[llvm] [llvm-objcopy] Add --change-section-address (PR #98664)

[James Henderson via llvm-commits]

================
@@ -745,6 +745,52 @@ static Error handleArgs(const CommonConfig &Config, const ELFConfig &ELFConfig,
     }
   }
 
+  if (!Config.ChangeSectionAddress.empty()) {
+    if (Obj.isRelocatable()) {
+      StringMap<AddressUpdate> SectionsToUpdateAddress;
+      for (const SectionPatternAddressUpdate &PatternUpdate :
+           make_range(Config.ChangeSectionAddress.rbegin(),
+                      Config.ChangeSectionAddress.rend())) {
+        for (SectionBase &Sec : Obj.sections()) {
+          if (PatternUpdate.SectionPattern.matches(Sec.Name)) {
+            if (SectionsToUpdateAddress
+                    .try_emplace(Sec.Name, PatternUpdate.Update)
+                    .second) {
+              if (PatternUpdate.Update.Absolute) {
+                Sec.Addr = PatternUpdate.Update.Value;
+              } else if (PatternUpdate.Update.Negative &&
+                         Sec.Addr < PatternUpdate.Update.Value) {
+                return createStringError(
+                    errc::invalid_argument,
+                    "address 0x" + Twine::utohexstr(Sec.Addr) +
+                        " cannot be decreased by 0x" +
+                        Twine::utohexstr(PatternUpdate.Update.Value) +
+                        ". The result would underflow");
+              } else if (!PatternUpdate.Update.Negative &&
----------------
jh7370 wrote:

Reorganise these into:
```
if (CaseThatTriggersAnError) {
  return error
}
if (OtherCaseThatTriggersAnError) {
  return error
}
...Remaining code...
```

https://github.com/llvm/llvm-project/pull/98664