Fixup uses of RIP

Author: Porges

src/agent/coverage/src/record/linux.rs

@@ -43,17 +43,22 @@ impl<'data> LinuxRecorder<'data> {
         tracee: &mut Tracee,
     ) -> Result<()> {
         let regs = tracee.registers()?;
-        let addr = Address(regs.rip);
 
-        if let Some(image) = context.find_image_for_addr(addr) {
+        #[cfg(target_arch = "x86_64")]
+        let instruction_pointer = Address(regs.rip);
+
+        #[cfg(target_arch = "aarch64")]
+        let instruction_pointer = Address(regs.pc);
+
+        if let Some(image) = context.find_image_for_addr(instruction_pointer) {
             if let Some(coverage) = self.coverage.modules.get_mut(image.path()) {
-                let offset = addr.offset_from(image.base())?;
+                let offset = instruction_pointer.offset_from(image.base())?;
                 coverage.increment(offset);
             } else {
                 bail!("coverage not initialized for module {}", image.path());
             }
         } else {
-            bail!("no image for addr: {addr:x}");
+            bail!("no image for addr: {instruction_pointer:x}");
         }
 
         Ok(())

src/agent/coverage/src/record/linux/debugger.rs

@@ -131,16 +131,22 @@ impl<'eh> Debugger<'eh> {
     fn restore_and_call_if_breakpoint(&mut self, tracee: &mut Tracee) -> Result<()> {
         let mut regs = tracee.registers()?;
 
+        #[cfg(target_arch = "x86_64")]
+        let instruction_pointer = &mut regs.rip;
+
+        #[cfg(target_arch = "aarch64")]
+        let instruction_pointer = &mut regs.pc;
+
         // Compute what the last PC would have been _if_ we stopped due to a soft breakpoint.
         //
         // If we don't have a registered breakpoint, then we will not use this value.
-        let pc = Address(regs.rip.saturating_sub(1));
+        let pc = Address(instruction_pointer.saturating_sub(1));
 
         if self.context.breakpoints.clear(tracee, pc)? {
             // We restored the original, `int3`-clobbered instruction in `clear()`. Now
             // set the tracee's registers to execute it on restart. Do this _before_ the
             // callback to simulate a hardware breakpoint.
-            regs.rip = pc.0;
+            *instruction_pointer = pc.0;
             tracee.set_registers(regs)?;
 
             self.event_handler