diff --git a/llvm/utils/gn/secondary/llvm/lib/Target/WebAssembly/AsmParser/BUILD.gn b/llvm/utils/gn/secondary/llvm/lib/Target/WebAssembly/AsmParser/BUILD.gn
new file mode 100644
index 000000000000..158f9e97fd84
--- /dev/null
+++ b/llvm/utils/gn/secondary/llvm/lib/Target/WebAssembly/AsmParser/BUILD.gn
@@ -0,0 +1,23 @@
+import("//llvm/utils/TableGen/tablegen.gni")
+
+tablegen("WebAssemblyGenAsmMatcher") {
+  visibility = [ ":AsmParser" ]
+  args = [ "-gen-asm-matcher" ]
+  td_file = "../WebAssembly.td"
+}
+
+static_library("AsmParser") {
+  output_name = "LLVMWebAssemblyAsmParser"
+  deps = [
+    ":WebAssemblyGenAsmMatcher",
+    "//llvm/lib/MC",
+    "//llvm/lib/MC/MCParser",
+    "//llvm/lib/Support",
+    "//llvm/lib/Target/WebAssembly/MCTargetDesc",
+    "//llvm/lib/Target/WebAssembly/TargetInfo",
+  ]
+  include_dirs = [ ".." ]
+  sources = [
+    "WebAssemblyAsmParser.cpp",
+  ]
+}
diff --git a/llvm/utils/gn/secondary/llvm/lib/Target/WebAssembly/BUILD.gn b/llvm/utils/gn/secondary/llvm/lib/Target/WebAssembly/BUILD.gn
new file mode 100644
index 000000000000..58781a070ccf
--- /dev/null
+++ b/llvm/utils/gn/secondary/llvm/lib/Target/WebAssembly/BUILD.gn
@@ -0,0 +1,121 @@
+import("//llvm/utils/TableGen/tablegen.gni")
+
+tablegen("WebAssemblyGenCallingConv") {
+  visibility = [ ":LLVMWebAssemblyCodeGen" ]
+  args = [ "-gen-callingconv" ]
+  td_file = "WebAssembly.td"
+}
+
+tablegen("WebAssemblyGenDAGISel") {
+  visibility = [ ":LLVMWebAssemblyCodeGen" ]
+  args = [ "-gen-dag-isel" ]
+  td_file = "WebAssembly.td"
+}
+
+tablegen("WebAssemblyGenFastISel") {
+  visibility = [ ":LLVMWebAssemblyCodeGen" ]
+  args = [ "-gen-fast-isel" ]
+  td_file = "WebAssembly.td"
+}
+
+tablegen("WebAssemblyGenGlobalISel") {
+  visibility = [ ":LLVMWebAssemblyCodeGen" ]
+  args = [ "-gen-global-isel" ]
+  td_file = "WebAssembly.td"
+}
+
+tablegen("WebAssemblyGenMCPseudoLowering") {
+  visibility = [ ":LLVMWebAssemblyCodeGen" ]
+  args = [ "-gen-pseudo-lowering" ]
+  td_file = "WebAssembly.td"
+}
+
+tablegen("WebAssemblyGenRegisterBank") {
+  visibility = [ ":LLVMWebAssemblyCodeGen" ]
+  args = [ "-gen-register-bank" ]
+  td_file = "WebAssembly.td"
+}
+
+static_library("LLVMWebAssemblyCodeGen") {
+  deps = [
+    ":WebAssemblyGenCallingConv",
+    ":WebAssemblyGenDAGISel",
+    ":WebAssemblyGenFastISel",
+    ":WebAssemblyGenGlobalISel",
+    ":WebAssemblyGenMCPseudoLowering",
+    ":WebAssemblyGenRegisterBank",
+    "InstPrinter",
+    "MCTargetDesc",
+    "TargetInfo",
+    "//llvm/include/llvm/Config:llvm-config",
+    "//llvm/lib/Analysis",
+    "//llvm/lib/CodeGen",
+    "//llvm/lib/CodeGen/AsmPrinter",
+    "//llvm/lib/CodeGen/GlobalISel",
+    "//llvm/lib/CodeGen/SelectionDAG",
+    "//llvm/lib/IR",
+    "//llvm/lib/MC",
+    "//llvm/lib/Support",
+    "//llvm/lib/Target",
+  ]
+  include_dirs = [ "." ]
+  sources = [
+    "WebAssemblyAddMissingPrototypes.cpp",
+    "WebAssemblyArgumentMove.cpp",
+    "WebAssemblyAsmPrinter.cpp",
+    "WebAssemblyCFGSort.cpp",
+    "WebAssemblyCFGStackify.cpp",
+    "WebAssemblyCallIndirectFixup.cpp",
+    "WebAssemblyEHRestoreStackPointer.cpp",
+    "WebAssemblyExceptionInfo.cpp",
+    "WebAssemblyExplicitLocals.cpp",
+    "WebAssemblyFastISel.cpp",
+    "WebAssemblyFixFunctionBitcasts.cpp",
+    "WebAssemblyFixIrreducibleControlFlow.cpp",
+    "WebAssemblyFrameLowering.cpp",
+    "WebAssemblyISelDAGToDAG.cpp",
+    "WebAssemblyISelLowering.cpp",
+    "WebAssemblyInstrInfo.cpp",
+    "WebAssemblyLateEHPrepare.cpp",
+    "WebAssemblyLowerBrUnless.cpp",
+    "WebAssemblyLowerEmscriptenEHSjLj.cpp",
+    "WebAssemblyLowerGlobalDtors.cpp",
+    "WebAssemblyMCInstLower.cpp",
+    "WebAssemblyMachineFunctionInfo.cpp",
+    "WebAssemblyOptimizeLiveIntervals.cpp",
+    "WebAssemblyOptimizeReturned.cpp",
+    "WebAssemblyPeephole.cpp",
+    "WebAssemblyPrepareForLiveIntervals.cpp",
+    "WebAssemblyRegColoring.cpp",
+    "WebAssemblyRegNumbering.cpp",
+    "WebAssemblyRegStackify.cpp",
+    "WebAssemblyRegisterInfo.cpp",
+    "WebAssemblyReplacePhysRegs.cpp",
+    "WebAssemblyRuntimeLibcallSignatures.cpp",
+    "WebAssemblySelectionDAGInfo.cpp",
+    "WebAssemblySetP2AlignOperands.cpp",
+    "WebAssemblyStoreResults.cpp",
+    "WebAssemblySubtarget.cpp",
+    "WebAssemblyTargetMachine.cpp",
+    "WebAssemblyTargetObjectFile.cpp",
+    "WebAssemblyTargetTransformInfo.cpp",
+    "WebAssemblyUtilities.cpp",
+  ]
+}
+
+# This is a bit different from most build files: Due to this group
+# having the directory's name, "//llvm/lib/Target/AArch64" will refer to this
+# target, which pulls in the code in this directory *and all subdirectories*.
+# For most other directories, "//llvm/lib/Foo" only pulls in the code directly
+# in "llvm/lib/Foo". The forwarding targets in //llvm/lib/Target expect this
+# different behavior.
+group("WebAssembly") {
+  deps = [
+    ":LLVMWebAssemblyCodeGen",
+    "AsmParser",
+    "Disassembler",
+    "InstPrinter",
+    "MCTargetDesc",
+    "TargetInfo",
+  ]
+}
diff --git a/llvm/utils/gn/secondary/llvm/lib/Target/WebAssembly/Disassembler/BUILD.gn b/llvm/utils/gn/secondary/llvm/lib/Target/WebAssembly/Disassembler/BUILD.gn
new file mode 100644
index 000000000000..44e586dbdd79
--- /dev/null
+++ b/llvm/utils/gn/secondary/llvm/lib/Target/WebAssembly/Disassembler/BUILD.gn
@@ -0,0 +1,23 @@
+import("//llvm/utils/TableGen/tablegen.gni")
+
+tablegen("WebAssemblyGenDisassemblerTables") {
+  visibility = [ ":Disassembler" ]
+  args = [ "-gen-disassembler" ]
+  td_file = "../WebAssembly.td"
+}
+
+static_library("Disassembler") {
+  output_name = "LLVMWebAssemblyDisassembler"
+  deps = [
+    ":WebAssemblyGenDisassemblerTables",
+    "//llvm/lib/MC",
+    "//llvm/lib/MC/MCDisassembler",
+    "//llvm/lib/Support",
+    "//llvm/lib/Target/WebAssembly/MCTargetDesc",
+    "//llvm/lib/Target/WebAssembly/TargetInfo",
+  ]
+  include_dirs = [ ".." ]
+  sources = [
+    "WebAssemblyDisassembler.cpp",
+  ]
+}
diff --git a/llvm/utils/gn/secondary/llvm/lib/Target/WebAssembly/InstPrinter/BUILD.gn b/llvm/utils/gn/secondary/llvm/lib/Target/WebAssembly/InstPrinter/BUILD.gn
new file mode 100644
index 000000000000..e63ea79174e9
--- /dev/null
+++ b/llvm/utils/gn/secondary/llvm/lib/Target/WebAssembly/InstPrinter/BUILD.gn
@@ -0,0 +1,24 @@
+import("//llvm/utils/TableGen/tablegen.gni")
+
+tablegen("WebAssemblyGenAsmWriter") {
+  visibility = [ ":InstPrinter" ]
+  args = [ "-gen-asm-writer" ]
+  td_file = "../WebAssembly.td"
+}
+
+static_library("InstPrinter") {
+  output_name = "LLVMWebAssemblyAsmPrinter"
+  deps = [
+    ":WebAssemblyGenAsmWriter",
+    "//llvm/lib/MC",
+    "//llvm/lib/Support",
+
+    # MCTargetDesc depends on InstPrinter, so we can't depend on the full
+    # MCTargetDesc target here: it would form a cycle.
+    "//llvm/lib/Target/WebAssembly/MCTargetDesc:tablegen",
+  ]
+  include_dirs = [ ".." ]
+  sources = [
+    "WebAssemblyInstPrinter.cpp",
+  ]
+}
diff --git a/llvm/utils/gn/secondary/llvm/lib/Target/WebAssembly/MCTargetDesc/BUILD.gn b/llvm/utils/gn/secondary/llvm/lib/Target/WebAssembly/MCTargetDesc/BUILD.gn
new file mode 100644
index 000000000000..8d8e6c0a0e90
--- /dev/null
+++ b/llvm/utils/gn/secondary/llvm/lib/Target/WebAssembly/MCTargetDesc/BUILD.gn
@@ -0,0 +1,61 @@
+import("//llvm/utils/TableGen/tablegen.gni")
+
+tablegen("WebAssemblyGenInstrInfo") {
+  visibility = [ ":tablegen" ]
+  args = [ "-gen-instr-info" ]
+  td_file = "../WebAssembly.td"
+}
+
+tablegen("WebAssemblyGenMCCodeEmitter") {
+  visibility = [ ":tablegen" ]
+  args = [ "-gen-emitter" ]
+  td_file = "../WebAssembly.td"
+}
+
+tablegen("WebAssemblyGenRegisterInfo") {
+  visibility = [ ":tablegen" ]
+  args = [ "-gen-register-info" ]
+  td_file = "../WebAssembly.td"
+}
+
+tablegen("WebAssemblyGenSubtargetInfo") {
+  visibility = [ ":tablegen" ]
+  args = [ "-gen-subtarget" ]
+  td_file = "../WebAssembly.td"
+}
+
+group("tablegen") {
+  visibility = [
+    ":MCTargetDesc",
+    "../InstPrinter",
+    "../TargetInfo",
+    "../Utils",
+  ]
+  public_deps = [
+    ":WebAssemblyGenInstrInfo",
+    ":WebAssemblyGenMCCodeEmitter",
+    ":WebAssemblyGenRegisterInfo",
+    ":WebAssemblyGenSubtargetInfo",
+  ]
+}
+static_library("MCTargetDesc") {
+  output_name = "LLVMWebAssemblyDesc"
+  public_deps = [
+    ":tablegen",
+  ]
+  deps = [
+    "//llvm/lib/MC",
+    "//llvm/lib/Support",
+    "//llvm/lib/Target/WebAssembly/InstPrinter",
+    "//llvm/lib/Target/WebAssembly/TargetInfo",
+  ]
+  include_dirs = [ ".." ]
+  sources = [
+    "WebAssemblyAsmBackend.cpp",
+    "WebAssemblyMCAsmInfo.cpp",
+    "WebAssemblyMCCodeEmitter.cpp",
+    "WebAssemblyMCTargetDesc.cpp",
+    "WebAssemblyTargetStreamer.cpp",
+    "WebAssemblyWasmObjectWriter.cpp",
+  ]
+}
diff --git a/llvm/utils/gn/secondary/llvm/lib/Target/WebAssembly/TargetInfo/BUILD.gn b/llvm/utils/gn/secondary/llvm/lib/Target/WebAssembly/TargetInfo/BUILD.gn
new file mode 100644
index 000000000000..334183bb5d6f
--- /dev/null
+++ b/llvm/utils/gn/secondary/llvm/lib/Target/WebAssembly/TargetInfo/BUILD.gn
@@ -0,0 +1,14 @@
+static_library("TargetInfo") {
+  output_name = "LLVMWebAssemblyInfo"
+  deps = [
+    "//llvm/lib/Support",
+
+    # MCTargetDesc depends on TargetInfo, so we can't depend on the full
+    # MCTargetDesc target here: it would form a cycle.
+    "//llvm/lib/Target/WebAssembly/MCTargetDesc:tablegen",
+  ]
+  include_dirs = [ ".." ]
+  sources = [
+    "WebAssemblyTargetInfo.cpp",
+  ]
+}
diff --git a/llvm/utils/gn/secondary/llvm/lib/Target/targets.gni b/llvm/utils/gn/secondary/llvm/lib/Target/targets.gni
index 01252d0c4d0f..5a01d7f758c4 100644
--- a/llvm/utils/gn/secondary/llvm/lib/Target/targets.gni
+++ b/llvm/utils/gn/secondary/llvm/lib/Target/targets.gni
@@ -20,6 +20,7 @@ if (llvm_targets_to_build == "host") {
   llvm_targets_to_build = [
     "AArch64",
     "ARM",
+    "WebAssembly",
     "X86",
   ]
 }
@@ -28,12 +29,15 @@ if (llvm_targets_to_build == "host") {
 # and remember which targets are built.
 llvm_build_AArch64 = false
 llvm_build_ARM = false
+llvm_build_WebAssembly = false
 llvm_build_X86 = false
 foreach(target, llvm_targets_to_build) {
   if (target == "AArch64") {
     llvm_build_AArch64 = true
   } else if (target == "ARM") {
     llvm_build_ARM = true
+  } else if (target == "WebAssembly") {
+    llvm_build_WebAssembly = true
   } else if (target == "X86") {
     llvm_build_X86 = true
   } else {
diff --git a/llvm/utils/gn/secondary/llvm/unittests/BUILD.gn b/llvm/utils/gn/secondary/llvm/unittests/BUILD.gn
index 89cb9b6724b3..de8e89ff4343 100644
--- a/llvm/utils/gn/secondary/llvm/unittests/BUILD.gn
+++ b/llvm/utils/gn/secondary/llvm/unittests/BUILD.gn
@@ -54,6 +54,9 @@ group("unittests") {
   if (llvm_build_ARM) {
     deps += [ "tools/llvm-exegesis/ARM:LLVMExegesisARMTests" ]
   }
+  if (llvm_build_WebAssembly) {
+    deps += [ "Target/WebAssembly:WebAssemblyTests" ]
+  }
   if (llvm_build_X86) {
     deps += [ "tools/llvm-exegesis/X86:LLVMExegesisX86Tests" ]
   }
diff --git a/llvm/utils/gn/secondary/llvm/unittests/Target/WebAssembly/BUILD.gn b/llvm/utils/gn/secondary/llvm/unittests/Target/WebAssembly/BUILD.gn
new file mode 100644
index 000000000000..e02149f738d6
--- /dev/null
+++ b/llvm/utils/gn/secondary/llvm/unittests/Target/WebAssembly/BUILD.gn
@@ -0,0 +1,18 @@
+import("//llvm/utils/unittest/unittest.gni")
+
+unittest("WebAssemblyTests") {
+  deps = [
+    "//llvm/lib/CodeGen",
+    "//llvm/lib/CodeGen/MIRParser",
+    "//llvm/lib/IR",
+    "//llvm/lib/MC",
+    "//llvm/lib/Support",
+    "//llvm/lib/Target/WebAssembly:LLVMWebAssemblyCodeGen",
+    "//llvm/lib/Target/WebAssembly/MCTargetDesc",
+    "//llvm/lib/Target/WebAssembly/TargetInfo",
+  ]
+  include_dirs = [ "//llvm/lib/Target/WebAssembly" ]
+  sources = [
+    "WebAssemblyExceptionInfoTest.cpp",
+  ]
+}