all: fix arm64 runtime pc not align with elf

2 files changed, 24 insertions, 14 deletions

diff --git a/pkg/cover/backend/dwarf.go b/pkg/cover/backend/dwarf.go
index 23a1e8ce9..7a9abd221 100644
--- a/pkg/cover/backend/dwarf.go
+++ b/pkg/cover/backend/dwarf.go
@@ -7,6 +7,7 @@ import (
 	"bufio"
 	"bytes"
 	"debug/dwarf"
+	"debug/elf"
 	"encoding/binary"
 	"fmt"
 	"io/ioutil"
@@ -30,25 +31,30 @@ type containerFns struct {
 }
 
 type Arch struct {
-	callLen      int
-	opcodeOffset int
-	opcodes      [2]byte
-	target       func(arch *Arch, insn []byte, pc uint64, opcode byte) uint64
+	callLen       int
+	relaOffset    uint64
+	opcodeOffset  int
+	opcodes       [2]byte
+	callRelocType uint64
+	target        func(arch *Arch, insn []byte, pc uint64, opcode byte) uint64
 }
 
 var arches = map[string]Arch{
 	targets.AMD64: {
-		callLen: 5,
-		opcodes: [2]byte{0xe8, 0xe8},
+		callLen:       5,
+		relaOffset:    1,
+		opcodes:       [2]byte{0xe8, 0xe8},
+		callRelocType: uint64(elf.R_X86_64_PLT32),
 		target: func(arch *Arch, insn []byte, pc uint64, opcode byte) uint64 {
 			off := uint64(int64(int32(binary.LittleEndian.Uint32(insn[1:]))))
 			return pc + off + uint64(arch.callLen)
 		},
 	},
 	targets.ARM64: {
-		callLen:      4,
-		opcodeOffset: 3,
-		opcodes:      [2]byte{0x94, 0x97},
+		callLen:       4,
+		opcodeOffset:  3,
+		opcodes:       [2]byte{0x94, 0x97},
+		callRelocType: uint64(elf.R_AARCH64_CALL26),
 		target: func(arch *Arch, insn []byte, pc uint64, opcode byte) uint64 {
 			off := uint64(binary.LittleEndian.Uint32(insn)) & ((1 << 24) - 1)
 			if opcode == arch.opcodes[1] {
diff --git a/pkg/cover/backend/elf.go b/pkg/cover/backend/elf.go
index 94e6fdd8c..227356eef 100644
--- a/pkg/cover/backend/elf.go
+++ b/pkg/cover/backend/elf.go
@@ -40,7 +40,9 @@ func elfReadSymbols(module *Module, info *symbolInfo) ([]*Symbol, error) {
 	if err != nil {
 		return nil, fmt.Errorf("failed to read ELF symbols: %v", err)
 	}
-	info.textAddr = text.Addr
+	if module.Name == "" {
+		info.textAddr = text.Addr
+	}
 	var symbols []*Symbol
 	for i, symb := range allSymbols {
 		text := symb.Value >= text.Addr && symb.Value+symb.Size <= text.Addr+text.Size
@@ -133,7 +135,8 @@ func elfReadModuleCoverPoints(target *targets.Target, module *Module, info *symb
 	if err != nil {
 		return pcs, err
 	}
-	offset := uint64(arches[target.Arch].opcodeOffset)
+	callRelocType := arches[target.Arch].callRelocType
+	relaOffset := arches[target.Arch].relaOffset
 	for _, s := range file.Sections {
 		if s.Type != elf.SHT_RELA { // nolint: misspell
 			continue
@@ -146,10 +149,11 @@ func elfReadModuleCoverPoints(target *targets.Target, module *Module, info *symb
 				}
 				return pcs, err
 			}
-			// Note: this assumes that call instruction is 1 byte.
-			pc := module.Addr + rel.Off - 1
+			if (rel.Info & 0xffffffff) != callRelocType {
+				continue
+			}
+			pc := module.Addr + rel.Off - relaOffset
 			index := int(elf.R_SYM64(rel.Info)) - 1
-			pc -= offset
 			if info.tracePCIdx[index] {
 				pcs[0] = append(pcs[0], pc)
 			} else if info.traceCmpIdx[index] {