Index: llvm/test/tools/obj2yaml/dynamic-section.test
===================================================================
--- llvm/test/tools/obj2yaml/dynamic-section.test
+++ llvm/test/tools/obj2yaml/dynamic-section.test
@@ -1,10 +1,10 @@
-# RUN: yaml2obj %s -o %t
-# RUN: obj2yaml %t | FileCheck %s
-
 ## Check we can use obj2yaml to yamalize the object containing
 ## .dynamic section. Check that resulting section has the
 ## proper attributes and dynamic tags.
 
+# RUN: yaml2obj -DENTSIZE=0x10 %s -o %t1
+# RUN: obj2yaml %t1 | FileCheck %s
+
 # CHECK:       Sections:
 # CHECK-NEXT:  - Name:            .dynamic
 # CHECK-NEXT:    Type:            SHT_DYNAMIC
@@ -136,7 +136,7 @@
     Type:            SHT_DYNAMIC
     Address:         0x0000000000001000
     AddressAlign:    0x0000000000002000
-    EntSize:         0x0000000000000010
+    EntSize:         [[ENTSIZE]]
     Entries:
       - Tag:             DT_NULL
         Value:           0x0000000000000000
@@ -250,3 +250,11 @@
         Value:           0x0000000000000036
       - Tag:             DT_USED
         Value:           0x0000000000000001
+
+## Document the current behavior when sh_entsize is invalid.
+## Here we use 0xFE as an arbitrary broken value instead of expected 0x16.
+
+# RUN: yaml2obj -DENTSIZE=0xff %s -o %t2
+# RUN: not obj2yaml %t2 2>&1 | FileCheck %s --check-prefix=ENTSIZE
+
+# ENTSIZE: section [index 1] has an invalid sh_entsize: 255
Index: llvm/test/tools/obj2yaml/rel-rela-section.yaml
===================================================================
--- llvm/test/tools/obj2yaml/rel-rela-section.yaml
+++ llvm/test/tools/obj2yaml/rel-rela-section.yaml
@@ -31,3 +31,24 @@
 DynamicSymbols:
   - Name:    bar
     Binding: STB_GLOBAL
+
+## Document the behavior when the sh_entsize field is broken.
+## Here we use the 0xFE value instead of expected 0x18/0x10.
+
+# RUN: yaml2obj -DTYPE=SHT_RELA --docnum=2 %s -o %t2.rela
+# RUN: not obj2yaml %t2.rela 2>&1 | FileCheck %s --check-prefix=ERR
+# RUN: yaml2obj -DTYPE=SHT_REL  --docnum=2 %s -o %t2.rel
+# RUN: not obj2yaml %t2.rel 2>&1 | FileCheck %s --check-prefix=ERR
+
+# ERR: section [index 1] has an invalid sh_entsize: 254
+
+--- !ELF
+FileHeader:
+  Class:   ELFCLASS64
+  Data:    ELFDATA2LSB
+  Type:    ET_DYN
+  Machine: EM_X86_64
+Sections:
+  - Name:    .foo
+    Type:    [[TYPE]]
+    EntSize: 0xFE
Index: llvm/test/tools/obj2yaml/relr-section.yaml
===================================================================
--- llvm/test/tools/obj2yaml/relr-section.yaml
+++ llvm/test/tools/obj2yaml/relr-section.yaml
@@ -1,69 +1,93 @@
-## Test how we dump SHT_RELR sections for 32 and 64-bit targets.
-
-## Test we use the "Entries" property when it is possible do
-## dump values correctly.
-
-# RUN: yaml2obj --docnum=1 -D BITS=32 -D ENCODE=LSB %s -o %t.32le
-# RUN: obj2yaml %t.32le | FileCheck %s --check-prefix=ELF32LE
-# RUN: yaml2obj --docnum=1 -D BITS=32 -D ENCODE=MSB %s -o %t.32be
-# RUN: obj2yaml %t.32be | FileCheck %s --check-prefix=ELF32BE
-# RUN: yaml2obj --docnum=1 -D BITS=64 -D ENCODE=LSB %s -o %t.64le
-# RUN: obj2yaml %t.64le | FileCheck %s --check-prefix=ELF64LE
-# RUN: yaml2obj --docnum=1 -D BITS=64 -D ENCODE=MSB %s -o %t.64be
-# RUN: obj2yaml %t.64be | FileCheck %s --check-prefix=ELF64BE
-
-# ELF64LE:      Sections:
-# ELF64LE-NEXT:   - Name:    .relr.dyn
-# ELF64LE-NEXT:     Type:    SHT_RELR
-# ELF64LE-NEXT:     EntSize: 0x0000000000000008
-# ELF64LE-NEXT:     Entries: [ 0x8877665544332211 ]
-
-# ELF32LE:      Sections:
-# ELF32LE-NEXT:   - Name:    .relr.dyn
-# ELF32LE-NEXT:     Type:    SHT_RELR
-# ELF32LE-NEXT:     EntSize: 0x0000000000000004
-# ELF32LE-NEXT:     Entries: [ 0x0000000044332211, 0x0000000088776655 ]
-
-# ELF64BE:      Sections:
-# ELF64BE-NEXT:   - Name:    .relr.dyn
-# ELF64BE-NEXT:     Type:    SHT_RELR
-# ELF64BE-NEXT:     EntSize: 0x0000000000000008
-# ELF64BE-NEXT:     Entries: [ 0x1122334455667788 ]
-
-# ELF32BE:      Sections:
-# ELF32BE-NEXT:  - Name:    .relr.dyn
-# ELF32BE-NEXT:    Type:    SHT_RELR
-# ELF32BE-NEXT:    EntSize: 0x0000000000000004
-# ELF32BE-NEXT:    Entries: [ 0x0000000011223344, 0x0000000055667788 ]
-
---- !ELF
-FileHeader:
-  Class:   ELFCLASS[[BITS]]
-  Data:    ELFDATA2[[ENCODE]]
-  Type:    ET_DYN
-  Machine: EM_X86_64
-Sections:
-  - Name: .relr.dyn
-    Type: SHT_RELR
-    Content: "1122334455667788"
-
-## Test we use the "Content" property when a SHT_RELR section is truncated.
-
-# RUN: yaml2obj --docnum=2 %s -o %t.content
-# RUN: obj2yaml %t.content | FileCheck %s --check-prefix=CONTENT
-
-# CONTENT:      - Name:    .relr.dyn
-# CONTENT-NEXT:   Type:    SHT_RELR
-# CONTENT-NEXT:   EntSize: 0x0000000000000008
-# CONTENT-NEXT:   Content: '11223344556677'
-
---- !ELF
-FileHeader:
-  Class:   ELFCLASS64
-  Data:    ELFDATA2MSB
-  Type:    ET_DYN
-  Machine: EM_X86_64
-Sections:
-  - Name: .relr.dyn
-    Type: SHT_RELR
-    Content: "11223344556677"
+## Test how we dump SHT_RELR sections for 32 and 64-bit targets.
+
+## Test we use the "Entries" property when it is possible do
+## dump values correctly.
+
+# RUN: yaml2obj --docnum=1 -D BITS=32 -D ENCODE=LSB %s -o %t.32le
+# RUN: obj2yaml %t.32le | FileCheck %s --check-prefix=ELF32LE
+# RUN: yaml2obj --docnum=1 -D BITS=32 -D ENCODE=MSB %s -o %t.32be
+# RUN: obj2yaml %t.32be | FileCheck %s --check-prefix=ELF32BE
+# RUN: yaml2obj --docnum=1 -D BITS=64 -D ENCODE=LSB %s -o %t.64le
+# RUN: obj2yaml %t.64le | FileCheck %s --check-prefix=ELF64LE
+# RUN: yaml2obj --docnum=1 -D BITS=64 -D ENCODE=MSB %s -o %t.64be
+# RUN: obj2yaml %t.64be | FileCheck %s --check-prefix=ELF64BE
+
+# ELF64LE:      Sections:
+# ELF64LE-NEXT:   - Name:    .relr.dyn
+# ELF64LE-NEXT:     Type:    SHT_RELR
+# ELF64LE-NEXT:     EntSize: 0x0000000000000008
+# ELF64LE-NEXT:     Entries: [ 0x8877665544332211 ]
+
+# ELF32LE:      Sections:
+# ELF32LE-NEXT:   - Name:    .relr.dyn
+# ELF32LE-NEXT:     Type:    SHT_RELR
+# ELF32LE-NEXT:     EntSize: 0x0000000000000004
+# ELF32LE-NEXT:     Entries: [ 0x0000000044332211, 0x0000000088776655 ]
+
+# ELF64BE:      Sections:
+# ELF64BE-NEXT:   - Name:    .relr.dyn
+# ELF64BE-NEXT:     Type:    SHT_RELR
+# ELF64BE-NEXT:     EntSize: 0x0000000000000008
+# ELF64BE-NEXT:     Entries: [ 0x1122334455667788 ]
+
+# ELF32BE:      Sections:
+# ELF32BE-NEXT:  - Name:    .relr.dyn
+# ELF32BE-NEXT:    Type:    SHT_RELR
+# ELF32BE-NEXT:    EntSize: 0x0000000000000004
+# ELF32BE-NEXT:    Entries: [ 0x0000000011223344, 0x0000000055667788 ]
+
+--- !ELF
+FileHeader:
+  Class:   ELFCLASS[[BITS]]
+  Data:    ELFDATA2[[ENCODE]]
+  Type:    ET_DYN
+  Machine: EM_X86_64
+Sections:
+  - Name: .relr.dyn
+    Type: SHT_RELR
+    Content: "1122334455667788"
+
+## Test we use the "Content" property when a SHT_RELR section is truncated.
+
+# RUN: yaml2obj --docnum=2 %s -o %t.content
+# RUN: obj2yaml %t.content | FileCheck %s --check-prefix=CONTENT
+
+# CONTENT:      - Name:    .relr.dyn
+# CONTENT-NEXT:   Type:    SHT_RELR
+# CONTENT-NEXT:   EntSize: 0x0000000000000008
+# CONTENT-NEXT:   Content: '11223344556677'
+
+--- !ELF
+FileHeader:
+  Class:   ELFCLASS64
+  Data:    ELFDATA2MSB
+  Type:    ET_DYN
+  Machine: EM_X86_64
+Sections:
+  - Name: .relr.dyn
+    Type: SHT_RELR
+    Content: "11223344556677"
+
+## Test we are able to dump SHT_RELR section when sh_entsize is invalid.
+## Here we use 0xFE as a value instead of expected 0x8.
+
+# RUN: yaml2obj --docnum=3 %s -o %t.entsize
+# RUN: obj2yaml %t.entsize | FileCheck %s --check-prefix=ENTSIZE
+
+# ENTSIZE:        - Name:    .relr.dyn
+# ENTSIZE-NEXT:     Type:    SHT_RELR
+# ENTSIZE-NEXT:     EntSize: 0x00000000000000FE
+# ENTSIZE-NEXT:     Content: '1122334455667788'
+# ENTSIZE-NEXT: ...
+
+--- !ELF
+FileHeader:
+  Class:   ELFCLASS64
+  Data:    ELFDATA2MSB
+  Type:    ET_DYN
+  Machine: EM_X86_64
+Sections:
+  - Name:    .relr.dyn
+    Type:    SHT_RELR
+    EntSize: 0xFE
+    Content: "1122334455667788"