[lld] 2cb3d28 - [lld/mac] Add some comments and asserts

[Nico Weber via llvm-commits]

Author: Nico Weber
Date: 2022-04-07T15:43:28-04:00
New Revision: 2cb3d28b173570c4b34c5ce85bc18713670d07e1

URL: https://github.com/llvm/llvm-project/commit/2cb3d28b173570c4b34c5ce85bc18713670d07e1
DIFF: https://github.com/llvm/llvm-project/commit/2cb3d28b173570c4b34c5ce85bc18713670d07e1.diff

LOG: [lld/mac] Add some comments and asserts

I was wondering if SymtabSection::emitStabs() should check
defined->includeInSymtab. Add asserts and comments explaining why that's not
necessary.

No behavior change.

Differential Revision: https://reviews.llvm.org/D123302

Added: 
    

Modified: 
    lld/MachO/SymbolTable.cpp
    lld/MachO/SyntheticSections.cpp

Removed: 
    


################################################################################
diff  --git a/lld/MachO/SymbolTable.cpp b/lld/MachO/SymbolTable.cpp
index 2b6fb77f08aa4..a3e32537dc4f8 100644
--- a/lld/MachO/SymbolTable.cpp
+++ b/lld/MachO/SymbolTable.cpp
@@ -230,8 +230,9 @@ Defined *SymbolTable::addSynthetic(StringRef name, InputSection *isec,
                                    uint64_t value, bool isPrivateExtern,
                                    bool includeInSymtab,
                                    bool referencedDynamically) {
+  assert(!isec || !isec->getFile()); // See makeSyntheticInputSection().
   Defined *s =
-      addDefined(name, nullptr, isec, value, /*size=*/0,
+      addDefined(name, /*file=*/nullptr, isec, value, /*size=*/0,
                  /*isWeakDef=*/false, isPrivateExtern,
                  /*isThumb=*/false, referencedDynamically,
                  /*noDeadStrip=*/false, /*isWeakDefCanBeHidden=*/false);

diff  --git a/lld/MachO/SyntheticSections.cpp b/lld/MachO/SyntheticSections.cpp
index fd6f5e432e9ab..8ed6f5c2d51c2 100644
--- a/lld/MachO/SyntheticSections.cpp
+++ b/lld/MachO/SyntheticSections.cpp
@@ -908,6 +908,11 @@ void SymtabSection::emitStabs() {
       ObjFile *file = dyn_cast_or_null<ObjFile>(isec->getFile());
       if (!file || !file->compileUnit)
         continue;
+
+      // All symbols that set includeInSymtab to false are synthetic symbols.
+      // Those have `file` set to nullptr and were already skipped due to that.
+      assert(defined->includeInSymtab);
+
       symbolsNeedingStabs.push_back(defined);
     }
   }