Merge pull request #28 from klauspost/fix-line-comment-crash

Fix crash on line comments that start with a star.

asmfmt.go

@@ -67,20 +67,18 @@ func (f *fstate) addLine(b []byte) error {
 		return fmt.Errorf("zero (0) byte in input. file is unlikely an assembler file")
 	}
 	s := string(b)
-	s = strings.TrimSpace(s)
 	// Inside block comment
 	if f.insideBlock {
 		defer func() {
 			f.lastComment = true
 		}()
 		if strings.Contains(s, "*/") {
 			ends := strings.Index(s, "*/")
-			end := strings.TrimSpace(s[:ends])
-			if f.lastStar {
-				end = end + " */"
-			} else {
-				end = end + "*/"
+			end := s[:ends]
+			if strings.HasPrefix(strings.TrimSpace(s), "*") && f.lastStar {
+				end = strings.TrimSpace(end) + " "
 			}
+			end = end + "*/"
 			f.insideBlock = false
 			s = strings.TrimSpace(s[ends+2:])
 			if strings.HasSuffix(s, "\\") {
@@ -95,7 +93,8 @@ func (f *fstate) addLine(b []byte) error {
 			}
 		} else {
 			// Insert a space on lines that begin with '*'
-			if strings.HasPrefix(s, "*") {
+			if strings.HasPrefix(strings.TrimSpace(s), "*") {
+				s = strings.TrimSpace(s)
 				f.out.WriteByte(' ')
 				f.lastStar = true
 			} else {
@@ -105,6 +104,7 @@ func (f *fstate) addLine(b []byte) error {
 			return nil
 		}
 	}
+	s = strings.TrimSpace(s)
 
 	// Comment is the the only line content.
 	if strings.HasPrefix(s, "//") {
@@ -141,6 +141,15 @@ func (f *fstate) addLine(b []byte) error {
 	if strings.Contains(s, "/*") && !strings.HasSuffix(s, `\`) {
 		starts := strings.Index(s, "/*")
 		ends := strings.Index(s, "*/")
+		lineComment := strings.Index(s, "//")
+		if lineComment >= 0 {
+			if lineComment < starts {
+				goto exitcomm
+			}
+			if lineComment < ends && !f.insideBlock {
+				goto exitcomm
+			}
+		}
 		pre := s[:starts]
 		pre = strings.TrimSpace(pre)
 

testdata/mod_math_amd64.golden

@@ -1,7 +1,7 @@
 /*
 Quicker way of loading MOD_P ?
-MOVL    $-1, R8
-NEGQ    R8
+        MOVL    $-1, R8
+        NEGQ    R8
 */
 #define MOD_P 0xFFFFFFFF00000001
 

testdata/nested_comment.golden

@@ -0,0 +1,28 @@
+#include "textflag.h"
+
+TEXT ·FailsFormatting(SB), NOSPLIT, $0
+	RET // */
+
+TEXT ·FailsFormatting(SB), NOSPLIT, $0
+/*
+        RET //*/
+
+TEXT ·FailsFormatting(SB), NOSPLIT, $0
+	RET // Some longer comment*/
+
+TEXT ·FailsFormatting(SB), NOSPLIT, $0
+/*
+        RET // Some longer comment*/
+
+TEXT ·FailsFormatting(SB), NOSPLIT, $0
+	/*        RET // */
+
+/*
+	TESTL	BX, BX
+	JEQ	move_0
+	CMPL	BX, $2
+	JBE	move_1or2
+	CMPL	BX, $4
+	JBE	move_3or4
+	CMPL	BX, $8
+*/

testdata/nested_comment.in

@@ -0,0 +1,30 @@
+#include "textflag.h"
+
+TEXT ·FailsFormatting(SB), NOSPLIT, $0
+        RET //*/
+
+
+TEXT ·FailsFormatting(SB), NOSPLIT, $0
+/*
+        RET //*/
+
+TEXT ·FailsFormatting(SB), NOSPLIT, $0
+        RET // Some longer comment*/
+
+
+TEXT ·FailsFormatting(SB), NOSPLIT, $0
+/*
+        RET // Some longer comment*/
+
+TEXT ·FailsFormatting(SB), NOSPLIT, $0
+/*        RET //*/
+
+/*
+	TESTL	BX, BX
+	JEQ	move_0
+	CMPL	BX, $2
+	JBE	move_1or2
+	CMPL	BX, $4
+	JBE	move_3or4
+	CMPL	BX, $8
+*/