From 6b5346534746d4e81525109869b836359175ba1d Mon Sep 17 00:00:00 2001
From: Meng Zhuo <mengzhuo@iscas.ac.cn>
Date: Sun, 31 May 2026 22:36:41 +0800
Subject: [PATCH] riscv64: enable gen_clear_cache with I-cache flushing

Wire gen_clear_cache to __riscv64_clear_cache builtin, emitting
fence.i for instruction cache synchronization.
Add lib/riscvflush.c to provide __clear_cache for JIT bootstrap.
Extend tccrun.c I-cache flush guard to include RISC-V targets.
Add gen_clear_cache declaration to tcc.h riscv64 section.
---
 lib/Makefile     |  2 +-
 lib/riscvflush.c | 10 ++++++++++
 tcc.h            |  1 +
 tccgen.c         | 13 +++++++++++++
 tccrun.c         |  2 +-
 tcctok.h         |  7 ++++++-
 6 files changed, 32 insertions(+), 3 deletions(-)
 create mode 100644 lib/riscvflush.c

diff --git a/lib/Makefile b/lib/Makefile
index 0afadff5..3ac6f8f0 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -73,7 +73,7 @@ OBJ-arm-vfp = $(OBJ-arm)
 OBJ-arm-eabi = $(OBJ-arm)
 OBJ-arm-eabihf = $(OBJ-arm)
 OBJ-arm-wince = $(ARM_O) $(WIN_O)
-OBJ-riscv64 = $(RISCV64_O) $(LIN_O)
+OBJ-riscv64 = $(RISCV64_O) riscvflush.o $(LIN_O)
 
 OBJ-extra = $(filter $(EXTRA_O),$(OBJ-$T))
 OBJ-libtcc1 = $(addprefix $(X),$(filter-out $(OBJ-extra),$(OBJ-$T)))
diff --git a/lib/riscvflush.c b/lib/riscvflush.c
new file mode 100644
index 00000000..995bbfc8
--- /dev/null
+++ b/lib/riscvflush.c
@@ -0,0 +1,10 @@
+/* riscvflush.c - flush the instruction cache
+
+   __clear_cache is used in tccrun.c,  It is a built-in
+   intrinsic with gcc.  However tcc in order to compile
+   itself needs this function */
+
+void __clear_cache(void *beg, void *end)
+{
+    __riscv64_clear_cache(beg, end);
+}
diff --git a/tcc.h b/tcc.h
index c74fae47..d22ed534 100644
--- a/tcc.h
+++ b/tcc.h
@@ -1730,6 +1730,7 @@ ST_FUNC void arch_transfer_ret_regs(int);
 ST_FUNC void gen_cvt_sxtw(void);
 ST_FUNC void gen_cvt_csti(int t);
 ST_FUNC void gen_increment_tcov (SValue *sv);
+ST_FUNC void gen_clear_cache(void);
 #endif
 
 /* ------------ c67-gen.c ------------ */
diff --git a/tccgen.c b/tccgen.c
index 7d1381f8..a5df8876 100644
--- a/tccgen.c
+++ b/tccgen.c
@@ -5953,6 +5953,8 @@ ST_FUNC void unary(void)
         vtop->type = type;
         break;
     }
+#endif
+#ifdef TCC_TARGET_ARM64
     case TOK___arm64_clear_cache: {
 	parse_builtin_params(0, "ee");
         gen_clear_cache();
@@ -5961,6 +5963,17 @@ ST_FUNC void unary(void)
         break;
     }
 #endif
+#ifdef TCC_TARGET_RISCV64
+    case TOK___riscv64_clear_cache: {
+	parse_builtin_params(0, "ee");
+	vpop();
+	vpop();
+        gen_clear_cache();
+        vpushi(0);
+        vtop->type.t = VT_VOID;
+        break;
+    }
+#endif
 
     /* atomic operations */
     case TOK___atomic_store:
diff --git a/tccrun.c b/tccrun.c
index 5d16da9a..b3127413 100644
--- a/tccrun.c
+++ b/tccrun.c
@@ -490,7 +490,7 @@ static int protect_pages(void *ptr, unsigned long length, int mode)
     if (mprotect(ptr, length, protect[mode]))
         return -1;
 /* XXX: BSD sometimes dump core with bad system call */
-# if (defined TCC_TARGET_ARM && !TARGETOS_BSD) || defined TCC_TARGET_ARM64
+# if (defined TCC_TARGET_ARM && !TARGETOS_BSD) || defined TCC_TARGET_ARM64 || defined TCC_TARGET_RISCV64
     if (mode == 0 || mode == 3) {
         void __clear_cache(void *beginning, void *end);
         __clear_cache(ptr, (char *)ptr + length);
diff --git a/tcctok.h b/tcctok.h
index b4f5ba7c..458e106d 100644
--- a/tcctok.h
+++ b/tcctok.h
@@ -307,8 +307,13 @@
 #if defined TCC_TARGET_PE
      DEF(TOK___chkstk, "__chkstk")
 #endif
-#if defined TCC_TARGET_ARM64 || defined TCC_TARGET_RISCV64
+#ifdef TCC_TARGET_ARM64
      DEF(TOK___arm64_clear_cache, "__arm64_clear_cache")
+#endif
+#ifdef TCC_TARGET_RISCV64
+     DEF(TOK___riscv64_clear_cache, "__riscv64_clear_cache")
+#endif
+#if defined TCC_TARGET_ARM64 || defined TCC_TARGET_RISCV64
      DEF(TOK___addtf3, "__addtf3")
      DEF(TOK___subtf3, "__subtf3")
      DEF(TOK___multf3, "__multf3")