[lld] [llvm] [lld] Fix -ObjC load behavior with LTO for section names with whitespace (PR #146654)
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Wed Jul 2 01:49:07 PDT 2025
https://github.com/aleksandr-urakov created https://github.com/llvm/llvm-project/pull/146654
This is a fix additional to #92162
In some cases, section names contain a whitespace between the segment name and the actual section name (e.g. `__TEXT, __swift5_proto`). It is confirmed by source code of the Swift compiler
This fix allows LTO to work correctly with the `-ObjC` flag in that rare case when only a section with a whitespace in the name is present in the linked bitcode module, but there are no sections containing `__TEXT,__swift`
>From d74d59eee050873da76ec674acae15ca6e300cb3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=D0=A3=D1=80=D0=B0=D0=BA=D0=BE=D0=B2=20=D0=90=D0=BB=D0=B5?=
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=?UTF-8?q?=D0=B5=D0=B5=D0=B2=D0=B8=D1=87?= <a.urakov at tbank.ru>
Date: Wed, 2 Jul 2025 11:32:28 +0300
Subject: [PATCH] [lld] Fix -ObjC load behavior with LTO for section names with
whitespace
This is a fix additional to #92162
In some cases, section names contain a whitespace between the segment name and
the actual section name (e.g. `__TEXT, __swift5_proto`). It is confirmed by
source code of the Swift compiler
This fix allows LTO to work correctly with the `-ObjC` flag in that rare case
when only a section with a whitespace in the name is present in the linked
bitcode module, but there are no sections containing `__TEXT,__swift`
---
lld/test/MachO/objc.s | 20 +++++++++++++++-----
llvm/lib/Bitcode/Reader/BitcodeReader.cpp | 3 ++-
2 files changed, 17 insertions(+), 6 deletions(-)
diff --git a/lld/test/MachO/objc.s b/lld/test/MachO/objc.s
index dbb9f1df27571..c327b206290ab 100644
--- a/lld/test/MachO/objc.s
+++ b/lld/test/MachO/objc.s
@@ -7,12 +7,13 @@
# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin %t/has-swift.s -o %t/has-swift.o
# RUN: llvm-as %t/has-swift-ir-loaded.ll -o %t/has-swift-ir-loaded.o
# RUN: llvm-as %t/has-swift-ir-not-loaded.ll -o %t/has-swift-ir-not-loaded.o
+# RUN: llvm-as %t/has-swift-with-space-ir-loaded.ll -o %t/has-swift-with-space-ir-loaded.o
# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin %t/has-swift-proto.s -o %t/has-swift-proto.o
# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin %t/no-objc.s -o %t/no-objc.o
## Make sure we don't mis-parse a 32-bit file as 64-bit
# RUN: llvm-mc -filetype=obj -triple=armv7-apple-watchos %t/no-objc.s -o %t/wrong-arch.o
-# RUN: llvm-ar rcs %t/libHasSomeObjC.a %t/no-objc.o %t/has-objc-symbol.o %t/has-objc-category.o %t/has-swift.o %t/has-swift-proto.o %t/has-swift-ir-loaded.o %t/has-swift-ir-not-loaded.o %t/wrong-arch.o
-# RUN: llvm-ar rcs %t/libHasSomeObjC2.a %t/no-objc.o %t/has-objc-symbol-and-category.o %t/has-swift.o %t/has-swift-proto.o %t/has-swift-ir-loaded.o %t/has-swift-ir-not-loaded.o %t/wrong-arch.o
+# RUN: llvm-ar rcs %t/libHasSomeObjC.a %t/no-objc.o %t/has-objc-symbol.o %t/has-objc-category.o %t/has-swift.o %t/has-swift-proto.o %t/has-swift-ir-loaded.o %t/has-swift-ir-not-loaded.o %t/has-swift-with-space-ir-loaded.o %t/wrong-arch.o
+# RUN: llvm-ar rcs %t/libHasSomeObjC2.a %t/no-objc.o %t/has-objc-symbol-and-category.o %t/has-swift.o %t/has-swift-proto.o %t/has-swift-ir-loaded.o %t/has-swift-ir-not-loaded.o %t/has-swift-with-space-ir-loaded.o %t/wrong-arch.o
# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin %t/test.s -o %t/test.o
@@ -22,7 +23,7 @@
# RUN: %lld -lSystem %t/test.o -o %t/test -L%t -lHasSomeObjC2 -ObjC
# RUN: llvm-objdump --section-headers --syms %t/test | FileCheck %s --check-prefix=OBJC
-# RUN: %no-fatal-warnings-lld -lSystem %t/test.o -o %t/test --start-lib %t/no-objc.o %t/has-objc-symbol.o %t/has-objc-category.o %t/has-swift.o %t/has-swift-proto.o %t/has-swift-ir-loaded.o %t/has-swift-ir-not-loaded.o %t/wrong-arch.o --end-lib -ObjC 2>&1 \
+# RUN: %no-fatal-warnings-lld -lSystem %t/test.o -o %t/test --start-lib %t/no-objc.o %t/has-objc-symbol.o %t/has-objc-category.o %t/has-swift.o %t/has-swift-proto.o %t/has-swift-ir-loaded.o %t/has-swift-ir-not-loaded.o %t/has-swift-with-space-ir-loaded.o %t/wrong-arch.o --end-lib -ObjC 2>&1 \
# RUN: | FileCheck -check-prefix=WARNING %s
# RUN: llvm-objdump --section-headers --syms %t/test | FileCheck %s --check-prefix=OBJC
@@ -34,14 +35,16 @@
# OBJC-NEXT: 0 __text {{.*}} TEXT
# OBJC-NEXT: 1 __swift {{.*}} DATA
# OBJC-NEXT: 2 __swift5_fieldmd{{.*}} DATA
-# OBJC-NEXT: 3 __objc_catlist {{.*}} DATA
-# OBJC-NEXT: 4 has_objc_symbol {{.*}} DATA
+# OBJC-NEXT: 3 __swift5_proto {{.*}} DATA
+# OBJC-NEXT: 4 __objc_catlist {{.*}} DATA
+# OBJC-NEXT: 5 has_objc_symbol {{.*}} DATA
# OBJC-EMPTY:
# OBJC-NEXT: SYMBOL TABLE:
# OBJC-DAG: g O __TEXT,__swift _foo
# OBJC-DAG: g F __TEXT,__text _main
# OBJC-DAG: g F __TEXT,__text _OBJC_CLASS_$_MyObject
# OBJC-DAG: g O __TEXT,__swift5_fieldmd $s7somelib4Blah_pMF
+# OBJC-DAG: g O __TEXT,__swift5_proto _baz
# RUN: %lld -lSystem %t/test.o -o %t/test -L%t -lHasSomeObjC
# RUN: llvm-objdump --section-headers --syms %t/test | FileCheck %s --check-prefix=NO-OBJC
@@ -117,6 +120,13 @@ target triple = "x86_64-apple-darwin"
@bar = global i64 1234
@llvm.used = appending global [1 x ptr] [ptr @bar]
+#--- has-swift-with-space-ir-loaded.ll
+target datalayout = "e-m:o-i64:64-i128:128-n32:64-S128"
+target triple = "x86_64-apple-darwin"
+
+ at baz = global i64 1234, section "__TEXT, __swift5_proto"
+ at llvm.used = appending global [1 x ptr] [ptr @baz]
+
#--- has-swift-proto.s
.section __TEXT,__swift5_fieldmd
.globl $s7somelib4Blah_pMF
diff --git a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
index de7bf9b7f4d79..7cc5fb39b4169 100644
--- a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -296,7 +296,8 @@ static Expected<bool> hasObjCCategoryInModule(BitstreamCursor &Stream) {
// Check for the i386 and other (x86_64, ARM) conventions
if (S.find("__DATA,__objc_catlist") != std::string::npos ||
S.find("__OBJC,__category") != std::string::npos ||
- S.find("__TEXT,__swift") != std::string::npos)
+ S.find("__TEXT,__swift") != std::string::npos ||
+ S.find("__TEXT, __swift") != std::string::npos)
return true;
break;
}
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