Index: ELF/LinkerScript.cpp
===================================================================
--- ELF/LinkerScript.cpp
+++ ELF/LinkerScript.cpp
@@ -897,6 +897,18 @@
     expect(")");
     return [](uint64_t Dot) { return alignTo(Dot, Target->PageSize); };
   }
+  if (Tok == "ASSERT") {
+    expect("(");
+    Expr E = readExpr();
+    expect(",");
+    StringRef Msg = next();
+    expect(")");
+    return [=](uint64_t Dot) {
+      if (!E(Dot))
+        error(Msg);
+      return Dot;
+    };
+  }
 
   // Parse a symbol name or a number literal.
   uint64_t V = 0;
Index: test/ELF/linkerscript/linkerscript-assert.s
===================================================================
--- test/ELF/linkerscript/linkerscript-assert.s
+++ test/ELF/linkerscript/linkerscript-assert.s
@@ -0,0 +1,58 @@
+# REQUIRES: x86
+# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t1.o
+
+# RUN: echo "SECTIONS { \
+# RUN:  .aaa         : { *(.aaa) } \
+# RUN:  _end_aaa = .; \
+# RUN:  . = ASSERT(_end_aaa == 0x128, \"Assert fail!\"); \
+# RUN:  .bbb         : { *(.bbb) } \
+# RUN:  _end_bbb = .; \
+# RUN:  . = ASSERT(_end_bbb <= 0x128 * 2, \"Assert fail!\"); \
+# RUN:  }" > %t1.script
+# RUN: ld.lld -o %t1 --script %t1.script %t1.o
+# RUN: llvm-readobj -s %t1 | FileCheck %s -check-prefix=PASS
+# PASS:      Section {
+# PASS:        Index: 2
+# PASS-NEXT:   Name: .bbb
+# PASS-NEXT:   Type: SHT_PROGBITS
+# PASS-NEXT:   Flags [
+# PASS-NEXT:     SHF_ALLOC
+# PASS-NEXT:   ]
+# PASS-NEXT:   Address: 0x128
+# PASS-NEXT:   Offset: 0x128
+# PASS-NEXT:   Size: 8
+# PASS-NEXT:   Link:
+# PASS-NEXT:   Info:
+# PASS-NEXT:   AddressAlignment:
+# PASS-NEXT:   EntrySize:
+# PASS-NEXT: }
+
+# RUN: echo "SECTIONS { \
+# RUN:  .aaa         : { *(.aaa) } \
+# RUN:  _end_aaa = .; \
+# RUN:  . = ASSERT(_end_aaa != 0x128, \"Assert fail!\"); \
+# RUN:  }" > %t2.script
+# RUN: not ld.lld -o %t2 --script %t2.script %t1.o > %t.log 2>&1
+# RUN: FileCheck %s -check-prefix=FAIL < %t.log
+# FAIL: Assert fail!
+
+# RUN: echo "SECTIONS { \
+# RUN:  .aaa         : { *(.aaa) } \
+# RUN:  _end_aaa = .; \
+# RUN:  . = ASSERT(_end_aaa == 0x128, \"Assert fail!\"); \
+# RUN:  .bbb         : { *(.bbb) } \
+# RUN:  _end_bbb = .; \
+# RUN:  . = ASSERT(_end_bbb > 0x128 * 2, \"Assert fail!\"); \
+# RUN:  }" > %t3.script
+# RUN: not ld.lld -o %t3 --script %t3.script %t1.o > %t.log 2>&1
+# RUN: FileCheck %s -check-prefix=FAIL < %t.log
+
+.global _start
+_start:
+ nop
+
+.section .aaa,"a"
+ .quad 0
+
+.section .bbb,"a"
+ .quad 0