tcg: Define tcg_insn_unit for code pointers

To be defined by the tcg backend based on the elemental unit of the ISA.
During the transition, allow TCG_TARGET_INSN_UNIT_SIZE to be undefined,
which allows us to default tcg_insn_unit to the current uint8_t.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>

3 files changed, 100 insertions, 48 deletions

diff --git a/tcg/tcg-be-ldst.h b/tcg/tcg-be-ldst.h
index ad94c0ca51..49b3de61ea 100644
--- a/tcg/tcg-be-ldst.h
+++ b/tcg/tcg-be-ldst.h
@@ -31,8 +31,8 @@ typedef struct TCGLabelQemuLdst {
     TCGReg datalo_reg;      /* reg index for low word to be loaded or stored */
     TCGReg datahi_reg;      /* reg index for high word to be loaded or stored */
     int mem_index;          /* soft MMU memory index */
-    uint8_t *raddr;         /* gen code addr of the next IR of qemu_ld/st IR */
-    uint8_t *label_ptr[2];  /* label pointers to be updated */
+    tcg_insn_unit *raddr;   /* gen code addr of the next IR of qemu_ld/st IR */
+    tcg_insn_unit *label_ptr[2]; /* label pointers to be updated */
 } TCGLabelQemuLdst;
 
 typedef struct TCGBackendData {
diff --git a/tcg/tcg.c b/tcg/tcg.c
index 31a5d48d03..0b0be454df 100644
--- a/tcg/tcg.c
+++ b/tcg/tcg.c
@@ -65,7 +65,7 @@
 /* Forward declarations for functions declared in tcg-target.c and used here. */
 static void tcg_target_init(TCGContext *s);
 static void tcg_target_qemu_prologue(TCGContext *s);
-static void patch_reloc(uint8_t *code_ptr, int type, 
+static void patch_reloc(tcg_insn_unit *code_ptr, int type,
                         intptr_t value, intptr_t addend);
 
 /* The CIE and FDE header definitions will be common to all hosts.  */
@@ -117,55 +117,87 @@ const size_t tcg_op_defs_max = ARRAY_SIZE(tcg_op_defs);
 static TCGRegSet tcg_target_available_regs[2];
 static TCGRegSet tcg_target_call_clobber_regs;
 
+#if TCG_TARGET_INSN_UNIT_SIZE == 1
 static inline void tcg_out8(TCGContext *s, uint8_t v)
 {
     *s->code_ptr++ = v;
 }
 
-static inline void tcg_patch8(uint8_t *p, uint8_t v)
+static inline void tcg_patch8(tcg_insn_unit *p, uint8_t v)
 {
-    memcpy(p, &v, sizeof(v));
+    *p = v;
 }
+#endif
 
+#if TCG_TARGET_INSN_UNIT_SIZE <= 2
 static inline void tcg_out16(TCGContext *s, uint16_t v)
 {
-    uint8_t *p = s->code_ptr;
-    memcpy(p, &v, sizeof(v));
-    s->code_ptr = p + 2;
+    if (TCG_TARGET_INSN_UNIT_SIZE == 2) {
+        *s->code_ptr++ = v;
+    } else {
+        tcg_insn_unit *p = s->code_ptr;
+        memcpy(p, &v, sizeof(v));
+        s->code_ptr = p + (2 / TCG_TARGET_INSN_UNIT_SIZE);
+    }
 }
 
-static inline void tcg_patch16(uint8_t *p, uint16_t v)
+static inline void tcg_patch16(tcg_insn_unit *p, uint16_t v)
 {
-    memcpy(p, &v, sizeof(v));
+    if (TCG_TARGET_INSN_UNIT_SIZE == 2) {
+        *p = v;
+    } else {
+        memcpy(p, &v, sizeof(v));
+    }
 }
+#endif
 
+#if TCG_TARGET_INSN_UNIT_SIZE <= 4
 static inline void tcg_out32(TCGContext *s, uint32_t v)
 {
-    uint8_t *p = s->code_ptr;
-    memcpy(p, &v, sizeof(v));
-    s->code_ptr = p + 4;
+    if (TCG_TARGET_INSN_UNIT_SIZE == 4) {
+        *s->code_ptr++ = v;
+    } else {
+        tcg_insn_unit *p = s->code_ptr;
+        memcpy(p, &v, sizeof(v));
+        s->code_ptr = p + (4 / TCG_TARGET_INSN_UNIT_SIZE);
+    }
 }
 
-static inline void tcg_patch32(uint8_t *p, uint32_t v)
+static inline void tcg_patch32(tcg_insn_unit *p, uint32_t v)
 {
-    memcpy(p, &v, sizeof(v));
+    if (TCG_TARGET_INSN_UNIT_SIZE == 4) {
+        *p = v;
+    } else {
+        memcpy(p, &v, sizeof(v));
+    }
 }
+#endif
 
+#if TCG_TARGET_INSN_UNIT_SIZE <= 8
 static inline void tcg_out64(TCGContext *s, uint64_t v)
 {
-    uint8_t *p = s->code_ptr;
-    memcpy(p, &v, sizeof(v));
-    s->code_ptr = p + 8;
+    if (TCG_TARGET_INSN_UNIT_SIZE == 8) {
+        *s->code_ptr++ = v;
+    } else {
+        tcg_insn_unit *p = s->code_ptr;
+        memcpy(p, &v, sizeof(v));
+        s->code_ptr = p + (8 / TCG_TARGET_INSN_UNIT_SIZE);
+    }
 }
 
-static inline void tcg_patch64(uint8_t *p, uint64_t v)
+static inline void tcg_patch64(tcg_insn_unit *p, uint64_t v)
 {
-    memcpy(p, &v, sizeof(v));
+    if (TCG_TARGET_INSN_UNIT_SIZE == 8) {
+        *p = v;
+    } else {
+        memcpy(p, &v, sizeof(v));
+    }
 }
+#endif
 
 /* label relocation processing */
 
-static void tcg_out_reloc(TCGContext *s, uint8_t *code_ptr, int type,
+static void tcg_out_reloc(TCGContext *s, tcg_insn_unit *code_ptr, int type,
                           int label_index, intptr_t addend)
 {
     TCGLabel *l;
@@ -188,23 +220,20 @@ static void tcg_out_reloc(TCGContext *s, uint8_t *code_ptr, int type,
     }
 }
 
-static void tcg_out_label(TCGContext *s, int label_index, void *ptr)
+static void tcg_out_label(TCGContext *s, int label_index, tcg_insn_unit *ptr)
 {
-    TCGLabel *l;
-    TCGRelocation *r;
+    TCGLabel *l = &s->labels[label_index];
     intptr_t value = (intptr_t)ptr;
+    TCGRelocation *r;
 
-    l = &s->labels[label_index];
-    if (l->has_value) {
-        tcg_abort();
-    }
-    r = l->u.first_reloc;
-    while (r != NULL) {
+    assert(!l->has_value);
+
+    for (r = l->u.first_reloc; r != NULL; r = r->next) {
         patch_reloc(r->ptr, r->type, value, r->addend);
-        r = r->next;
     }
+
     l->has_value = 1;
-    l->u.value = value;
+    l->u.value_ptr = ptr;
 }
 
 int gen_new_label(void)
@@ -359,7 +388,7 @@ void tcg_prologue_init(TCGContext *s)
 
 #ifdef DEBUG_DISAS
     if (qemu_loglevel_mask(CPU_LOG_TB_OUT_ASM)) {
-        size_t size = s->code_ptr - s->code_buf;
+        size_t size = tcg_current_code_size(s);
         qemu_log("PROLOGUE: [size=%zu]\n", size);
         log_disas(s->code_buf, size);
         qemu_log("\n");
@@ -2538,7 +2567,8 @@ static void dump_op_count(void)
 #endif
 
 
-static inline int tcg_gen_code_common(TCGContext *s, uint8_t *gen_code_buf,
+static inline int tcg_gen_code_common(TCGContext *s,
+                                      tcg_insn_unit *gen_code_buf,
                                       long search_pc)
 {
     TCGOpcode opc;
@@ -2653,7 +2683,7 @@ static inline int tcg_gen_code_common(TCGContext *s, uint8_t *gen_code_buf,
         }
         args += def->nb_args;
     next:
-        if (search_pc >= 0 && search_pc < s->code_ptr - gen_code_buf) {
+        if (search_pc >= 0 && search_pc < tcg_current_code_size(s)) {
             return op_index;
         }
         op_index++;
@@ -2667,7 +2697,7 @@ static inline int tcg_gen_code_common(TCGContext *s, uint8_t *gen_code_buf,
     return -1;
 }
 
-int tcg_gen_code(TCGContext *s, uint8_t *gen_code_buf)
+int tcg_gen_code(TCGContext *s, tcg_insn_unit *gen_code_buf)
 {
 #ifdef CONFIG_PROFILER
     {
@@ -2686,16 +2716,17 @@ int tcg_gen_code(TCGContext *s, uint8_t *gen_code_buf)
     tcg_gen_code_common(s, gen_code_buf, -1);
 
     /* flush instruction cache */
-    flush_icache_range((uintptr_t)gen_code_buf, (uintptr_t)s->code_ptr);
+    flush_icache_range((uintptr_t)s->code_buf, (uintptr_t)s->code_ptr);
 
-    return s->code_ptr -  gen_code_buf;
+    return tcg_current_code_size(s);
 }
 
 /* Return the index of the micro operation such as the pc after is <
    offset bytes from the start of the TB.  The contents of gen_code_buf must
    not be changed, though writing the same values is ok.
    Return -1 if not found. */
-int tcg_gen_code_search_pc(TCGContext *s, uint8_t *gen_code_buf, long offset)
+int tcg_gen_code_search_pc(TCGContext *s, tcg_insn_unit *gen_code_buf,
+                           long offset)
 {
     return tcg_gen_code_common(s, gen_code_buf, offset);
 }
diff --git a/tcg/tcg.h b/tcg/tcg.h
index d38c92d636..a3fb88cd04 100644
--- a/tcg/tcg.h
+++ b/tcg/tcg.h
@@ -146,10 +146,26 @@ typedef enum TCGOpcode {
 #define tcg_regset_andnot(d, a, b) (d) = (a) & ~(b)
 #define tcg_regset_not(d, a) (d) = ~(a)
 
+#ifndef TCG_TARGET_INSN_UNIT_SIZE
+#define TCG_TARGET_INSN_UNIT_SIZE 1
+#endif
+#if TCG_TARGET_INSN_UNIT_SIZE == 1
+typedef uint8_t tcg_insn_unit;
+#elif TCG_TARGET_INSN_UNIT_SIZE == 2
+typedef uint16_t tcg_insn_unit;
+#elif TCG_TARGET_INSN_UNIT_SIZE == 4
+typedef uint32_t tcg_insn_unit;
+#elif TCG_TARGET_INSN_UNIT_SIZE == 8
+typedef uint64_t tcg_insn_unit;
+#else
+/* The port better have done this.  */
+#endif
+
+
 typedef struct TCGRelocation {
     struct TCGRelocation *next;
     int type;
-    uint8_t *ptr;
+    tcg_insn_unit *ptr;
     intptr_t addend;
 } TCGRelocation; 
 
@@ -157,6 +173,7 @@ typedef struct TCGLabel {
     int has_value;
     union {
         uintptr_t value;
+        tcg_insn_unit *value_ptr;
         TCGRelocation *first_reloc;
     } u;
 } TCGLabel;
@@ -464,7 +481,7 @@ struct TCGContext {
     int nb_temps;
 
     /* goto_tb support */
-    uint8_t *code_buf;
+    tcg_insn_unit *code_buf;
     uintptr_t *tb_next;
     uint16_t *tb_next_offset;
     uint16_t *tb_jmp_offset; /* != NULL if USE_DIRECT_JUMP */
@@ -485,7 +502,7 @@ struct TCGContext {
     intptr_t frame_end;
     int frame_reg;
 
-    uint8_t *code_ptr;
+    tcg_insn_unit *code_ptr;
     TCGTemp temps[TCG_MAX_TEMPS]; /* globals first, temps after */
     TCGTempSet free_temps[TCG_TYPE_COUNT * 2];
 
@@ -524,14 +541,17 @@ struct TCGContext {
     uint16_t gen_opc_icount[OPC_BUF_SIZE];
     uint8_t gen_opc_instr_start[OPC_BUF_SIZE];
 
-    /* Code generation */
+    /* Code generation.  Note that we specifically do not use tcg_insn_unit
+       here, because there's too much arithmetic throughout that relies
+       on addition and subtraction working on bytes.  Rely on the GCC
+       extension that allows arithmetic on void*.  */
     int code_gen_max_blocks;
-    uint8_t *code_gen_prologue;
-    uint8_t *code_gen_buffer;
+    void *code_gen_prologue;
+    void *code_gen_buffer;
     size_t code_gen_buffer_size;
     /* threshold to flush the translated code buffer */
     size_t code_gen_buffer_max_size;
-    uint8_t *code_gen_ptr;
+    void *code_gen_ptr;
 
     TBContext tb_ctx;
 
@@ -566,8 +586,9 @@ void tcg_context_init(TCGContext *s);
 void tcg_prologue_init(TCGContext *s);
 void tcg_func_start(TCGContext *s);
 
-int tcg_gen_code(TCGContext *s, uint8_t *gen_code_buf);
-int tcg_gen_code_search_pc(TCGContext *s, uint8_t *gen_code_buf, long offset);
+int tcg_gen_code(TCGContext *s, tcg_insn_unit *gen_code_buf);
+int tcg_gen_code_search_pc(TCGContext *s, tcg_insn_unit *gen_code_buf,
+                           long offset);
 
 void tcg_set_frame(TCGContext *s, int reg, intptr_t start, intptr_t size);