[wip] fixed an exception bug: when finding a catch block, by mistake we

still restored callee-saved registers, should directly jump to it

src/compiler/backend/arch/x86_64/asm_backend.rs

@@ -470,7 +470,7 @@ impl ASMCode {
             None
         } else {
             let mut cur = i;
-            while cur >= 0 {
+            loop {
                 if !asm[cur].is_symbol {
                     return Some(cur);
                 }
@@ -481,8 +481,6 @@ impl ASMCode {
                     cur -= 1;
                 }
             }
-
-            None
         }
     }
 

src/compiler/backend/arch/x86_64/mod.rs

@@ -81,7 +81,7 @@ macro_rules! FPR {
 
 GPR_ALIAS!(RAX_ALIAS: (0, RAX)  -> EAX, AX , AL, AH);
 GPR_ALIAS!(RCX_ALIAS: (5, RCX)  -> ECX, CX , CL, CH);
-GPR_ALIAS!(RDX_ALIAS: (10, RDX)  -> EDX, DX , DL, DH);
+GPR_ALIAS!(RDX_ALIAS: (10,RDX)  -> EDX, DX , DL, DH);
 GPR_ALIAS!(RBX_ALIAS: (15,RBX)  -> EBX, BX , BL, BH);
 GPR_ALIAS!(RSP_ALIAS: (20,RSP)  -> ESP, SP , SPL);
 GPR_ALIAS!(RBP_ALIAS: (24,RBP)  -> EBP, BP , BPL);

src/runtime/exception_x64.rs

@@ -102,41 +102,21 @@ pub extern fn throw_exception_internal(exception_obj: Address, last_frame_callee
             rwlock_cf.frame.clone()
         };
         trace!("frame info: {}", frame);
-        
-        // update callee saved register location
-        for reg in x86_64::CALLEE_SAVED_GPRs.iter() {
-            let reg_id = reg.id();
-            trace!("update callee saved register {}", reg_id);
-            if frame.allocated.contains_key(&reg_id) {
-                let offset_from_rbp = frame.allocated.get(&reg_id).unwrap().offset;
-                let reg_restore_addr = cursor.rbp.offset(offset_from_rbp);
-                
-                trace!("update callee saved register {} with loc 0x{:x}", reg_id, reg_restore_addr);
-                cursor.callee_saved_locs.insert(reg_id, reg_restore_addr);
-            } else {
-                // rbp won't find a location
-                if reg_id == x86_64::RBP.id() {
-                    
-                } else {
-                    info!("failed to find an entry for {} in current frame", reg_id);
-                }
-            }
-        }
-        
+
         // find exception block - comparing callsite with frame info
         trace!("checking catch block: looking for callsite 0x{:x}", callsite);
         let exception_callsites = frame.get_exception_callsites();
         for &(ref possible_callsite, ref dest) in exception_callsites.iter() {
             let possible_callsite_addr = possible_callsite.to_address();
             trace!("..check {} at 0x{:x}", possible_callsite, possible_callsite_addr);
-            
+
             if callsite == possible_callsite_addr {
                 trace!("found catch block at {}", dest);
                 // found an exception block
                 let dest_addr = dest.to_address();
-                
+
                 // restore callee saved register and jump to dest_addr
-                
+
                 // prepare a plain array [rbx, rbp, r12, r13, r14, r15]
                 macro_rules! unpack_callee_saved_from_cursor {
                     ($reg: expr) => {
@@ -149,7 +129,7 @@ pub extern fn throw_exception_internal(exception_obj: Address, last_frame_callee
                         }
                     }
                 };
-                
+
                 let rbx = unpack_callee_saved_from_cursor!(x86_64::RBX);
                 let r12 = unpack_callee_saved_from_cursor!(x86_64::R12);
                 let r13 = unpack_callee_saved_from_cursor!(x86_64::R13);
@@ -157,16 +137,36 @@ pub extern fn throw_exception_internal(exception_obj: Address, last_frame_callee
                 let r15 = unpack_callee_saved_from_cursor!(x86_64::R15);
                 let rbp = cursor.rbp.as_usize() as Word;
                 let array = vec![rbx, rbp, r12, r13, r14, r15];
-                
+
                 let rsp = cursor.rbp.offset(frame.cur_offset());
 
                 info!("going to restore thread to {} with RSP {}", dest_addr, rsp);
                 unsafe {thread::exception_restore(dest_addr, array.as_ptr(), rsp)};
-                
+
                 unreachable!()
             }
         }
         trace!("didnt find a catch block");
+
+        // update callee saved register location
+        for reg in x86_64::CALLEE_SAVED_GPRs.iter() {
+            let reg_id = reg.id();
+            trace!("update callee saved register {}", reg.name().unwrap());
+            if frame.allocated.contains_key(&reg_id) {
+                let offset_from_rbp = frame.allocated.get(&reg_id).unwrap().offset;
+                let reg_restore_addr = cursor.rbp.offset(offset_from_rbp);
+                
+                trace!("update callee saved register {} with loc 0x{:x}", reg.name().unwrap(), reg_restore_addr);
+                cursor.callee_saved_locs.insert(reg_id, reg_restore_addr);
+            } else {
+                // rbp won't find a location
+                if reg_id == x86_64::RBP.id() {
+                    info!("skip RBP");
+                } else {
+                    info!("failed to find an entry for {} in current frame", reg.name().unwrap());
+                }
+            }
+        }
         
         // keep unwinding
         callsite = cursor.return_addr;
@@ -239,7 +239,8 @@ impl fmt::Display for FrameCursor {
         writeln!(f, "  rbp=0x{:x}, return_addr=0x{:x}, func_id={}, func_version_id={}", self.rbp, self.return_addr, self.func_id, self.func_ver_id).unwrap();
         writeln!(f, "  callee_saved:").unwrap();
         for (reg, addr) in self.callee_saved_locs.iter() {
-            writeln!(f, "    #{} at 0x{:x}", reg, addr).unwrap()
+            let val = unsafe {addr.load::<u64>()};
+            writeln!(f, "    #{} at 0x{:x} (value=0x{:x}", reg, addr, val).unwrap()
         }
         writeln!(f, "}}")
     }

tests/test_compiler/test_exception.rs

@@ -312,7 +312,6 @@ fn throw_catch_dont_use_exception_arg() -> VM {
 }
 
 #[test]
-#[ignore]
 // issue: didn't restore callee-saved register correctly, temporarily ignore this test
 // FIXME: fix the bug
 fn test_exception_throw_catch_and_add() {
@@ -455,13 +454,23 @@ fn create_catch_exception_and_add(vm: &VM) {
     inst!       ((vm, catch_and_add_v1) blk_exception_px4:
         PRINTHEX ev4
     );
+    // load and print exc_arg
+    let iref_int64 = vm.get_type(vm.id_of("iref_int64"));
+    ssa!        ((vm, catch_and_add_v1) <iref_int64> exc_iref);
+    inst!       ((vm, catch_and_add_v1) blk_exception_getiref:
+        exc_iref = GETIREF exc_arg
+    );
+    ssa!        ((vm, catch_and_add_v1) <int64> exc_val);
+    inst!       ((vm, catch_and_add_v1) blk_exception_load_exc:
+        exc_val = LOAD exc_iref (is_ptr: false, order: MemoryOrder::SeqCst)
+    );
     inst!       ((vm, catch_and_add_v1) blk_exception_px5:
-        PRINTHEX exc_arg
+        PRINTHEX exc_val
     );
 
     ssa!        ((vm, catch_and_add_v1) <int64> res0);
     inst!       ((vm, catch_and_add_v1) blk_exception_add0:
-        res0 = BINOP (BinOp::Add) exc_arg ev0
+        res0 = BINOP (BinOp::Add) exc_val ev0
     );
 
     ssa!        ((vm, catch_and_add_v1) <int64> res1);
@@ -496,6 +505,9 @@ fn create_catch_exception_and_add(vm: &VM) {
         blk_exception_px2,
         blk_exception_px3,
         blk_exception_px4,
+
+        blk_exception_getiref,
+        blk_exception_load_exc,
         blk_exception_px5,
 
         blk_exception_add0,