[MachO] Move type size asserts to source files. NFC

As discussed in https://reviews.llvm.org/D113809#3128636. It's a bit
unfortunate to move the asserts away from the structs whose sizes
they're checking, but it's a far better developer experience when one of
the asserts is violated, because you get a single error instead of every
single source file including the header erroring out.

lld/MachO/InputSection.cpp

@@ -26,6 +26,11 @@ using namespace llvm::support;
 using namespace lld;
 using namespace lld::macho;
 
+// Verify ConcatInputSection's size on 64-bit builds.
+static_assert(sizeof(void *) != 8 || sizeof(ConcatInputSection) == 120,
+              "Try to minimize ConcatInputSection's size, we create many "
+              "instances of it");
+
 std::vector<ConcatInputSection *> macho::inputSections;
 
 uint64_t InputSection::getFileSize() const {

lld/MachO/InputSection.h

@@ -149,11 +149,6 @@ public:
   uint64_t outSecOff = 0;
 };
 
-// Verify ConcatInputSection's size on 64-bit builds.
-static_assert(sizeof(void *) != 8 || sizeof(ConcatInputSection) == 120,
-              "Try to minimize ConcatInputSection's size, we create many "
-              "instances of it");
-
 // Helper functions to make it easy to sprinkle asserts.
 
 inline bool shouldOmitFromOutput(InputSection *isec) {

lld/MachO/Relocations.cpp

@@ -17,6 +17,9 @@ using namespace llvm;
 using namespace lld;
 using namespace lld::macho;
 
+static_assert(sizeof(void *) != 8 || sizeof(Reloc) == 24,
+              "Try to minimize Reloc's size; we create many instances");
+
 bool macho::validateSymbolRelocation(const Symbol *sym,
                                      const InputSection *isec, const Reloc &r) {
   const RelocAttrs &relocAttrs = target->getRelocAttrs(r.type);

lld/MachO/Relocations.h

@@ -63,9 +63,6 @@ struct Reloc {
   llvm::PointerUnion<Symbol *, InputSection *> referent = nullptr;
 };
 
-static_assert(sizeof(void *) != 8 || sizeof(Reloc) == 24,
-              "Try to minimize Reloc's size; we create many instances");
-
 bool validateSymbolRelocation(const Symbol *, const InputSection *,
                               const Reloc &);
 

lld/MachO/Symbols.cpp

@@ -14,6 +14,19 @@ using namespace llvm;
 using namespace lld;
 using namespace lld::macho;
 
+static_assert(sizeof(void *) != 8 || sizeof(Symbol) == 48,
+              "Try to minimize Symbol's size; we create many instances");
+
+// The Microsoft ABI doesn't support using parent class tail padding for child
+// members, hence the _MSC_VER check.
+#if !defined(_MSC_VER)
+static_assert(sizeof(void *) != 8 || sizeof(Defined) == 80,
+              "Try to minimize Defined's size; we create many instances");
+#endif
+
+static_assert(sizeof(SymbolUnion) == sizeof(Defined),
+              "Defined should be the largest Symbol kind");
+
 // Returns a symbol for an error message.
 static std::string demangle(StringRef symName) {
   if (config->demangle)

lld/MachO/Symbols.h

@@ -109,9 +109,6 @@ public:
   bool used : 1;
 };
 
-static_assert(sizeof(void *) != 8 || sizeof(Symbol) == 48,
-              "Try to minimize Symbol's size; we create many instances");
-
 class Defined : public Symbol {
 public:
   Defined(StringRefZ name, InputFile *file, InputSection *isec, uint64_t value,
@@ -174,13 +171,6 @@ public:
   ConcatInputSection *compactUnwind = nullptr;
 };
 
-// The Microsoft ABI doesn't support using parent class tail padding for child
-// members, hence the _MSC_VER check.
-#if !defined(_MSC_VER)
-static_assert(sizeof(void *) != 8 || sizeof(Defined) == 80,
-              "Try to minimize Defined's size; we create many instances");
-#endif
-
 // This enum does double-duty: as a symbol property, it indicates whether & how
 // a dylib symbol is referenced. As a DylibFile property, it indicates the kind
 // of referenced symbols contained within the file. If there are both weak
@@ -307,9 +297,6 @@ union SymbolUnion {
   alignas(LazySymbol) char e[sizeof(LazySymbol)];
 };
 
-static_assert(sizeof(SymbolUnion) == sizeof(Defined),
-              "Defined should be the largest Symbol kind");
-
 template <typename T, typename... ArgT>
 T *replaceSymbol(Symbol *s, ArgT &&...arg) {
   static_assert(sizeof(T) <= sizeof(SymbolUnion), "SymbolUnion too small");