pkg/cover/backend: remove RestorePC

Now that PCs are 64-bit we don't need RestorePC callback.
Now we can just use PreviousInstructionPC, which does not require
creation of ReportGenerator.

5 files changed, 10 insertions, 14 deletions

diff --git a/pkg/cover/backend/backend.go b/pkg/cover/backend/backend.go
index 5aa6a221c..b390f5cad 100644
--- a/pkg/cover/backend/backend.go
+++ b/pkg/cover/backend/backend.go
@@ -14,7 +14,6 @@ type Impl struct {
 	Symbols         []*Symbol
 	Frames          []Frame
 	Symbolize       func(pcs map[*Module][]uint64) ([]Frame, error)
-	RestorePC       func(pc uint64) uint64
 	CallbackPoints  []uint64
 	PreciseCoverage bool
 }
diff --git a/pkg/cover/backend/dwarf.go b/pkg/cover/backend/dwarf.go
index 3f64cf752..a1f2b3e1e 100644
--- a/pkg/cover/backend/dwarf.go
+++ b/pkg/cover/backend/dwarf.go
@@ -223,19 +223,12 @@ func makeDWARFUnsafe(params *dwarfParams) (*Impl, error) {
 		Symbolize: func(pcs map[*Module][]uint64) ([]Frame, error) {
 			return symbolize(target, &interner, objDir, srcDir, buildDir, splitBuildDelimiters, pcs)
 		},
-		RestorePC:       makeRestorePC(params),
 		CallbackPoints:  allCoverPoints[0],
 		PreciseCoverage: preciseCoverage,
 	}
 	return impl, nil
 }
 
-func makeRestorePC(params *dwarfParams) func(pc uint64) uint64 {
-	return func(pc uint64) uint64 {
-		return PreviousInstructionPC(params.target, pc)
-	}
-}
-
 func buildSymbols(symbols []*Symbol, ranges []pcRange, coverPoints [2][]uint64) []*Symbol {
 	// Assign coverage point PCs to symbols.
 	// Both symbols and coverage points are sorted, so we do it one pass over both.
diff --git a/pkg/cover/backend/gvisor.go b/pkg/cover/backend/gvisor.go
index 65a3da9a2..9d4fc68b3 100644
--- a/pkg/cover/backend/gvisor.go
+++ b/pkg/cover/backend/gvisor.go
@@ -48,9 +48,6 @@ func makeGvisor(target *targets.Target, objDir, srcDir, buildDir string, modules
 	impl := &Impl{
 		Units:  units,
 		Frames: frames,
-		RestorePC: func(pc uint64) uint64 {
-			return pc
-		},
 	}
 	return impl, nil
 }
diff --git a/pkg/cover/backend/pc.go b/pkg/cover/backend/pc.go
index 10462c243..24b4b296e 100644
--- a/pkg/cover/backend/pc.go
+++ b/pkg/cover/backend/pc.go
@@ -9,7 +9,11 @@ import (
 	"github.com/google/syzkaller/sys/targets"
 )
 
-func PreviousInstructionPC(target *targets.Target, pc uint64) uint64 {
+func PreviousInstructionPC(target *targets.Target, vm string, pc uint64) uint64 {
+	if vm == "gvisor" {
+		// gVisor coverage returns real PCs that don't need adjustment.
+		return pc
+	}
 	offset := instructionLen(target.Arch)
 	pc -= offset
 	// THUMB instructions are 2 or 4 bytes with low bit set.
@@ -20,7 +24,10 @@ func PreviousInstructionPC(target *targets.Target, pc uint64) uint64 {
 	return pc
 }
 
-func NextInstructionPC(target *targets.Target, pc uint64) uint64 {
+func NextInstructionPC(target *targets.Target, vm string, pc uint64) uint64 {
+	if vm == "gvisor" {
+		return pc
+	}
 	offset := instructionLen(target.Arch)
 	pc += offset
 	// THUMB instructions are 2 or 4 bytes with low bit set.
diff --git a/pkg/cover/report_test.go b/pkg/cover/report_test.go
index 07ae439ac..7ce519c83 100644
--- a/pkg/cover/report_test.go
+++ b/pkg/cover/report_test.go
@@ -348,7 +348,7 @@ func generateReport(t *testing.T, target *targets.Target, test *Test) (*reports,
 			if err != nil {
 				t.Fatal(err)
 			}
-			pcs = append(pcs, backend.PreviousInstructionPC(target, pc))
+			pcs = append(pcs, backend.PreviousInstructionPC(target, "", pc))
 			t.Logf("using exact coverage PC 0x%x", pcs[0])
 		} else if target.OS == runtime.GOOS && (target.Arch == runtime.GOARCH || target.VMArch == runtime.GOARCH) {
 			t.Fatal(err)