grep/pcre2: add GREP_PCRE2_DEBUG_MALLOC debug mode

avar · gitster · commit a39b4003f0e4 · 2021-02-17T16:32:19.000-08:00
Add optional printing of PCREv2 allocations to stderr for a developer
who manually changes the GREP_PCRE2_DEBUG_MALLOC definition to "1".

You need to manually change the definition in the source file similar
to the DEBUG_MAILMAP, there's no Makefile knob for this.

This will be referenced a subsequent commit, and is generally useful
to manually see what's going on with PCREv2 allocations while working
on that code.

Signed-off-by: Ævar Arnfjörð Bjarmason &lt;avarab@gmail.com&gt;
Signed-off-by: Junio C Hamano &lt;gitster@pobox.com&gt;
diff --git a/grep.c b/grep.c
@@ -42,15 +42,25 @@ static struct grep_opt grep_defaults = {
 
 #ifdef USE_LIBPCRE2
 static pcre2_general_context *pcre2_global_context;
+#define GREP_PCRE2_DEBUG_MALLOC 0
 
 static void *pcre2_malloc(PCRE2_SIZE size, MAYBE_UNUSED void *memory_data)
 {
 	void *pointer = malloc(size);
+#if GREP_PCRE2_DEBUG_MALLOC
+	static int count = 1;
+	fprintf(stderr, "PCRE2:%p -> #%02d: alloc(%lu)\n", pointer, count++, size);
+#endif
 	return pointer;
 }
 
 static void pcre2_free(void *pointer, MAYBE_UNUSED void *memory_data)
 {
+#if GREP_PCRE2_DEBUG_MALLOC
+	static int count = 1;
+	if (pointer)
+		fprintf(stderr, "PCRE2:%p -> #%02d: free()\n", pointer, count++);
+#endif
 	free(pointer);
 }
 #endif

Original file line number	Diff line number	Diff line change
`@@ -42,15 +42,25 @@ static struct grep_opt grep_defaults = {`
`42`	`42`
`43`	`43`	`#ifdef USE_LIBPCRE2`
`44`	`44`	`static pcre2_general_context *pcre2_global_context;`
	`45`	`+#define GREP_PCRE2_DEBUG_MALLOC 0`
`45`	`46`
`46`	`47`	`static void pcre2_malloc(PCRE2_SIZE size, MAYBE_UNUSED void memory_data)`
`47`	`48`	`{`
`48`	`49`	`void *pointer = malloc(size);`
	`50`	`+#if GREP_PCRE2_DEBUG_MALLOC`
	`51`	`+ static int count = 1;`
	`52`	`+ fprintf(stderr, "PCRE2:%p -> #%02d: alloc(%lu)\n", pointer, count++, size);`
	`53`	`+#endif`
`49`	`54`	`return pointer;`
`50`	`55`	`}`
`51`	`56`
`52`	`57`	`static void pcre2_free(void pointer, MAYBE_UNUSED void memory_data)`
`53`	`58`	`{`
	`59`	`+#if GREP_PCRE2_DEBUG_MALLOC`
	`60`	`+ static int count = 1;`
	`61`	`+ if (pointer)`
	`62`	`+ fprintf(stderr, "PCRE2:%p -> #%02d: free()\n", pointer, count++);`
	`63`	`+#endif`
`54`	`64`	`free(pointer);`
`55`	`65`	`}`
`56`	`66`	`#endif`