[lld] wasm-ld: Implement function pointer alignment (PR #105532)

[Fangrui Song via llvm-commits]

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@@ -563,8 +563,24 @@ void ElemSection::addEntry(FunctionSymbol *sym) {
   // They only exist so that the calls to missing functions can validate.
   if (sym->hasTableIndex() || sym->isStub)
     return;
+
+  uint32_t padding = 0;
+  uint64_t alignment = 1;
+
+  if (indirectFunctions.size() == 0 && padding > 0) {
+    for (uint32_t i=0; i<padding; i++) {
+      indirectFunctions.push_back(nullptr);
+    }
+  }
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MaskRay wrote:

llvm/include/llvm/Support/MathExtras.h has ` constexpr T alignTo(U Value, V Align, W Skew)`, which might help here

https://github.com/llvm/llvm-project/pull/105532