3 files changed, 45 insertions, 2 deletions

diff --git a/src/util/fipstools/delocate/delocate.go b/src/util/fipstools/delocate/delocate.go
index a43b4286..92b4c31d 100644
--- a/src/util/fipstools/delocate/delocate.go
+++ b/src/util/fipstools/delocate/delocate.go
@@ -803,6 +803,8 @@ const (
 	instrCombine
 	// instrThreeArg merges two sources into a destination in some fashion.
 	instrThreeArg
+	// instrCompare takes two arguments and writes outputs to the flags register.
+	instrCompare
 	instrOther
 )
 
@@ -833,6 +835,11 @@ func classifyInstruction(instr string, args []*node32) instructionType {
 			return instrCombine
 		}
 
+	case "cmpq":
+		if len(args) == 2 {
+			return instrCompare
+		}
+
 	case "sarxq", "shlxq", "shrxq":
 		if len(args) == 3 {
 			return instrThreeArg
@@ -855,6 +862,13 @@ func push(w stringWriter) wrapperFunc {
 	}
 }
 
+func compare(w stringWriter, instr, a, b string) wrapperFunc {
+	return func(k func()) {
+		k()
+		w.WriteString(fmt.Sprintf("\t%s %s, %s\n", instr, a, b))
+	}
+}
+
 func (d *delocation) loadFromGOT(w stringWriter, destination, symbol, section string, redzoneCleared bool) wrapperFunc {
 	d.gotExternalsNeeded[symbol+"@"+section] = struct{}{}
 
@@ -1074,7 +1088,7 @@ Args:
 				}
 
 				classification := classifyInstruction(instructionName, argNodes)
-				if classification != instrThreeArg && i != 0 {
+				if classification != instrThreeArg && classification != instrCompare && i != 0 {
 					return nil, errors.New("GOT access must be source operand")
 				}
 
@@ -1091,6 +1105,17 @@ Args:
 				case instrMove:
 					assertNodeType(argNodes[1], ruleRegisterOrConstant)
 					targetReg = d.contents(argNodes[1])
+				case instrCompare:
+					otherSource := d.contents(argNodes[i^1])
+					saveRegWrapper, tempReg := saveRegister(d.output, []string{otherSource})
+					redzoneCleared = true
+					wrappers = append(wrappers, saveRegWrapper)
+					if i == 0 {
+						wrappers = append(wrappers, compare(d.output, instructionName, tempReg, otherSource))
+					} else {
+						wrappers = append(wrappers, compare(d.output, instructionName, otherSource, tempReg))
+					}
+					targetReg = tempReg
 				case instrTransformingMove:
 					assertNodeType(argNodes[1], ruleRegisterOrConstant)
 					targetReg = d.contents(argNodes[1])
@@ -1114,7 +1139,7 @@ Args:
 						return nil, fmt.Errorf("three-argument instruction has %d arguments", n)
 					}
 					if i != 0 && i != 1 {
-						return nil, errors.New("GOT access must be from soure operand")
+						return nil, errors.New("GOT access must be from source operand")
 					}
 					targetReg = d.contents(argNodes[2])
 
diff --git a/src/util/fipstools/delocate/testdata/x86_64-GOTRewrite/in.s b/src/util/fipstools/delocate/testdata/x86_64-GOTRewrite/in.s
index ccbc0bf3..398032f8 100644
--- a/src/util/fipstools/delocate/testdata/x86_64-GOTRewrite/in.s
+++ b/src/util/fipstools/delocate/testdata/x86_64-GOTRewrite/in.s
@@ -44,4 +44,7 @@ foo:
 	vpbroadcastq stderr@GOTPCREL(%rip), %xmm0
 	vpbroadcastq foo@GOTPCREL(%rip), %xmm0
 
+	cmpq foo@GOTPCREL(%rip), %rax
+	cmpq %rax, foo@GOTPCREL(%rip)
+
 .comm foobar,64,32
diff --git a/src/util/fipstools/delocate/testdata/x86_64-GOTRewrite/out.s b/src/util/fipstools/delocate/testdata/x86_64-GOTRewrite/out.s
index 273cfe94..e14a71e6 100644
--- a/src/util/fipstools/delocate/testdata/x86_64-GOTRewrite/out.s
+++ b/src/util/fipstools/delocate/testdata/x86_64-GOTRewrite/out.s
@@ -172,6 +172,21 @@ foo:
 	leaq 128(%rsp), %rsp
 	vpbroadcastq %xmm0, %xmm0
 
+# WAS cmpq foo@GOTPCREL(%rip), %rax
+	leaq -128(%rsp), %rsp
+	pushq %rbx
+	leaq	.Lfoo_local_target(%rip), %rbx
+	cmpq %rbx, %rax
+	popq %rbx
+	leaq 128(%rsp), %rsp
+# WAS cmpq %rax, foo@GOTPCREL(%rip)
+	leaq -128(%rsp), %rsp
+	pushq %rbx
+	leaq	.Lfoo_local_target(%rip), %rbx
+	cmpq %rax, %rbx
+	popq %rbx
+	leaq 128(%rsp), %rsp
+
 .comm foobar,64,32
 .text
 .loc 1 2 0