Index: ELF/LinkerScript.h
===================================================================
--- ELF/LinkerScript.h
+++ ELF/LinkerScript.h
@@ -53,6 +53,12 @@
   std::vector<StringRef> Expr;
 };
 
+// Linker scripts allow additional constraints to be put on ouput sections.
+// An output section will only be created if all of its input sections are read-only
+// or all of its input sections are read-write by using the keyword ONLY_IF_RO
+// and ONLY_IF_RW respectively.
+enum ConstraintKind { NoConstraint, ReadOnly, ReadWrite };
+
 struct OutputSectionCommand : BaseCommand {
   OutputSectionCommand(StringRef Name)
       : BaseCommand(OutputSectionKind), Name(Name) {}
@@ -61,6 +67,7 @@
   std::vector<std::unique_ptr<BaseCommand>> Commands;
   std::vector<StringRef> Phdrs;
   std::vector<uint8_t> Filler;
+  ConstraintKind Constraint = NoConstraint;
 };
 
 struct InputSectionDescription : BaseCommand {
Index: ELF/LinkerScript.cpp
===================================================================
--- ELF/LinkerScript.cpp
+++ ELF/LinkerScript.cpp
@@ -265,12 +265,23 @@
 
   // Add input section to output section. If there is no output section yet,
   // then create it and add to output section list.
-  auto AddInputSec = [&](InputSectionBase<ELFT> *C, StringRef Name) {
+  auto AddInputSec = [&](InputSectionBase<ELFT> *C, StringRef Name,
+                         ConstraintKind Constraint) {
     OutputSectionBase<ELFT> *Sec;
     bool IsNew;
     std::tie(Sec, IsNew) = Factory.create(C, Name);
     if (IsNew)
       Result.push_back(Sec);
+    if ((!(C->getSectionHdr()->sh_flags & SHF_WRITE)) &&
+         Constraint == ReadWrite) {
+      Sec->DiscardFromOutput = true;
+      return;
+    }
+    if ((C->getSectionHdr()->sh_flags & SHF_WRITE) &&
+         Constraint == ReadOnly) {
+      Sec->DiscardFromOutput = true;
+      return;
+    }
     Sec->addSection(C);
   };
 
@@ -296,7 +307,7 @@
             if (OutCmd->Name == "/DISCARD/")
               S->Live = false;
             else
-              AddInputSec(S, OutCmd->Name);
+              AddInputSec(S, OutCmd->Name, OutCmd->Constraint);
           }
         }
       }
@@ -308,11 +319,17 @@
     for (InputSectionBase<ELFT> *S : F->getSections()) {
       if (!isDiscarded(S)) {
         if (!S->OutSec)
-          AddInputSec(S, getOutputSectionName(S));
+          AddInputSec(S, getOutputSectionName(S), NoConstraint);
       } else
         reportDiscarded(S, F);
     }
 
+  // Remove from the output all the sections which did not met the constraints.
+  Result.erase(std::remove_if(Result.begin(), Result.end(),
+                              [](OutputSectionBase<ELFT> *Sec) {
+                                return Sec->DiscardFromOutput;
+                              }),
+               Result.end());
   return Result;
 }
 
@@ -793,10 +810,17 @@
   OutputSectionCommand *Cmd = new OutputSectionCommand(OutSec);
   Opt.Commands.emplace_back(Cmd);
   expect(":");
+
+  // Parse constraints.
+  StringRef Tok = peek();
+  if (skip("ONLY_IF_RO"))
+    Cmd->Constraint = ReadOnly;
+  if (skip("ONLY_IF_RW"))
+    Cmd->Constraint = ReadWrite;
   expect("{");
 
   while (!Error && !skip("}")) {
-    StringRef Tok = next();
+    Tok = next();
     if (Tok == "*") {
       auto *InCmd = new InputSectionDescription();
       Cmd->Commands.emplace_back(InCmd);
@@ -820,7 +844,7 @@
   }
   Cmd->Phdrs = readOutputSectionPhdrs();
 
-  StringRef Tok = peek();
+  Tok = peek();
   if (Tok.startswith("=")) {
     if (!Tok.startswith("=0x")) {
       setError("filler should be a hexadecimal value");
Index: ELF/OutputSections.h
===================================================================
--- ELF/OutputSections.h
+++ ELF/OutputSections.h
@@ -78,6 +78,9 @@
   // Typically the first section of each PT_LOAD segment has this flag.
   bool PageAlign = false;
 
+  // If true, this section will be not included in the final binary.
+  bool DiscardFromOutput = false;
+
   virtual void finalize() {}
   virtual void finalizePieces() {}
   virtual void assignOffsets() {}
Index: test/ELF/linkerscript-sections-constraint.s
===================================================================
--- test/ELF/linkerscript-sections-constraint.s
+++ test/ELF/linkerscript-sections-constraint.s
@@ -8,9 +8,9 @@
 # RUN:   FileCheck -check-prefix=BASE %s
 # BASE: Sections:
 # BASE-NEXT: Idx Name          Size      Address          Type
-# BASE-NEXT:   0               00000000 0000000000000000 
-# BASE-NEXT:   1 .writable     00000004 0000000000000190 DATA 
-# BASE-NEXT:   2 .readable     00000004 0000000000000194 DATA 
+# BASE-NEXT:   0               00000000 0000000000000000
+# BASE-NEXT:   1 .writable     00000004 0000000000000190 DATA
+# BASE-NEXT:   2 .readable     00000004 0000000000000194 DATA
 
 # RUN: echo "SECTIONS { \
 # RUN:  .writable : ONLY_IF_RO { *(.writable) } \