freedreno/afuc: Add .align directive

This will be necessary for aligning the sections.

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/26771>

src/freedreno/afuc/asm.c

@@ -123,6 +123,14 @@ decl_jumptbl(void)
    instr_offset += 0x80;
 }
 
+void
+align_instr(unsigned alignment)
+{
+   while (instr_offset % (alignment / 4) != 0) {
+      next_instr(OPC_NOP);
+   }
+}
+
 static int
 resolve_label(const char *str)
 {

src/freedreno/afuc/asm.h

@@ -38,6 +38,7 @@ struct asm_label {
 struct afuc_instr *next_instr(afuc_opc opc);
 void decl_label(const char *str);
 void decl_jumptbl(void);
+void align_instr(unsigned alignment);
 
 static inline uint32_t
 parse_reg(const char *str)

src/freedreno/afuc/disasm.c

@@ -334,6 +334,15 @@ disasm(struct emu *emu)
 
    /* print jump table */
    if (jumptbl_offset != ~0) {
+      if (gpuver >= 7) {
+         /* The BV/LPAC microcode must be aligned to 32 bytes. On a7xx, by
+          * convention the firmware aligns the jumptable preceding it instead
+          * of the microcode itself, with nop instructions. Insert this
+          * directive to make sure that it stays aligned when reassembling
+          * even if the user modifies the BR microcode.
+          */
+         printf(".align 32\n");
+      }
       printf("jumptbl:\n");
       printf(".jumptbl\n");
 
@@ -367,6 +376,7 @@ disasm(struct emu *emu)
       isa_disasm(emu->instrs, MIN2(sizedwords, jumptbl_offset) * 4, stdout, &options);
 
       if (jumptbl_offset != ~0) {
+         printf(".align 32\n");
          printf("jumptbl:\n");
          printf(".jumptbl\n");
          if (jumptbl_offset + ARRAY_SIZE(emu->jmptbl) != sizedwords) {

src/freedreno/afuc/lexer.l

@@ -98,6 +98,7 @@ extern YYSTYPE yylval;
 "(sds"[1-3]")"                    yylval.num = yytext[4] - '0'; return T_SDS;
 "(peek)"                          return TOKEN(T_PEEK);
 
+".align"                          return TOKEN(T_ALIGN);
 ".jumptbl"                        return TOKEN(T_JUMPTBL);
 
 ","                               return ',';

src/freedreno/afuc/parser.y

@@ -173,6 +173,7 @@ label(const char *str)
 %token <num> T_XMOV
 %token <num> T_SDS
 
+%token <tok> T_ALIGN
 %token <tok> T_JUMPTBL
 
 %type <num> reg
@@ -194,6 +195,7 @@ instr_or_label:    instr_r
 |                  branch_instr
 |                  other_instr
 |                  T_LABEL_DECL        { decl_label($1); }
+|                  T_ALIGN immediate   { align_instr($2); }
 |                  T_JUMPTBL           { decl_jumptbl(); }
 
 xmov:              T_XMOV { $$ = $1; }