pa2.2: add ITRACE buffer

nemu/Kconfig

@@ -151,6 +151,10 @@ config ITRACE_COND
   string "Only trace instructions when the condition is true"
   default "true"
 
+config ITRACE_BUFFER
+  depends on ITRACE
+  int "Buffer size for intruction trace (unit: number of instructions)"
+  default 10
 
 config DIFFTEST
   depends on TARGET_NATIVE_ELF

nemu/include/cpu/decode.h

@@ -23,7 +23,6 @@ typedef struct Decode {
   vaddr_t snpc; // static next pc
   vaddr_t dnpc; // dynamic next pc
   ISADecodeInfo isa;
-  IFDEF(CONFIG_ITRACE, char logbuf[128]);
 } Decode;
 
 // --- pattern matching mechanism ---

nemu/include/debug.h

@@ -38,6 +38,7 @@
       MUXDEF(CONFIG_TARGET_AM, printf(ANSI_FMT(format, ANSI_FG_RED) "\n", ## __VA_ARGS__), \
         (fflush(stdout), fprintf(stderr, ANSI_FMT(format, ANSI_FG_RED) "\n", ##  __VA_ARGS__))); \
       IFNDEF(CONFIG_TARGET_AM, extern FILE* log_fp; fflush(log_fp)); \
+      IFDEF(CONFIG_ITRACE, log_itrace_print()); \
       extern void assert_fail_msg(); \
       assert_fail_msg(); \
       assert(cond); \

nemu/include/utils.h

@@ -74,4 +74,7 @@ uint64_t get_time();
   } while (0)
 
 
+IFDEF(CONFIG_ITRACE, void log_itrace_print());
+
+
 #endif

nemu/src/cpu/cpu-exec.c

@@ -13,6 +13,7 @@
 * See the Mulan PSL v2 for more details.
 ***************************************************************************************/
 
+#include "utils.h"
 #include <cpu/cpu.h>
 #include <cpu/decode.h>
 #include <cpu/difftest.h>
@@ -29,15 +30,17 @@ CPU_state cpu = {};
 uint64_t g_nr_guest_inst = 0;
 static uint64_t g_timer = 0; // unit: us
 static bool g_print_step = false;
+IFDEF(CONFIG_ITRACE, extern char logbuf[CONFIG_ITRACE_BUFFER][128]);
+IFDEF(CONFIG_ITRACE, extern int logbuf_rear);
 
 void device_update();
 bool wp_eval_all();
 
 static void trace_and_difftest(Decode *_this, vaddr_t dnpc) {
 #ifdef CONFIG_ITRACE_COND
-  if (ITRACE_COND) { log_write("%s\n", _this->logbuf); }
+  if (ITRACE_COND) { log_write("%s\n", logbuf[logbuf_rear]); }
 #endif
-  if (g_print_step) { IFDEF(CONFIG_ITRACE, puts(_this->logbuf)); }
+  if (g_print_step) { IFDEF(CONFIG_ITRACE, puts(logbuf[logbuf_rear])); }
   IFDEF(CONFIG_DIFFTEST, difftest_step(_this->pc, dnpc));
 }
 
@@ -47,8 +50,9 @@ static void exec_once(Decode *s, vaddr_t pc) {
   isa_exec_once(s);
   cpu.pc = s->dnpc;
 #ifdef CONFIG_ITRACE
-  char *p = s->logbuf;
-  p += snprintf(p, sizeof(s->logbuf), FMT_WORD ":", s->pc);
+  logbuf_rear = (logbuf_rear + 1) % CONFIG_ITRACE_BUFFER;
+  char *p = logbuf[logbuf_rear];
+  p += snprintf(p, sizeof(logbuf), FMT_WORD ":", s->pc);
   int ilen = s->snpc - s->pc;
   int i;
   uint8_t *inst = (uint8_t *)&s->isa.inst.val;
@@ -64,7 +68,7 @@ static void exec_once(Decode *s, vaddr_t pc) {
 
 #ifndef CONFIG_ISA_loongarch32r
   void disassemble(char *str, int size, uint64_t pc, uint8_t *code, int nbyte);
-  disassemble(p, s->logbuf + sizeof(s->logbuf) - p,
+  disassemble(p, logbuf[logbuf_rear] + sizeof(logbuf[logbuf_rear]) - p,
       MUXDEF(CONFIG_ISA_x86, s->snpc, s->pc), (uint8_t *)&s->isa.inst.val, ilen);
 #else
   p[0] = '\0'; // the upstream llvm does not support loongarch32r
@@ -79,7 +83,7 @@ static void execute(uint64_t n) {
     g_nr_guest_inst ++;
     trace_and_difftest(&s, cpu.pc);
     if (wp_eval_all()) { 
-      puts(s.logbuf);
+      puts(logbuf[logbuf_rear]);
       break;
     }
     if (nemu_state.state != NEMU_RUNNING) break;
@@ -121,13 +125,16 @@ void cpu_exec(uint64_t n) {
   switch (nemu_state.state) {
     case NEMU_RUNNING: nemu_state.state = NEMU_STOP; break;
 
-    case NEMU_END: case NEMU_ABORT:
+    case NEMU_END: case NEMU_ABORT: {
       Log("nemu: %s at pc = " FMT_WORD,
           (nemu_state.state == NEMU_ABORT ? ANSI_FMT("ABORT", ANSI_FG_RED) :
            (nemu_state.halt_ret == 0 ? ANSI_FMT("HIT GOOD TRAP", ANSI_FG_GREEN) :
             ANSI_FMT("HIT BAD TRAP", ANSI_FG_RED))),
           nemu_state.halt_pc);
-      // fall through
+      if(nemu_state.halt_ret != 0) {
+        log_itrace_print();
+      }
+    } // fall through
     case NEMU_QUIT: statistic();
   }
 }

nemu/src/isa/riscv32/inst.c

@@ -54,7 +54,7 @@ static void decode_operand(Decode *s, int *rd, word_t *src1, word_t *src2,
 
 static void do_branch(Decode *s, bool condition, word_t offset) {
   if (condition) {
-    puts(s->logbuf);
+    // puts(s->logbuf[s->logbuf_rear]);
     s->dnpc = s->pc + offset;
   }
 }

nemu/src/utils/log.c

@@ -35,3 +35,18 @@ bool log_enable() {
          (g_nr_guest_inst <= CONFIG_TRACE_END), false);
 }
 #endif
+
+IFDEF(CONFIG_ITRACE, char logbuf[CONFIG_ITRACE_BUFFER][128]);
+IFDEF(CONFIG_ITRACE, int logbuf_rear);
+
+#ifdef CONFIG_ITRACE
+void log_itrace_print() {
+  puts("ITRACE buffer:");
+  for (int i = (logbuf_rear + 1) % CONFIG_ITRACE_BUFFER; i != logbuf_rear; i = (i + 1) % CONFIG_ITRACE_BUFFER) {
+    if (logbuf[i][0] == '\0') continue;
+    puts(logbuf[i]);
+  }
+  puts("Current command:");
+  puts(logbuf[logbuf_rear]);
+}
+#endif