117 lines
3.8 KiB
C
117 lines
3.8 KiB
C
#ifndef SCRATCH_H
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#define SCRATCH_H
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#include "arena.h"
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#include "sys.h"
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#include "thread_local.h"
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#define SCRATCH_ARENAS_PER_THREAD 2
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#define SCRATCH_ARENA_RESERVE (GIGABYTE(64))
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/* ========================== *
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* Thread local state
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* ========================== */
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struct scratch_ctx {
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struct arena *arenas[SCRATCH_ARENAS_PER_THREAD];
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#if RTC
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u64 next_scratch_id;
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u64 scratch_id_stack[16384];
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u64 scratch_id_stack_count;
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#endif
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};
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THREAD_LOCAL_VAR_DECL_EXTERN(tl_scratch_ctx, struct scratch_ctx);
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/* ========================== *
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* Scratch begin
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* ========================== */
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INLINE void scratch_dbg_push(struct scratch_ctx *ctx, struct arena_temp *temp)
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{
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#if RTC
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if (ctx->scratch_id_stack_count >= ARRAY_COUNT(ctx->scratch_id_stack)) {
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sys_panic(LIT("Max debug scratch depth reached"));
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}
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temp->scratch_id = ctx->next_scratch_id++;
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ctx->scratch_id_stack[ctx->scratch_id_stack_count++] = temp->scratch_id;
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#else
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(UNUSED)ctx;
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(UNUSED)temp;
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#endif
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}
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/* Any parameterized arenas in the caller's scope should be passed into this
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* function as a potential "conflict". This is to prevent friction in case the
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* passed arena is itself a scratch arena from another scope (since
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* parameterized arenas are often used to allocate persistent results for the
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* caller).
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*
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* Use `scratch_begin_no_conflict` instead if there is no arena in the current
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* scope that could potentially be a scratch arena from another scope. */
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#define scratch_begin(potential_conflict) _scratch_begin(potential_conflict)
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INLINE struct arena_temp _scratch_begin(struct arena *potential_conflict)
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{
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/* This function is currently hard-coded to support 2 scratch arenas */
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CT_ASSERT(SCRATCH_ARENAS_PER_THREAD == 2);
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/* Use `scratch_begin_no_conflict` if no conflicts are present */
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ASSERT(potential_conflict != NULL);
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struct scratch_ctx *ctx = (struct scratch_ctx *)thread_local_var_eval(&tl_scratch_ctx);
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struct arena *scratch_arena = ctx->arenas[0];
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if (potential_conflict && scratch_arena == potential_conflict) {
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scratch_arena = ctx->arenas[1];
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}
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struct arena_temp temp = arena_temp_begin(scratch_arena);
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scratch_dbg_push(ctx, &temp);
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return temp;
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}
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/* This macro declares an unused "arena" variable that will error if an existing "arena"
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* variable is present (due to shadowing). This is for catching obvious cases of
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* `scratch_begin_no_conflict` getting called when an `arena` variable already
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* exists in the caller's scope (`scratch_begin(arena)` should be called
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* instead). */
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#define scratch_begin_no_conflict() \
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_scratch_begin_no_conflict(); \
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do { \
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u8 arena = 0; \
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(UNUSED)arena; \
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} while (0)
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INLINE struct arena_temp _scratch_begin_no_conflict(void)
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{
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struct scratch_ctx *ctx = (struct scratch_ctx *)thread_local_var_eval(&tl_scratch_ctx);
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struct arena *scratch_arena = ctx->arenas[0];
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struct arena_temp temp = arena_temp_begin(scratch_arena);
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scratch_dbg_push(ctx, &temp);
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return temp;
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}
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/* ========================== *
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* Scratch end
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* ========================== */
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INLINE void scratch_end(struct arena_temp scratch_temp)
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{
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#if RTC
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struct scratch_ctx *ctx = (struct scratch_ctx *)thread_local_var_eval(&tl_scratch_ctx);
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if (ctx->scratch_id_stack_count > 0) {
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u64 scratch_id = scratch_temp.scratch_id;
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u64 expected_id = ctx->scratch_id_stack[--ctx->scratch_id_stack_count];
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/* This assertion exists to catch cases where a scratch_end was forgotten.
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* It will fail if a scratch arena is reset out of order.
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* E.g. there is a missing scratch_end somewhere on a different scratch
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* arena (one that was created between the scratch_begin & the
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* scratch_end of the arena being reset here). */
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ASSERT(scratch_id == expected_id);
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}
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#endif
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arena_temp_end(scratch_temp);
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}
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#endif
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