diff --git a/lld/MachO/Arch/X86_64.cpp b/lld/MachO/Arch/X86_64.cpp
--- a/lld/MachO/Arch/X86_64.cpp
+++ b/lld/MachO/Arch/X86_64.cpp
@@ -6,6 +6,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "InputFiles.h"
 #include "Symbols.h"
 #include "SyntheticSections.h"
 #include "Target.h"
@@ -25,7 +26,8 @@
   X86_64();
 
   uint64_t getImplicitAddend(const uint8_t *loc, uint8_t type) const override;
-  void relocateOne(uint8_t *loc, uint8_t type, uint64_t val) const override;
+  void relocateOne(const InputSection &, const Reloc &, uint8_t *loc,
+                   uint64_t val) const override;
 
   void writeStub(uint8_t *buf, const DylibSymbol &) const override;
   void writeStubHelperHeader(uint8_t *buf) const override;
@@ -55,19 +57,47 @@
   }
 }
 
-void X86_64::relocateOne(uint8_t *loc, uint8_t type, uint64_t val) const {
-  switch (type) {
+// Slow! Do not call in any hot path (all error message generation should be on
+// cold paths anyway.)
+static std::string getErrorLocation(const InputSection &isec,
+                                    const Reloc &rel) {
+  InputFile *file = isec.file;
+  std::string prefix =
+      "invalid type " + std::to_string(rel.type) + " relocation at offset ";
+
+  for (const SubsectionMap &subsectionMap : file->subsections) {
+    for (auto &p : subsectionMap) {
+      uint32_t subsecOff = p.first;
+      const InputSection *subsection = p.second;
+      if (subsection == &isec)
+        return (prefix + std::to_string(subsecOff + rel.offset) + " of " +
+                isec.segname + "," + isec.name + " in " + file->getName())
+            .str();
+    }
+  }
+  llvm_unreachable("could not find input section");
+}
+
+void X86_64::relocateOne(const InputSection &isec, const Reloc &rel,
+                         uint8_t *loc, uint64_t val) const {
+  switch (rel.type) {
   case X86_64_RELOC_BRANCH:
   case X86_64_RELOC_SIGNED:
   case X86_64_RELOC_SIGNED_1:
   case X86_64_RELOC_SIGNED_2:
   case X86_64_RELOC_SIGNED_4:
   case X86_64_RELOC_GOT_LOAD:
+    if (!rel.pcrel)
+      fatal(getErrorLocation(isec, rel) + ": type " + std::to_string(rel.type) +
+            " relocations must be pcrel");
     // These types are only used for pc-relative relocations, so offset by 4
     // since the RIP has advanced by 4 at this point.
     write32le(loc, val - 4);
     break;
   case X86_64_RELOC_UNSIGNED:
+    if (rel.pcrel)
+      fatal(getErrorLocation(isec, rel) + ": type " + std::to_string(rel.type) +
+            " relocations must not be pcrel");
     write64le(loc, val);
     break;
   default:
diff --git a/lld/MachO/InputSection.cpp b/lld/MachO/InputSection.cpp
--- a/lld/MachO/InputSection.cpp
+++ b/lld/MachO/InputSection.cpp
@@ -46,6 +46,6 @@
     uint64_t val = va + addend;
     if (r.pcrel)
       val -= getVA() + r.offset;
-    target->relocateOne(buf + r.offset, r.type, val);
+    target->relocateOne(*this, r, buf + r.offset, val);
   }
 }
diff --git a/lld/MachO/Target.h b/lld/MachO/Target.h
--- a/lld/MachO/Target.h
+++ b/lld/MachO/Target.h
@@ -16,6 +16,8 @@
 namespace macho {
 
 class DylibSymbol;
+class InputSection;
+struct Reloc;
 
 enum {
   // We are currently only supporting 64-bit targets since macOS and iOS are
@@ -32,7 +34,8 @@
 
   virtual uint64_t getImplicitAddend(const uint8_t *loc,
                                      uint8_t type) const = 0;
-  virtual void relocateOne(uint8_t *loc, uint8_t type, uint64_t val) const = 0;
+  virtual void relocateOne(const InputSection &, const Reloc &, uint8_t *loc,
+                           uint64_t val) const = 0;
 
   // Write code for lazy binding. See the comments on StubsSection for more
   // details.
diff --git a/lld/test/MachO/invalid/invalid-relocation.yaml b/lld/test/MachO/invalid/invalid-relocation.yaml
new file mode 100644
--- /dev/null
+++ b/lld/test/MachO/invalid/invalid-relocation.yaml
@@ -0,0 +1,99 @@
+# REQUIRES: x86
+# RUN: yaml2obj %s -o %t.o
+# RUN: not lld -flavor darwinnew -o %t %t.o 2>&1 | FileCheck %s -DFILE=%t.o
+#
+# CHECK: error: invalid type 0 relocation at offset 1 of __TEXT,__text in [[FILE]]: type 0 relocations must not be pcrel
+
+!mach-o
+FileHeader:
+  magic:           0xFEEDFACF
+  cputype:         0x01000007
+  cpusubtype:      0x00000003
+  filetype:        0x00000001
+  ncmds:           4
+  sizeofcmds:      280
+  flags:           0x00000000
+  reserved:        0x00000000
+LoadCommands:
+  - cmd:             LC_SEGMENT_64
+    cmdsize:         152
+    segname:         ''
+    vmaddr:          0
+    vmsize:          9
+    fileoff:         312
+    filesize:        9
+    maxprot:         7
+    initprot:        7
+    nsects:          1
+    flags:           0
+    Sections:
+      - sectname:        __text
+        segname:         __TEXT
+        addr:            0x0000000000000000
+        size:            9
+        offset:          0x00000138
+        align:           0
+        reloff:          0x00000144
+        nreloc:          1
+        flags:           0x80000000
+        reserved1:       0x00000000
+        reserved2:       0x00000000
+        reserved3:       0x00000000
+        content:         '000000000000000000'
+        relocations:
+          - address:         0x00000001
+            symbolnum:       1
+            pcrel:           true
+            length:          3
+            extern:          true
+            type:            0
+            scattered:       false
+            value:           0
+  - cmd:             LC_BUILD_VERSION
+    cmdsize:         24
+    platform:        1
+    minos:           659200
+    sdk:             0
+    ntools:          0
+  - cmd:             LC_SYMTAB
+    cmdsize:         24
+    symoff:          332
+    nsyms:           2
+    stroff:          364
+    strsize:         12
+  - cmd:             LC_DYSYMTAB
+    cmdsize:         80
+    ilocalsym:       0
+    nlocalsym:       0
+    iextdefsym:      0
+    nextdefsym:      2
+    iundefsym:       2
+    nundefsym:       0
+    tocoff:          0
+    ntoc:            0
+    modtaboff:       0
+    nmodtab:         0
+    extrefsymoff:    0
+    nextrefsyms:     0
+    indirectsymoff:  0
+    nindirectsyms:   0
+    extreloff:       0
+    nextrel:         0
+    locreloff:       0
+    nlocrel:         0
+LinkEditData:
+  NameList:
+    - n_strx:          1
+      n_type:          0x0F
+      n_sect:          1
+      n_desc:          0
+      n_value:         1
+    - n_strx:          6
+      n_type:          0x0F
+      n_sect:          1
+      n_desc:          0
+      n_value:         9
+  StringTable:
+    - ''
+    - _foo
+    - _main