[PATCH 18/23] tcg/tci: Move stack bounds check to compile-time

[Richard Henderson]

The existing check was incomplete:
(1) Only applied to two of the 7 stores, and not to the loads at all.
(2) Only checked the upper, but not the lower bound of the stack.

Doing this at compile time means that we don't need to do it
at runtime as well.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 tcg/tci.c                |  2 --
 tcg/tci/tcg-target.c.inc | 13 +++++++++++++
 2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/tcg/tci.c b/tcg/tci.c
index 67875636a5..c4c303f874 100644
--- a/tcg/tci.c
+++ b/tcg/tci.c
@@ -623,7 +623,6 @@ uintptr_t QEMU_DISABLE_CFI tcg_qemu_tb_exec(CPUArchState 
*env,
             t0 = tci_read_r32(regs, &tb_ptr);
             t1 = tci_read_r(regs, &tb_ptr);
             t2 = tci_read_s32(&tb_ptr);
-            tci_assert(t1 != sp_value || (int32_t)t2 < 0);
             *(uint32_t *)(t1 + t2) = t0;
             break;
 
@@ -879,7 +878,6 @@ uintptr_t QEMU_DISABLE_CFI tcg_qemu_tb_exec(CPUArchState 
*env,
             t0 = tci_read_r64(regs, &tb_ptr);
             t1 = tci_read_r(regs, &tb_ptr);
             t2 = tci_read_s32(&tb_ptr);
-            tci_assert(t1 != sp_value || (int32_t)t2 < 0);
             *(uint64_t *)(t1 + t2) = t0;
             break;
 
diff --git a/tcg/tci/tcg-target.c.inc b/tcg/tci/tcg-target.c.inc
index 15981265db..a60fa524a4 100644
--- a/tcg/tci/tcg-target.c.inc
+++ b/tcg/tci/tcg-target.c.inc
@@ -484,10 +484,20 @@ static void tci_out_label(TCGContext *s, TCGLabel *label)
     }
 }
 
+static void stack_bounds_check(TCGReg base, target_long offset)
+{
+    if (base == TCG_REG_CALL_STACK) {
+        tcg_debug_assert(offset < 0);
+        tcg_debug_assert(offset >= -(CPU_TEMP_BUF_NLONGS * sizeof(long)));
+    }
+}
+
 static void tcg_out_ld(TCGContext *s, TCGType type, TCGReg ret, TCGReg arg1,
                        intptr_t arg2)
 {
     uint8_t *old_code_ptr = s->code_ptr;
+
+    stack_bounds_check(arg1, arg2);
     if (type == TCG_TYPE_I32) {
         tcg_out_op_t(s, INDEX_op_ld_i32);
         tcg_out_r(s, ret);
@@ -623,6 +633,7 @@ static void tcg_out_op(TCGContext *s, TCGOpcode opc, const 
TCGArg *args,
     case INDEX_op_st16_i64:
     case INDEX_op_st32_i64:
     case INDEX_op_st_i64:
+        stack_bounds_check(args[1], args[2]);
         tcg_out_r(s, args[0]);
         tcg_out_r(s, args[1]);
         tcg_debug_assert(args[2] == (int32_t)args[2]);
@@ -825,6 +836,8 @@ static void tcg_out_st(TCGContext *s, TCGType type, TCGReg 
arg, TCGReg arg1,
                        intptr_t arg2)
 {
     uint8_t *old_code_ptr = s->code_ptr;
+
+    stack_bounds_check(arg1, arg2);
     if (type == TCG_TYPE_I32) {
         tcg_out_op_t(s, INDEX_op_st_i32);
         tcg_out_r(s, arg);
-- 
2.25.1