[lld] a0f0a69 - [lld][MachO] Fix symbol insertion in `transplantSymbolsAtOffset` (#120737)

[via llvm-commits]

Author: Carlo Cabrera
Date: 2024-12-22T21:50:15+08:00
New Revision: a0f0a69b625748b97e40195c8d81b3746d30f985

URL: https://github.com/llvm/llvm-project/commit/a0f0a69b625748b97e40195c8d81b3746d30f985
DIFF: https://github.com/llvm/llvm-project/commit/a0f0a69b625748b97e40195c8d81b3746d30f985.diff

LOG: [lld][MachO] Fix symbol insertion in `transplantSymbolsAtOffset` (#120737)

The existing comparison does not insert symbols in the intended place.

Closes #120559.

---------

Co-authored-by: Bjorn Pettersson <bjorn.a.pettersson at ericsson.com>

Added: 
    

Modified: 
    lld/MachO/SymbolTable.cpp

Removed: 
    


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diff  --git a/lld/MachO/SymbolTable.cpp b/lld/MachO/SymbolTable.cpp
index f0a92da8777e13..a61e60a944fb45 100644
--- a/lld/MachO/SymbolTable.cpp
+++ b/lld/MachO/SymbolTable.cpp
@@ -67,10 +67,15 @@ static void transplantSymbolsAtOffset(InputSection *fromIsec,
                                       InputSection *toIsec, Defined *skip,
                                       uint64_t fromOff, uint64_t toOff) {
   // Ensure the symbols will still be in address order after our insertions.
-  auto insertIt = llvm::upper_bound(toIsec->symbols, toOff,
-                                    [](uint64_t off, const Symbol *s) {
-                                      return cast<Defined>(s)->value < off;
-                                    });
+  auto symSucceedsOff = [](uint64_t off, const Symbol *s) {
+    return cast<Defined>(s)->value > off;
+  };
+  assert(std::is_partitioned(toIsec->symbols.begin(), toIsec->symbols.end(),
+                             [symSucceedsOff, toOff](const Symbol *s) {
+                               return !symSucceedsOff(toOff, s);
+                             }) &&
+         "Symbols in toIsec must be partitioned by toOff.");
+  auto insertIt = llvm::upper_bound(toIsec->symbols, toOff, symSucceedsOff);
   llvm::erase_if(fromIsec->symbols, [&](Symbol *s) {
     auto *d = cast<Defined>(s);
     if (d->value != fromOff)