agx: Track block offsets

For fixing branch offsets.

Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/11023>

src/asahi/compiler/agx_compiler.h

@@ -303,6 +303,9 @@ typedef struct agx_block {
    /* Liveness analysis results */
    BITSET_WORD *live_in;
    BITSET_WORD *live_out;
+
+   /* Offset of the block in the emitted binary */
+   off_t offset;
 } agx_block;
 
 typedef struct {

src/asahi/compiler/agx_pack.c

@@ -552,6 +552,13 @@ agx_pack_instr(struct util_dynarray *emission, agx_instr *I)
 void
 agx_pack(agx_context *ctx, struct util_dynarray *emission)
 {
-   agx_foreach_instr_global(ctx, ins)
-      agx_pack_instr(emission, ins);
+   agx_foreach_block(ctx, block) {
+      /* Relative to the start of the binary, the block begins at the current
+       * number of bytes emitted */
+      block->offset = emission->size;
+
+      agx_foreach_instr_in_block(block, ins) {
+         agx_pack_instr(emission, ins);
+      }
+   }
 }