di: Make the decision about DI in one if-else statement

Instead of doing that in two random places, keep just one if-else
statement which either:

* Sanitizes the debug info, when `--btf` is enabled.
* Strips the debug info, when `--btf` is disabled.

Also, there is no need to call `DISanitizer::run` in an unsafe
block, it's a safe method.

src/linker.rs

@@ -450,12 +450,16 @@ impl Linker {
         // run optimizations. Will optionally remove noinline attributes, intern all non exported
         // programs and maps and remove dead code.
 
-        unsafe {
+        if self.options.btf {
             // if we want to emit BTF, we need to sanitize the debug information
-            if self.options.btf {
-                llvm::DISanitizer::new(self.context, self.module).run(&self.options.export_symbols);
-            }
+            llvm::DISanitizer::new(self.context, self.module).run(&self.options.export_symbols);
+        } else {
+            // if we don't need BTF emission, we can strip DI
+            let ok = unsafe { llvm::strip_debug_info(self.module) };
+            debug!("Stripping DI, changed={}", ok);
+        }
 
+        unsafe {
             llvm::optimize(
                 self.target_machine,
                 self.module,
@@ -466,12 +470,6 @@ impl Linker {
         }
         .map_err(LinkerError::OptimizeError)?;
 
-        // if we don't need BTF emission, we can strip DI
-        if !self.options.btf {
-            let ok = unsafe { llvm::strip_debug_info(self.module) };
-            debug!("Stripping DI, changed={}", ok);
-        }
-
         Ok(())
     }