[PATCH] D138135: [lld][ELF] Support LoongArch

[Jinyang He via Phabricator via llvm-commits]

MQ-mengqing added a comment.





================
Comment at: lld/ELF/InputSection.cpp:653
+    // duplicate some logic here.
+    if (sym.isTls()) {
+      if (sym.hasFlag(NEEDS_TLSGD))
----------------
xen0n wrote:
> MQ-mengqing wrote:
> > xen0n wrote:
> > > MQ-mengqing wrote:
> > > > How about the "la.tls.ie" and "la.tls.gd" do the same symbol?
> > > > How about the "la.tls.ie" and "la.tls.gd" do the same symbol?
> > > 
> > > What do you mean by "do the same symbol" here? Maybe you can tell me in a bit of Chinese if it's easier to explain that way... for now honestly I can't understand. (If you do attach some Chinese phrase I'll take care of translating it.)
> > Sorry for the ambiguity words. I just care about the follows things,
> > ```
> > la.tls.ie $r4, y
> > la.tls.gd $r5, y
> > 
> > .section .tbss
> > .globl y
> > y:
> > .word   0
> > .size   y, 4
> > ```
> > It plays differently with gnu as-ld.
> I've located the TLS IE offset logic in the BFD code (IE symbol = offset by 2 GOT entries) and tried to do the same in LLD, but unfortunately the output was broken so I have to revert most of it. Sadly I won't have enough time to investigate before end of year.
Ping for not getting reply about here for a long time.

File: test.s
```
la.tls.ie $r4, y
la.tls.gd $r5, y

.section .tbss
.globl y
y:
.word   0
.size   y, 4
```

Pre-cmd: 
     $ llvm-mc -filetype=obj --triple=loongarch64 test.s -o test.o
     $ ld.lld test.o -shared -o test.lld
     $ ld test.o -shared -o test.ld

Compare1:
    $ readelf -Wr test.{ld, lld}
```
test.ld:
0000000000008008  0000000300000007 R_LARCH_TLS_DTPMOD64   0000000000000000 y + 0
0000000000008010  0000000300000009 R_LARCH_TLS_DTPREL64   0000000000000000 y + 0
0000000000008018  000000030000000b R_LARCH_TLS_TPREL64    0000000000000000 y + 0

test.lld:
0000000000020398  0000000100000002 R_LARCH_64             0000000000000000 y + 0
00000000000203a0  0000000100000007 R_LARCH_TLS_DTPMOD64   0000000000000000 y + 0
00000000000203a8  0000000100000009 R_LARCH_TLS_DTPREL64   0000000000000000 y + 0
00000000000203b0  000000010000000b R_LARCH_TLS_TPREL64    0000000000000000 y + 0
```
Compare2:
    $ objdump -d test.{ld, lld}
```
test.ld:
0000000000000250 <.text>:
 250:	1a000104 	pcalau12i   	$a0, 8(0x8)
 254:	28c06084 	ld.d        	$a0, $a0, 24(0x18)
 258:	1a000105 	pcalau12i   	$a1, 8(0x8)
 25c:	02c020a5 	addi.d      	$a1, $a1, 8(0x8)

test.lld:
00000000000102d0 <.text>:
   102d0:	1a000204 	pcalau12i   	$a0, 16(0x10)
   102d4:	28ce8084 	ld.d        	$a0, $a0, 928(0x3a0)
   102d8:	1a000205 	pcalau12i   	$a1, 16(0x10)
   102dc:	02ce80a5 	addi.d      	$a1, $a1, 928(0x3a0)
```


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D138135/new/

https://reviews.llvm.org/D138135