Fix prologue detection on testvariables2.go's main.main (#625)

proc/disasm_amd64.go

@@ -119,9 +119,11 @@ type instrseq []x86asm.Op
 
 var windowsPrologue = instrseq{x86asm.MOV, x86asm.MOV, x86asm.LEA, x86asm.CMP, x86asm.JBE}
 var windowsPrologue2 = instrseq{x86asm.MOV, x86asm.MOV, x86asm.CMP, x86asm.JBE}
+var windowsPrologue3 = instrseq{x86asm.MOV, x86asm.MOV, x86asm.MOV, x86asm.CMP, x86asm.JE}
 var unixPrologue = instrseq{x86asm.MOV, x86asm.LEA, x86asm.CMP, x86asm.JBE}
 var unixPrologue2 = instrseq{x86asm.MOV, x86asm.CMP, x86asm.JBE}
-var prologues = []instrseq{windowsPrologue, windowsPrologue2, unixPrologue, unixPrologue2}
+var unixPrologue3 = instrseq{x86asm.MOV, x86asm.MOV, x86asm.CMP, x86asm.JE}
+var prologues = []instrseq{windowsPrologue, windowsPrologue2, unixPrologue, unixPrologue2, unixPrologue3}
 
 // FirstPCAfterPrologue returns the address of the first instruction after the prologue for function fn
 // If sameline is set FirstPCAfterPrologue will always return an address associated with the same line as fn.Entry

proc/eval.go

@@ -11,8 +11,8 @@ import (
 	"go/token"
 	"reflect"
 
-	"golang.org/x/debug/dwarf"
 	"github.com/derekparker/delve/dwarf/reader"
+	"golang.org/x/debug/dwarf"
 )
 
 // EvalExpression returns the value of the given expression.

proc/proc.go

@@ -14,10 +14,10 @@ import (
 	"strings"
 	"sync"
 
-	"golang.org/x/debug/dwarf"
 	"github.com/derekparker/delve/dwarf/frame"
 	"github.com/derekparker/delve/dwarf/line"
 	"github.com/derekparker/delve/dwarf/reader"
+	"golang.org/x/debug/dwarf"
 )
 
 // Process represents all of the information the debugger

proc/proc_linux.go

@@ -18,9 +18,9 @@ import (
 
 	sys "golang.org/x/sys/unix"
 
-	"golang.org/x/debug/elf"
 	"github.com/derekparker/delve/dwarf/frame"
 	"github.com/derekparker/delve/dwarf/line"
+	"golang.org/x/debug/elf"
 )
 
 // Process statuses

proc/proc_test.go

@@ -1882,7 +1882,7 @@ func TestUnsupportedArch(t *testing.T) {
 	}
 }
 
-func Test1Issue573(t *testing.T) {
+func TestIssue573(t *testing.T) {
 	// calls to runtime.duffzero and runtime.duffcopy jump directly into the middle
 	// of the function and the temp breakpoint set by StepInto may be missed.
 	withTestProcess("issue573", t, func(p *Process, fixture protest.Fixture) {
@@ -1895,3 +1895,15 @@ func Test1Issue573(t *testing.T) {
 		assertNoError(p.Step(), t, "Step() #3") // Third step ought to be possible; program ought not have exited.
 	})
 }
+
+func TestTestvariables2Prologue(t *testing.T) {
+	withTestProcess("testvariables2", t, func(p *Process, fixture protest.Fixture) {
+		addrEntry, err := p.FindFunctionLocation("main.main", false, 0)
+		assertNoError(err, t, "FindFunctionLocation - entrypoint")
+		addrPrologue, err := p.FindFunctionLocation("main.main", true, 0)
+		assertNoError(err, t, "FindFunctionLocation - postprologue")
+		if addrEntry == addrPrologue {
+			t.Fatalf("Prologue detection failed on testvariables2.go/main.main")
+		}
+	})
+}

proc/variables.go

@@ -12,9 +12,9 @@ import (
 	"strings"
 	"unsafe"
 
-	"golang.org/x/debug/dwarf"
 	"github.com/derekparker/delve/dwarf/op"
 	"github.com/derekparker/delve/dwarf/reader"
+	"golang.org/x/debug/dwarf"
 )
 
 const (