From d0c7c9d55bf941eeda521dd241c5e0ff248d17e5 Mon Sep 17 00:00:00 2001
From: Zxilly <zhouxinyu1001@gmail.com>
Date: Fri, 26 Jan 2024 04:42:46 +0800
Subject: [PATCH] fix: follow the official objfile implementation

---
 elf.go | 50 ++++++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 44 insertions(+), 6 deletions(-)

diff --git a/elf.go b/elf.go
index 0e15888..541b354 100644
--- a/elf.go
+++ b/elf.go
@@ -82,19 +82,57 @@ func (e *elfFile) GetFile() *os.File {
 	return e.osFile
 }
 
+func (e *elfFile) getSymbolData(start, end string) ([]byte, error) {
+	elfSyms, err := e.file.Symbols()
+	if err != nil {
+		return nil, err
+	}
+	var addr, eaddr uint64
+	for _, s := range elfSyms {
+		if s.Name == start {
+			addr = s.Value
+		} else if s.Name == end {
+			eaddr = s.Value
+		}
+		if addr != 0 && eaddr != 0 {
+			break
+		}
+	}
+	if addr == 0 || eaddr < addr {
+		return nil, fmt.Errorf("could not find the symbol %s", start)
+	}
+	size := eaddr - addr
+	data := make([]byte, size)
+	for _, prog := range e.file.Progs {
+		if prog.Vaddr <= addr && addr+size-1 <= prog.Vaddr+prog.Filesz-1 {
+			if _, err := prog.ReadAt(data, int64(addr-prog.Vaddr)); err != nil {
+				return nil, fmt.Errorf("could not read the symbol data: %w", err)
+			}
+			return data, nil
+		}
+	}
+	return nil, fmt.Errorf("could not find the symbol %s", start)
+}
+
 func (e *elfFile) getPCLNTab() (*gosym.Table, error) {
 	pclnSection := e.file.Section(".gopclntab")
 	if pclnSection == nil {
 		// No section found. Check if the PIE section exist instead.
 		pclnSection = e.file.Section(".data.rel.ro.gopclntab")
 	}
-	if pclnSection == nil {
-		return nil, fmt.Errorf("no gopclntab section found")
-	}
+	var pclndat []byte
+	var err error
 
-	pclndat, err := pclnSection.Data()
-	if err != nil {
-		return nil, fmt.Errorf("could not get the data for the pclntab: %w", err)
+	if pclnSection == nil {
+		pclndat, err = e.getSymbolData("runtime.pclntab", "runtime.epclntab")
+		if err != nil {
+			return nil, fmt.Errorf("could not get the pclntab data: %w", err)
+		}
+	} else {
+		pclndat, err = pclnSection.Data()
+		if err != nil {
+			return nil, fmt.Errorf("could not get the data for the pclntab: %w", err)
+		}
 	}
 
 	var pcln *gosym.LineTable