[PATCH] D14140: [ELF2] SECTIONS command basic support

[Denis Protivensky via llvm-commits]

denis-protivensky added a comment.

In http://reviews.llvm.org/D14140#282350, @rafael wrote:

> It is not clear if this is needed by real program. For now just leave
>  it out to have a simpler code. Even if it is needed, it would be
>  better to just organize the code as
>
> - add sections from input files
> - sort
> - add linker generated sections
> - sort the end + merge
>
>   no?


I'll leave simpler code, thanks.


================
Comment at: ELF/Writer.cpp:550-557
@@ -515,8 +549,10 @@
   // we can correctly decide if a dynamic relocation is needed.
-  for (const std::unique_ptr<ObjectFile<ELFT>> &F : Symtab.getObjectFiles())
-    for (InputSectionBase<ELFT> *B : F->getSections())
-      if (auto *S = dyn_cast_or_null<InputSection<ELFT>>(B))
-        if (S != &InputSection<ELFT>::Discarded)
-          if (S->isLive())
-            scanRelocs(*S);
+  for (const std::unique_ptr<ObjectFile<ELFT>> &F : Symtab.getObjectFiles()) {
+    for (InputSectionBase<ELFT> *C : F->getSections()) {
+      if (isDiscarded(C))
+        continue;
+      if (auto *S = dyn_cast<InputSection<ELFT>>(C))
+        scanRelocs(*S);
+    }
+  }
 
----------------
ruiu wrote:
>   for (const std::unique_ptr<ObjectFile<ELFT>> &F : Symtab.getObjectFiles())
>     for (InputSectionBase<ELFT> *C : F->getSections())
>       if (!isDiscarded(C))
>         if (auto *S = dyn_cast<InputSection<ELFT>>(C))
>           scanRelocs(*S);
Ok.

================
Comment at: ELF/Writer.cpp:906-911
@@ -869,1 +905,8 @@
 
+template <class ELFT> void Writer<ELFT>::parseSectionDescriptions() {
+  for (const std::pair<StringRef, OutputSectionDescription> &OutSec :
+       Config->OutputSections)
+    for (StringRef Name : OutSec.second.InputSectionNames)
+      InputToOutputSection[Name] = OutSec.second.Name;
+}
+
----------------
ruiu wrote:
> Looks like OutputSectionDescription doesn't have to be a struct. We can make Config->OutputSections of type StringMap<StringRef> which maps input section names to output section names.
I can't substitute MapVector with StringMap since I need to know original ordering of output sections defined in linker script so I can sort them accordingly.
I'll remove the OutputSectionDescription structure and use MapVector<StringRef, std::vector<StringRef>> instead.


http://reviews.llvm.org/D14140