[LLD] [ELF] Add support for linker script unary plus operator

[partaror]

This commit adds support for linker script unary plus ('+') operator. It is helpful for improving compatibility between LLD and GNU LD.

Closes #118047

[llvmbot]

@llvm/pr-subscribers-lld-elf

@llvm/pr-subscribers-lld

Author: Parth Arora (partaror)

Changes

This commit adds support for linker script unary plus ('+') operator. It is helpful for improving compatibility between LLD and GNU LD.

---

Full diff: https://github.com/llvm/llvm-project/pull/121508.diff

2 Files Affected:

• (modified) lld/ELF/ScriptParser.cpp (+3)
• (modified) lld/test/ELF/linkerscript/operators.test (+2)

diff --git a/lld/ELF/ScriptParser.cpp b/lld/ELF/ScriptParser.cpp
index f53515cc3f3c0d..49ddd5e7999cfd 100644
--- a/lld/ELF/ScriptParser.cpp
+++ b/lld/ELF/ScriptParser.cpp
@@ -1489,6 +1489,9 @@ Expr ScriptParser::readPrimary() {
     Expr e = readPrimary();
     return [=] { return -e().getValue(); };
   }
+  if (consume("+")) {
+    return readPrimary();
+  }
 
   StringRef tok = next();
   std::string location = getCurrentLocation();
diff --git a/lld/test/ELF/linkerscript/operators.test b/lld/test/ELF/linkerscript/operators.test
index 27209a2e40f598..d7b3becf36d706 100644
--- a/lld/test/ELF/linkerscript/operators.test
+++ b/lld/test/ELF/linkerscript/operators.test
@@ -73,6 +73,7 @@ SECTIONS {
   log2ceil100000000 = LOG2CEIL(0x100000000);
   log2ceil100000001 = LOG2CEIL(0x100000001);
   log2ceilmax = LOG2CEIL(0xffffffffffffffff);
+  unaryadd = +3 + ++5;
 }
 
 # CHECK:      0000000000000002 A unary
@@ -126,6 +127,7 @@ SECTIONS {
 # CHECK-NEXT: 0000000000000020 A log2ceil100000000
 # CHECK-NEXT: 0000000000000021 A log2ceil100000001
 # CHECK-NEXT: 0000000000000040 A log2ceilmax
+# CHECK-NEXT: 0000000000000008 A unaryadd
 
 ## Mailformed number error.
 # RUN: echo "SECTIONS { . = 0x12Q41; }" > %t.script

[lenary]

LGTM

[MaskRay]

> Fixes 118047

I'd prefer "Close" since this is a new minor feature instead of a bugfix.

[partaror]

I'd prefer "Close" since this is a new minor feature instead of a bugfix.

Agreed. I have replaced Fixes with Closes in both the PR description and the commit message.

[partaror]

Gentle ping for review @smithp35

[smithp35]

Apologies, I didn't think you were waiting on me. I think an approval from MaskRay is sufficient.

LGTM too.

[partaror]

@MaskRay Can you please let me know if it is okay if I merge the pull-request myself?

[MaskRay]

LGTM