocs while relaxing.
+## Call36 and tail36 need LA64 basic integer, so they donot have 32-bit version.
+
+# RUN: llvm-mc --filetype=obj --triple=loongarch64 --mattr=+relax %s -o %t.64.o
+# RUN: ld.lld -Ttext=0x10000 --emit-relocs %t.64.o -o %t.64
+# RUN: llvm-objdump -dr %t.64 | FileCheck %s --check-prefix=RELAX
+
+## -r should keep original relocations.
+# RUN: ld.lld -r %t.64.o -o %t.64.r
+# RUN: llvm-objdump -dr %t.64.r | FileCheck %s --check-prefix=CHECKR
+
+## --no-relax should keep original relocations.
+# RUN: ld.lld -Ttext=0x10000 --emit-relocs --no-relax %t.64.o -o %t.64.norelax
+# RUN: llvm-objdump -dr %t.64.norelax | FileCheck %s --check-prefix=NORELAX
+
+# RELAX: 00010000 <_start>:
+# RELAX-NEXT: bl 0
+# RELAX-NEXT: R_LARCH_B26 _start
+# RELAX-NEXT: R_LARCH_RELAX *ABS*
+# RELAX-NEXT: b -4
+# RELAX-NEXT: R_LARCH_B26 _start
+# RELAX-NEXT: R_LARCH_RELAX *ABS*
+# RELAX-NEXT: nop
+# RELAX-NEXT: R_LARCH_ALIGN *ABS*+0xc
+# RELAX-NEXT: nop
+# RELAX-NEXT: ret
+
+# CHECKR: <_start>:
+# CHECKR-NEXT: pcaddu18i $ra, 0
+# CHECKR-NEXT: R_LARCH_CALL36 _start
+# CHECKR-NEXT: R_LARCH_RELAX *ABS*
+# CHECKR-NEXT: jirl $ra, $ra, 0
+# CHECKR-NEXT: pcaddu18i $t0, 0
+# CHECKR-NEXT: R_LARCH_CALL36 _start
+# CHECKR-NEXT: R_LARCH_RELAX *ABS*
+# CHECKR-NEXT: jr $t0
+# CHECKR-NEXT: nop
+# CHECKR-NEXT: R_LARCH_ALIGN *ABS*+0xc
+# CHECKR-NEXT: nop
+# CHECKR-NEXT: nop
+# CHECKR-NEXT: ret
+
+# NORELAX: <_start>:
+# NORELAX-NEXT: pcaddu18i $ra, 0
+# NORELAX-NEXT: R_LARCH_CALL36 _start
+# NORELAX-NEXT: R_LARCH_RELAX *ABS*
+# NORELAX-NEXT: jirl $ra, $ra, 0
+# NORELAX-NEXT: pcaddu18i $t0, 0
+# NORELAX-NEXT: R_LARCH_CALL36 _start
+# NORELAX-NEXT: R_LARCH_RELAX *ABS*
+# NORELAX-NEXT: jirl $zero, $t0, -8
+# NORELAX-NEXT: ret
+# NORELAX-NEXT: R_LARCH_ALIGN *ABS*+0xc
+
+.global _start
+_start:
+ call36 _start
+ tail36 $t0, _start
+ .p2align 4
+ ret
>From f2aae15f701863d03edd32657824a97f66696e8d Mon Sep 17 00:00:00 2001
From: yangzhaoxin <yangzhaoxin at loongson.cn>
Date: Thu, 16 Jan 2025 21:50:14 +0800
Subject: [PATCH 3/3] Modify test. Add the option --relax.
---
lld/test/ELF/loongarch-relax-call36-2.s | 6 +++---
lld/test/ELF/loongarch-relax-call36.s | 6 +++---
lld/test/ELF/loongarch-relax-emit-relocs-2.s | 6 +++---
3 files changed, 9 insertions(+), 9 deletions(-)
diff --git a/lld/test/ELF/loongarch-relax-call36-2.s b/lld/test/ELF/loongarch-relax-call36-2.s
index 1c216a9bdc35ed..71650aefe94321 100644
--- a/lld/test/ELF/loongarch-relax-call36-2.s
+++ b/lld/test/ELF/loongarch-relax-call36-2.s
@@ -2,14 +2,14 @@
# RUN: rm -rf %t && split-file %s %t && cd %t
# RUN: llvm-mc -filetype=obj -triple=loongarch64 -mattr=+relax a.s -o a.o
-# RUN: ld.lld -T lds a.o -o a
+# RUN: ld.lld --relax -T lds a.o -o a
# RUN: llvm-objdump -d --no-show-raw-insn a | FileCheck %s --check-prefixes=RELAX,RELAX-MID
## Unsure whether this needs a diagnostic. GNU ld allows this.
-# RUN: ld.lld -T lds -pie a.o -o a.pie
+# RUN: ld.lld --relax -T lds -pie a.o -o a.pie
# RUN: llvm-objdump -d --no-show-raw-insn a.pie | FileCheck %s --check-prefixes=RELAX,RELAX-MID
-# RUN: ld.lld -T lds -pie -z notext -z ifunc-noplt a.o -o a.ifunc-noplt
+# RUN: ld.lld --relax -T lds -pie -z notext -z ifunc-noplt a.o -o a.ifunc-noplt
# RUN: llvm-objdump -d --no-show-raw-insn a.ifunc-noplt | FileCheck %s --check-prefixes=RELAX,NORELAX-MID
# RELAX-LABEL: <_start>:
diff --git a/lld/test/ELF/loongarch-relax-call36.s b/lld/test/ELF/loongarch-relax-call36.s
index 57ed214c9eb2ed..bda0c4f05da91c 100644
--- a/lld/test/ELF/loongarch-relax-call36.s
+++ b/lld/test/ELF/loongarch-relax-call36.s
@@ -4,12 +4,12 @@
# RUN: llvm-mc -filetype=obj -triple=loongarch64 -mattr=+relax a.s -o a.64.o
# RUN: llvm-mc -filetype=obj -triple=loongarch64 -mattr=+relax b.s -o b.64.o
-# RUN: ld.lld -shared -soname=b.so b.64.o -o b.64.so
-# RUN: ld.lld -T lds a.64.o b.64.so -o 64
+# RUN: ld.lld --relax -shared -soname=b.so b.64.o -o b.64.so
+# RUN: ld.lld --relax -T lds a.64.o b.64.so -o 64
# RUN: llvm-objdump -td --no-show-raw-insn 64 | FileCheck %s --check-prefix=RELAX
## --no-relax disables relaxation.
-# RUN: ld.lld -T lds a.64.o b.64.so --no-relax -o 64.norelax
+# RUN: ld.lld --no-relax -T lds a.64.o b.64.so -o 64.norelax
# RUN: llvm-objdump -td --no-show-raw-insn 64.norelax | FileCheck %s --check-prefix=NORELAX
# RELAX: {{0*}}00010000 g .text {{0*}}0000001c _start
diff --git a/lld/test/ELF/loongarch-relax-emit-relocs-2.s b/lld/test/ELF/loongarch-relax-emit-relocs-2.s
index 31cae939eca711..eddfc46b1ad086 100644
--- a/lld/test/ELF/loongarch-relax-emit-relocs-2.s
+++ b/lld/test/ELF/loongarch-relax-emit-relocs-2.s
@@ -3,15 +3,15 @@
## Call36 and tail36 need LA64 basic integer, so they donot have 32-bit version.
# RUN: llvm-mc --filetype=obj --triple=loongarch64 --mattr=+relax %s -o %t.64.o
-# RUN: ld.lld -Ttext=0x10000 --emit-relocs %t.64.o -o %t.64
+# RUN: ld.lld --relax -Ttext=0x10000 --emit-relocs %t.64.o -o %t.64
# RUN: llvm-objdump -dr %t.64 | FileCheck %s --check-prefix=RELAX
## -r should keep original relocations.
-# RUN: ld.lld -r %t.64.o -o %t.64.r
+# RUN: ld.lld --relax -r %t.64.o -o %t.64.r
# RUN: llvm-objdump -dr %t.64.r | FileCheck %s --check-prefix=CHECKR
## --no-relax should keep original relocations.
-# RUN: ld.lld -Ttext=0x10000 --emit-relocs --no-relax %t.64.o -o %t.64.norelax
+# RUN: ld.lld --no-relax -Ttext=0x10000 --emit-relocs %t.64.o -o %t.64.norelax
# RUN: llvm-objdump -dr %t.64.norelax | FileCheck %s --check-prefix=NORELAX
# RELAX: 00010000 <_start>:
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