[ELF][test] Improve test coverage

lld/test/ELF/common-page.s

@@ -221,3 +221,8 @@ _start:
 # CHECK-COMMON-NEXT:       PF_W (0x2)
 # CHECK-COMMON-NEXT:     ]
 # CHECK-COMMON-NEXT:     Alignment: 0
+
+# RUN: not ld.lld -z max-page-size=0x10001 -z common-page-size=0x1001 %t -o /dev/null 2>&1 | FileCheck %s --check-prefix=INVALID
+
+# INVALID:      error: max-page-size: value isn't a power of 2
+# INVALID-NEXT: error: common-page-size: value isn't a power of 2

lld/test/ELF/linkerscript/memory-err.s

@@ -35,6 +35,9 @@
 # RUN: not ld.lld -o /dev/null -T %t.script %t.o 2>&1 | FileCheck --check-prefix=ERR5 %s
 # ERR5: error: memory region 'ram' not declared
 
+# RUN: echo 'SECTIONS { .text : { *(.text) } AT> ram }' > %t.script
+# RUN: not ld.lld -o /dev/null -T %t.script %t.o 2>&1 | FileCheck --check-prefix=ERR5 %s
+
 ## Check region overflow.
 
 # RUN: echo 'MEMORY { ram (rwx) : ORIGIN = 0, LENGTH = 2K } \

lld/test/ELF/start-group.s

@@ -0,0 +1,13 @@
+# REQUIRES: x86
+
+# RUN: llvm-mc -filetype=obj -triple=x86_64 %s -o %t.o
+
+# RUN: not ld.lld --start-group --start-group %t.o 2>&1 | FileCheck %s --check-prefix=NESTED
+# NESTED: nested --start-group
+
+# RUN: not ld.lld --end-group 2>&1 | FileCheck %s --check-prefix=END
+# RUN: not ld.lld '-)' 2>&1 | FileCheck %s --check-prefix=END
+# END: stray --end-group
+
+.globl _start
+_start:

lld/test/ELF/warn-backrefs.s

@@ -31,6 +31,7 @@
 # RUN: echo 'GROUP("%t2.a" "%t1.o")' > %t2.lds
 # RUN: ld.lld --fatal-warnings --warn-backrefs %t2.lds -o /dev/null
 # RUN: ld.lld --fatal-warnings --warn-backrefs '-(' %t2.a %t1.o '-)' -o /dev/null
+# RUN: ld.lld --fatal-warnings --warn-backrefs --start-group %t2.a %t1.o --end-group -o /dev/null
 
 ## A backward reference from %t1.o to %t2.a (added by %t3.lds).
 # RUN: echo 'GROUP("%t2.a")' > %t3.lds