Show demangled linkage name if avaiable

Use c++filt program to demangle the linkage name.

Author: namhyung

Makefile

@@ -6,7 +6,7 @@ CFLAGS += -g -Wno-deprecated-declarations
 
 all: dwarview
 
-dwarview: main.c dwarview.c
+dwarview: main.c dwarview.c demangle.c
 	gcc -o $@ $(CFLAGS) $^ $(LDFLAGS)
 
 clean:

demangle.c

@@ -0,0 +1,88 @@
+/*
+ * Simple demangler interface using the external `c++filt` program.
+ */
+#include <stdio.h>
+#include <unistd.h>
+#include <string.h>
+#include <stdbool.h>
+
+struct demangler {
+	int	in;
+	int	out;
+	bool	ok;
+};
+
+static struct demangler d;
+
+/* popen() doesn't provide bidirectional streams, do it manually */
+void setup_demangler(void)
+{
+    int p1[2], p2[2];
+
+    d.ok = false;
+
+    if (pipe(p1) < 0 || pipe(p2) < 0)
+	    return;
+
+    switch (fork()) {
+    case -1:  /* error */
+	    return;
+
+    case 0:  /* child */
+	    dup2(p1[0], STDIN_FILENO);
+	    dup2(p2[1], STDOUT_FILENO);
+
+	    close(p1[0]);
+	    close(p1[1]);
+	    close(p2[0]);
+	    close(p2[1]);
+
+	    execlp("c++filt", NULL);
+	    break;
+
+    default:  /* parent */
+	    d.in  = p1[1];
+	    d.out = p2[0];
+
+	    close(p1[0]);
+	    close(p2[1]);
+
+	    d.ok = true;
+	    break;
+    }
+}
+
+void finish_demangler(void)
+{
+	if (d.ok) {
+		close(d.in);
+		close(d.out);
+	}
+
+	d.ok = false;
+}
+
+bool demangler_enabled(void)
+{
+	return d.ok;
+}
+
+int demangle(const char *input, char *output, int outlen)
+{
+	int ret;
+	int len = strlen(input);
+	char flush = '\n';
+
+	if (!d.ok) {
+		memcpy(output, input, len+1);
+		return 0;
+	}
+
+	write(d.in, input, len);
+	write(d.in, &flush, 1);
+
+	ret = read(d.out, output, outlen);
+	output[ret - 1] = '\0';
+
+	return ret;
+}

main.c

@@ -93,6 +93,11 @@ struct search_item {
 static void add_contents(GtkBuilder *builder, char *filename);
 static void destroy_item(gpointer data);
 
+extern void setup_demangler(void);
+extern void finish_demangler(void);
+extern bool demangler_enabled(void);
+extern int demangle(const char *input, char *output, int outlen);
+
 /* Get a Dwarf from offline image */
 static int open_dwarf_file(char *path)
 {
@@ -836,14 +841,16 @@ static const char *die_name(Dwarf_Die *die)
 	Dwarf_Die origin;
 	Dwarf_Attribute attr;
 	const char *name;
-
-	name = dwarf_diename(&pos);
-	if (name)
-		return name;
+	static char buf[4096];
 
 	while (true) {
 		if (dwarf_attr(&pos, DW_AT_name, &attr))
 			return dwarf_formstring(&attr);
+		/* use linkage name only if it can demangle the name */
+		if (dwarf_attr(&pos, DW_AT_linkage_name, &attr) && demangler_enabled()) {
+			demangle(dwarf_formstring(&attr), buf, sizeof(buf));
+			return buf;
+		}
 
 		if (dwarf_attr(&pos, DW_AT_abstract_origin, &attr) == NULL &&
 		    dwarf_attr(&pos, DW_AT_specification, &attr) == NULL &&
@@ -1080,6 +1087,8 @@ int main(int argc, char *argv[])
 		return 1;
 	}
 
+	setup_demangler();
+
 	window = GTK_WIDGET(gtk_builder_get_object(builder, "root_window"));
 	gtk_widget_show(window);
 
@@ -1099,5 +1108,7 @@ int main(int argc, char *argv[])
 
 	gtk_main();
 
+	finish_demangler();
+
 	return 0;
 }