From 03898249ea80c84f8d580c64875f707d7b782932 Mon Sep 17 00:00:00 2001
From: Alessio Greggi <ale_grey_91@hotmail.it>
Date: Mon, 27 Jan 2025 17:52:11 +0100
Subject: [PATCH] fix: avoid regex compilation for every symbol

Signed-off-by: Alessio Greggi <ale_grey_91@hotmail.it>
---
 cmd/analyze.go                |  9 ++++++---
 internal/elfreader/symbols.go | 22 ++++++++++++----------
 2 files changed, 18 insertions(+), 13 deletions(-)

diff --git a/cmd/analyze.go b/cmd/analyze.go
index 5f4941d..4c6e7d1 100644
--- a/cmd/analyze.go
+++ b/cmd/analyze.go
@@ -102,8 +102,11 @@ var analyzeCmd = &cobra.Command{
 				}
 
 				// retrieving function symbols from ELF file.
-				elf := elfreader.NewElfReader(testBinPath)
-				symbolsFromElf, err := elf.FunctionSymbols(moduleName)
+				elf, err := elfreader.NewElfReader(testBinPath)
+				if err != nil {
+					return fmt.Errorf("failed to initialize elf file: %v", err)
+				}
+				fnSymbols, err := elf.FunctionSymbols(moduleName)
 				if err != nil {
 					return fmt.Errorf("failed to get function symbols: %v", err)
 				}
@@ -115,7 +118,7 @@ var analyzeCmd = &cobra.Command{
 				// in the _test.go files in the same directory.
 				// if not, they will not be included in the report,
 				// so we can avoid useless symbols to be traced.
-				for _, symbol := range symbolsFromElf {
+				for _, symbol := range fnSymbols {
 					functionName := analyzer.ExtractFunctionName(symbol)
 					testFiles, _ := listTestFiles(path)
 					for _, testFile := range testFiles {
diff --git a/internal/elfreader/symbols.go b/internal/elfreader/symbols.go
index a214a82..1765c20 100644
--- a/internal/elfreader/symbols.go
+++ b/internal/elfreader/symbols.go
@@ -11,15 +11,21 @@ type ElfReader struct {
 	file *elf.File
 }
 
+// Regular expression to match ".func" followed by one or more digits
+var reGoroutine = regexp.MustCompile(`\.func\d+$`)
+
+// Regular expression to check for valid Test suffix patterns
+var reTestFunction = regexp.MustCompile(`\.Test[\w.]*$`)
+
 // NewElfReader opens an ELF file and returns the ElfReader struct.
-func NewElfReader(filePath string) *ElfReader {
+func NewElfReader(filePath string) (*ElfReader, error) {
 	elfFile, err := elf.Open(filePath)
 	if err != nil {
-		fmt.Println("error: %w", err)
+		return nil, fmt.Errorf("%v", err)
 	}
 	return &ElfReader{
 		file: elfFile,
-	}
+	}, nil
 }
 
 // Close closes the ElfReader file.
@@ -37,7 +43,7 @@ func (e *ElfReader) FunctionSymbols(pattern string) ([]string, error) {
 	var symbolsList []string
 	for _, symb := range symbols {
 		// filter only function symbols
-		if !(elf.ST_TYPE(symb.Info) == elf.STT_FUNC) {
+		if elf.ST_TYPE(symb.Info) != elf.STT_FUNC {
 			continue
 		}
 		// filter for package related symbols
@@ -63,14 +69,10 @@ func (e *ElfReader) FunctionSymbols(pattern string) ([]string, error) {
 
 // isGoroutine detects if the symbol passed as argument is a goroutine function.
 func isGoroutine(s string) bool {
-	// Regular expression to match ".func" followed by one or more digits
-	re := regexp.MustCompile(`\.func\d+$`)
-	return re.MatchString(s)
+	return reGoroutine.MatchString(s)
 }
 
 // isTestFunction detects if the symbol passed as argument is a Test function.
 func isTestFunction(s string) bool {
-	// Regular expression to check for valid Test suffix patterns
-	re := regexp.MustCompile(`\.Test[\w.]*$`)
-	return re.MatchString(s)
+	return reTestFunction.MatchString(s)
 }