Index: ELF/LinkerScript.cpp
===================================================================
--- ELF/LinkerScript.cpp
+++ ELF/LinkerScript.cpp
@@ -406,15 +406,8 @@
       }
 
       // Add input sections to an output section.
-      unsigned Pos = 0;
-      for (InputSectionBase *S : V) {
-        // The actual offset will be computed during
-        // assignAddresses. For now, use the index as a very crude
-        // approximation so that it is at least easy for other code to
-        // know the section order.
-        cast<InputSection>(S)->OutSecOff = Pos++;
+      for (InputSectionBase *S : V)
         Factory.addInputSec(S, Cmd->Name, Cmd->Sec);
-      }
     }
   }
   CurOutSec = nullptr;
@@ -642,6 +635,11 @@
     Dot = CurMemRegion->Offset;
   switchTo(Sec);
 
+  // We do not support custom layout for compressed debug sectons.
+  // At this point we already know their size and have compressed content.
+  if (CurOutSec->Flags & SHF_COMPRESSED)
+    return;
+
   for (BaseCommand *C : Cmd->Commands)
     process(*C);
 }
Index: ELF/OutputSections.cpp
===================================================================
--- ELF/OutputSections.cpp
+++ ELF/OutputSections.cpp
@@ -139,12 +139,24 @@
   this->Info = S->OutSec->SectionIndex;
 }
 
+static uint64_t updateOffset(uint64_t Off, InputSection *S) {
+  Off = alignTo(Off, S->Alignment);
+  S->OutSecOff = Off;
+  return Off + S->getSize();
+}
+
 void OutputSection::addSection(InputSection *S) {
   assert(S->Live);
   Sections.push_back(S);
   S->OutSec = this;
   this->updateAlignment(S->Alignment);
 
+  // The actual offsets will be computed during assignAddresses. For now, use
+  // crude approximation so that it is at least easy for other code to know the
+  // section order. It is also to for calculate the output section size early
+  // for compressed debug sections.
+  this->Size = updateOffset(Size, S);
+
   // If this section contains a table of fixed-size entries, sh_entsize
   // holds the element size. Consequently, if this contains two or more
   // input sections, all of them must have the same sh_entsize. However,
@@ -159,11 +171,8 @@
 // and scan relocations to setup sections' offsets.
 void OutputSection::assignOffsets() {
   uint64_t Off = 0;
-  for (InputSection *S : Sections) {
-    Off = alignTo(Off, S->Alignment);
-    S->OutSecOff = Off;
-    Off += S->getSize();
-  }
+  for (InputSection *S : Sections)
+    Off = updateOffset(Off, S);
   this->Size = Off;
 }
 
Index: test/ELF/linkerscript/Inputs/compress-debug-sections.s
===================================================================
--- test/ELF/linkerscript/Inputs/compress-debug-sections.s
+++ test/ELF/linkerscript/Inputs/compress-debug-sections.s
@@ -0,0 +1,20 @@
+.section .debug_str,"MS",@progbits,1
+.Linfo_string0:
+  .asciz "CCC"
+.Linfo_string1:
+  .asciz "DDD"
+
+.section .debug_gnu_pubtypes,"",@progbits
+.long .LpubTypes_end0-.LpubTypes_begin0 # Length of Public Types Info
+.LpubTypes_begin0:
+ .short 2                      # DWARF Version
+ .long 0                       # Offset of Compilation Unit Info
+ .long 36                      # Compilation Unit Length
+ .long 36                      # DIE offset
+ .byte 144                     # Kind: TYPE, STATIC
+ .asciz "ccc"                  # External Name
+ .long 36                      # DIE offset
+ .byte 144                     # Kind: TYPE, STATIC
+ .asciz "ddd"                  # External Name
+ .long 0                       # End Mark
+.LpubTypes_end0:
Index: test/ELF/linkerscript/compress-debug-sections.s
===================================================================
--- test/ELF/linkerscript/compress-debug-sections.s
+++ test/ELF/linkerscript/compress-debug-sections.s
@@ -0,0 +1,49 @@
+# REQUIRES: x86, zlib
+
+# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux \
+# RUN:   %S/Inputs/compress-debug-sections.s -o %t1.o
+# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t2.o
+# RUN: echo "SECTIONS { }" > %t.script
+# RUN: ld.lld %t1.o %t2.o %t.script -o %t --compress-debug-sections=zlib
+# RUN: llvm-dwarfdump %t | FileCheck %s
+
+# RUN: echo "SECTIONS { .debug_str 0 : { *(.debug_str) } \
+# RUN:                  .debug_gnu_pubtypes 0 : { *(.debug_gnu_pubtypes) } }" > %t2.script
+# RUN: ld.lld %t1.o %t2.o %t2.script -o %t2 --compress-debug-sections=zlib
+# RUN: llvm-dwarfdump %t2 | FileCheck %s
+
+# CHECK:       .debug_str contents:
+# CHECK-NEXT:    CCC
+# CHECK-NEXT:    DDD
+# CHECK-NEXT:    AAA
+# CHECK-NEXT:    BBB
+# CHECK:      .debug_gnu_pubtypes contents:
+# CHECK-NEXT:   length = 0x00000020 version = 0x0002 unit_offset = 0x00000000 unit_size = 0x00000024
+# CHECK-NEXT:   Offset     Linkage  Kind     Name
+# CHECK-NEXT:   0x00000024 STATIC   TYPE     "ccc"
+# CHECK-NEXT:   0x00000024 STATIC   TYPE     "ddd"
+# CHECK-NEXT:   length = 0x00000020 version = 0x0002 unit_offset = 0x00000000 unit_size = 0x00000024
+# CHECK-NEXT:   Offset     Linkage  Kind     Name
+# CHECK-NEXT:   0x00000024 STATIC   TYPE     "aaa"
+# CHECK-NEXT:   0x00000024 STATIC   TYPE     "bbb"
+
+.section .debug_str,"MS",@progbits,1
+.Linfo_string0:
+  .asciz "AAA"
+.Linfo_string1:
+  .asciz "BBB"
+   
+.section .debug_gnu_pubtypes,"",@progbits
+.long .LpubTypes_end0-.LpubTypes_begin0 # Length of Public Types Info
+.LpubTypes_begin0:
+ .short 2                      # DWARF Version
+ .long 0                       # Offset of Compilation Unit Info
+ .long 36                      # Compilation Unit Length
+ .long 36                      # DIE offset
+ .byte 144                     # Kind: TYPE, STATIC
+ .asciz "aaa"                  # External Name
+ .long 36                      # DIE offset
+ .byte 144                     # Kind: TYPE, STATIC
+ .asciz "bbb"                  # External Name
+ .long 0                       # End Mark
+.LpubTypes_end0: