[lld] Fix -ObjC load behavior with LTO for section names with whitespace

[aleksandr-urakov]

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

[github-actions]

Thank you for submitting a Pull Request (PR) to the LLVM Project!

This PR will be automatically labeled and the relevant teams will be notified.

If you wish to, you can add reviewers by using the "Reviewers" section on this page.

If this is not working for you, it is probably because you do not have write permissions for the repository. In which case you can instead tag reviewers by name in a comment by using @ followed by their GitHub username.

If you have received no comments on your PR for a week, you can request a review by "ping"ing the PR by adding a comment “Ping”. The common courtesy "ping" rate is once a week. Please remember that you are asking for valuable time from other developers.

If you have further questions, they may be answered by the LLVM GitHub User Guide.

You can also ask questions in a comment on this PR, on the LLVM Discord or on the forums.

[llvmbot]

@llvm/pr-subscribers-lld-macho

@llvm/pr-subscribers-lld

Author: None (aleksandr-urakov)

Changes

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

---

Full diff: https://github.com/llvm/llvm-project/pull/146654.diff

2 Files Affected:

• (modified) lld/test/MachO/objc.s (+15-5)
• (modified) llvm/lib/Bitcode/Reader/BitcodeReader.cpp (+2-1)

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"
+
+@baz = global i64 1234, section "__TEXT, __swift5_proto"
+@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;
     }