[Object] Change Archive::child_iterator for better interop with Error/Expected.

See http://reviews.llvm.org/D22079

Changes the Archive::child_begin and Archive::children to require a reference
to an Error. If iterator increment fails (because the archive header is
damaged) the iterator will be set to 'end()', and the error stored in the
given Error&. The Error value should be checked by the user immediately after
the loop. E.g.:

Error Err;
for (auto &C : A->children(Err)) {
  // Do something with archive child C.
}
// Check the error immediately after the loop.
if (Err)
  return Err;

Failure to check the Error will result in an abort() when the Error goes out of
scope (as guaranteed by the Error class).

llvm-svn: 275316

1 files changed, 24 insertions, 30 deletions

diff --git a/llvm/tools/llvm-size/llvm-size.cpp b/llvm/tools/llvm-size/llvm-size.cpp
index ecc0a0eac3c..c5966ead4b6 100644
--- a/llvm/tools/llvm-size/llvm-size.cpp
+++ b/llvm/tools/llvm-size/llvm-size.cpp
@@ -527,15 +527,12 @@ static void printFileSectionSizes(StringRef file) {
 
   if (Archive *a = dyn_cast<Archive>(&Bin)) {
     // This is an archive. Iterate over each member and display its sizes.
-    for (object::Archive::child_iterator i = a->child_begin(),
-                                         e = a->child_end();
-         i != e; ++i) {
-      if (error(i->getError()))
-        exit(1);
-      Expected<std::unique_ptr<Binary>> ChildOrErr = i->get().getAsBinary();
+    Error Err;
+    for (auto &C : a->children(Err)) {
+      Expected<std::unique_ptr<Binary>> ChildOrErr = C.getAsBinary();
       if (!ChildOrErr) {
         if (auto E = isNotObjectErrorInvalidFileType(ChildOrErr.takeError()))
-          error(std::move(E), a->getFileName(), i->get());
+          error(std::move(E), a->getFileName(), C);
         continue;
       }
       if (ObjectFile *o = dyn_cast<ObjectFile>(&*ChildOrErr.get())) {
@@ -555,6 +552,8 @@ static void printFileSectionSizes(StringRef file) {
         }
       }
     }
+    if (Err)
+      error(std::move(Err), a->getFileName());
   } else if (MachOUniversalBinary *UB =
                  dyn_cast<MachOUniversalBinary>(&Bin)) {
     // If we have a list of architecture flags specified dump only those.
@@ -597,17 +596,13 @@ static void printFileSectionSizes(StringRef file) {
               std::unique_ptr<Archive> &UA = *AOrErr;
               // This is an archive. Iterate over each member and display its
               // sizes.
-              for (object::Archive::child_iterator i = UA->child_begin(),
-                                                   e = UA->child_end();
-                   i != e; ++i) {
-                if (error(i->getError()))
-                  exit(1);
-                Expected<std::unique_ptr<Binary>> ChildOrErr =
-                                                  i->get().getAsBinary();
+              Error Err;
+              for (auto &C : UA->children(Err)) {
+                Expected<std::unique_ptr<Binary>> ChildOrErr = C.getAsBinary();
                 if (!ChildOrErr) {
                   if (auto E = isNotObjectErrorInvalidFileType(
                                     ChildOrErr.takeError()))
-                    error(std::move(E), UA->getFileName(), i->get(),
+                    error(std::move(E), UA->getFileName(), C,
                           ArchFlags.size() > 1 ?
                           StringRef(I->getArchTypeName()) : StringRef());
                   continue;
@@ -637,6 +632,8 @@ static void printFileSectionSizes(StringRef file) {
                   }
                 }
               }
+              if (Err)
+                error(std::move(Err), UA->getFileName());
             } else {
               consumeError(AOrErr.takeError());
               error("Mach-O universal file: " + file + " for architecture " +
@@ -688,17 +685,13 @@ static void printFileSectionSizes(StringRef file) {
             std::unique_ptr<Archive> &UA = *AOrErr;
             // This is an archive. Iterate over each member and display its
             // sizes.
-            for (object::Archive::child_iterator i = UA->child_begin(),
-                                                 e = UA->child_end();
-                 i != e; ++i) {
-              if (error(i->getError()))
-                exit(1);
-              Expected<std::unique_ptr<Binary>> ChildOrErr =
-                                                i->get().getAsBinary();
+            Error Err;
+            for (auto &C : UA->children(Err)) {
+              Expected<std::unique_ptr<Binary>> ChildOrErr = C.getAsBinary();
               if (!ChildOrErr) {
                 if (auto E = isNotObjectErrorInvalidFileType(
                                 ChildOrErr.takeError()))
-                  error(std::move(E), UA->getFileName(), i->get());
+                  error(std::move(E), UA->getFileName(), C);
                 continue;
               }
               if (ObjectFile *o = dyn_cast<ObjectFile>(&*ChildOrErr.get())) {
@@ -721,6 +714,8 @@ static void printFileSectionSizes(StringRef file) {
                 }
               }
             }
+            if (Err)
+              error(std::move(Err), UA->getFileName());
           } else {
             consumeError(AOrErr.takeError());
             error("Mach-O universal file: " + file + " for architecture " +
@@ -765,16 +760,13 @@ static void printFileSectionSizes(StringRef file) {
                          I->getAsArchive()) {
         std::unique_ptr<Archive> &UA = *AOrErr;
         // This is an archive. Iterate over each member and display its sizes.
-        for (object::Archive::child_iterator i = UA->child_begin(),
-                                             e = UA->child_end();
-             i != e; ++i) {
-          if (error(i->getError()))
-            exit(1);
-          Expected<std::unique_ptr<Binary>> ChildOrErr = i->get().getAsBinary();
+        Error Err;
+        for (auto &C : UA->children(Err)) {
+          Expected<std::unique_ptr<Binary>> ChildOrErr = C.getAsBinary();
           if (!ChildOrErr) {
             if (auto E = isNotObjectErrorInvalidFileType(
                               ChildOrErr.takeError()))
-              error(std::move(E), UA->getFileName(), i->get(), MoreThanOneArch ?
+              error(std::move(E), UA->getFileName(), C, MoreThanOneArch ?
                     StringRef(I->getArchTypeName()) : StringRef());
             continue;
           }
@@ -798,6 +790,8 @@ static void printFileSectionSizes(StringRef file) {
             }
           }
         }
+        if (Err)
+          error(std::move(Err), UA->getFileName());
       } else {
         consumeError(AOrErr.takeError());
         error("Mach-O universal file: " + file + " for architecture " +