freedreno/afuc: Add support for multiple sections when assembling

Sections have names that are currently unused but we will need to use
them on a750 for relocations.

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

src/freedreno/afuc/asm.c

@@ -93,11 +93,14 @@ static unsigned instr_offset;
 static struct asm_label labels[0x512];
 static unsigned num_labels;
 
+static int outfd;
+
 struct afuc_instr *
 next_instr(afuc_opc opc)
 {
    struct afuc_instr *ai = &instructions[num_instructions++];
    assert(num_instructions < ARRAY_SIZE(instructions));
+   memset(ai, 0, sizeof(*ai));
    instr_offset++;
    ai->opc = opc;
    return ai;
@@ -181,12 +184,6 @@ emit_instructions(int outfd)
       .gen = gpuver,
    };
 
-   /* there is an extra 0x00000000 which kernel strips off.. we could
-    * perhaps use it for versioning.
-    */
-   i = 0;
-   write(outfd, &i, 4);
-
    /* Expand some meta opcodes, and resolve branch targets */
    for (i = 0; i < num_instructions; i++) {
       struct afuc_instr *ai = &instructions[i];
@@ -247,6 +244,19 @@ emit_instructions(int outfd)
    }
 }
 
+void next_section(void)
+{
+   /* Sections must be aligned to 32 bytes */
+   align_instr(32);
+
+   emit_instructions(outfd);
+
+   num_instructions = 0;
+   instr_offset = 0;
+   num_labels = 0;
+}
+
+
 unsigned
 parse_control_reg(const char *name)
 {
@@ -275,7 +285,7 @@ main(int argc, char **argv)
 {
    FILE *in;
    char *file, *outfile;
-   int c, ret, outfd;
+   int c, ret;
 
    /* Argument parsing: */
    while ((c = getopt(argc, argv, "g:")) != -1) {
@@ -326,6 +336,12 @@ main(int argc, char **argv)
       usage();
    }
 
+   /* there is an extra 0x00000000 which kernel strips off.. we could
+    * perhaps use it for versioning.
+    */
+   uint32_t zero = 0;
+   write(outfd, &zero, 4);
+
    ret = yyparse();
    if (ret) {
       fprintf(stderr, "parse failed: %d\n", ret);

src/freedreno/afuc/asm.h

@@ -39,6 +39,7 @@ struct afuc_instr *next_instr(afuc_opc opc);
 void decl_label(const char *str);
 void decl_jumptbl(void);
 void align_instr(unsigned alignment);
+void next_section(void);
 
 static inline uint32_t
 parse_reg(const char *str)

src/freedreno/afuc/disasm.c

@@ -353,6 +353,7 @@ disasm(struct emu *emu)
    }
 
    if (bv_offset) {
+      printf("\n.section BV\n");
       printf(";\n");
       printf("; BV microcode:\n");
       printf(";\n");
@@ -390,6 +391,7 @@ disasm(struct emu *emu)
    }
 
    if (lpac_offset) {
+      printf("\n.section LPAC\n");
       printf(";\n");
       printf("; LPAC microcode:\n");
       printf(";\n");

src/freedreno/afuc/lexer.l

@@ -99,6 +99,7 @@ extern YYSTYPE yylval;
 
 ".align"                          return TOKEN(T_ALIGN);
 ".jumptbl"                        return TOKEN(T_JUMPTBL);
+".section"                        return TOKEN(T_SECTION);
 
 ","                               return ',';
 "["                               return '[';

src/freedreno/afuc/parser.y

@@ -175,6 +175,7 @@ label(const char *str)
 
 %token <tok> T_ALIGN
 %token <tok> T_JUMPTBL
+%token <tok> T_SECTION
 
 %type <num> reg
 %type <num> immediate
@@ -197,6 +198,7 @@ instr_or_label:    instr_r
 |                  T_IDENTIFIER ':'    { decl_label($1); }
 |                  T_ALIGN immediate   { align_instr($2); }
 |                  T_JUMPTBL           { decl_jumptbl(); }
+|                  T_SECTION T_IDENTIFIER { next_section(); }
 
 xmov:              T_XMOV { $$ = $1; }
 |                  { $$ = 0; }