[dsymutil] Add missing validation for zero alignment section

[Ch111p]

Section alignments in the DWARF segment are often zero by default. Therefore, the validation logic must be placed outside the alignUp path; otherwise, dsymutil may generate an invalid Mach-O file.

[llvmbot]

@llvm/pr-subscribers-debuginfo

Author: Ch1p (Ch111p)

Changes

Section alignments in the DWARF segment are often zero by default. Therefore, the validation logic must be placed outside the alignUp path; otherwise, dsymutil may generate an invalid Mach-O file.

---

Full diff: https://github.com/llvm/llvm-project/pull/168925.diff

1 Files Affected:

• (modified) llvm/tools/dsymutil/MachOUtils.cpp (+4-4)

diff --git a/llvm/tools/dsymutil/MachOUtils.cpp b/llvm/tools/dsymutil/MachOUtils.cpp
index 362a999515683..fba698896618b 100644
--- a/llvm/tools/dsymutil/MachOUtils.cpp
+++ b/llvm/tools/dsymutil/MachOUtils.cpp
@@ -339,11 +339,11 @@ static bool createDwarfSegment(const MCAssembler& Asm,uint64_t VMAddr, uint64_t
     if (Alignment > 1) {
       VMAddr = alignTo(VMAddr, Alignment);
       FileOffset = alignTo(FileOffset, Alignment);
-      if (FileOffset > UINT32_MAX)
-        return error("section " + Sec->getName() +
-                     "'s file offset exceeds 4GB."
-                     " Refusing to produce an invalid Mach-O file.");
     }
+    if (FileOffset > UINT32_MAX)
+      return error("section " + Sec->getName() +
+                   "'s file offset exceeds 4GB."
+                   " Refusing to produce an invalid Mach-O file.");
     Writer.writeSection(Asm, *Sec, VMAddr, FileOffset, 0, 0, 0);
 
     FileOffset += Asm.getSectionAddressSize(*Sec);

[JDevlieghere]

Good catch. LGTM.

[github-actions]

🐧 Linux x64 Test Results

• 186428 tests passed
• 4864 tests skipped

[Ch111p]

@JDevlieghere I don’t have the permissions to merge into the LLVM branch. Would you mind merging it on my behalf?

[llvm-ci]

LLVM Buildbot has detected a new failure on builder llvm-nvptx-nvidia-win running on as-builder-8 while building llvm at step 7 "test-build-unified-tree-check-llvm".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/54/builds/14905

Here is the relevant piece of the build log for the reference

Step 7 (test-build-unified-tree-check-llvm) failure: test (failure)
******************** TEST 'LLVM-Unit :: Support/./SupportTests.exe/79/105' FAILED ********************
Script(shard):
--
GTEST_OUTPUT=json:C:\buildbot\as-builder-8\llvm-nvptx-nvidia-win\build\unittests\Support\.\SupportTests.exe-LLVM-Unit-17644-79-105.json GTEST_SHUFFLE=0 GTEST_TOTAL_SHARDS=105 GTEST_SHARD_INDEX=79 C:\buildbot\as-builder-8\llvm-nvptx-nvidia-win\build\unittests\Support\.\SupportTests.exe
--


Note: This is test shard 80 of 105.

[==========] Running 16 tests from 16 test suites.

[----------] Global test environment set-up.

[----------] 1 test from BinaryStreamTest

[ RUN      ] BinaryStreamTest.DropOperations

[       OK ] BinaryStreamTest.DropOperations (0 ms)

[----------] 1 test from BinaryStreamTest (0 ms total)



[----------] 1 test from CommandLineTest

[ RUN      ] CommandLineTest.TokenizeAndMarkEOLs

[       OK ] CommandLineTest.TokenizeAndMarkEOLs (0 ms)

[----------] 1 test from CommandLineTest (0 ms total)



[----------] 1 test from DataExtractorTest

[ RUN      ] DataExtractorTest.LEB128_error

[       OK ] DataExtractorTest.LEB128_error (0 ms)

[----------] 1 test from DataExtractorTest (0 ms total)



[----------] 1 test from Error

[ RUN      ] Error.ForwardToExpected

[       OK ] Error.ForwardToExpected (0 ms)

[----------] 1 test from Error (0 ms total)
...