From d4db0b8a082385c793d03c9e0ab4423c10821945 Mon Sep 17 00:00:00 2001
From: Andrea Shepard <andrea@persephoneslair.org>
Date: Mon, 21 Nov 2016 01:35:53 +0000
Subject: [PATCH] Split LLVM charset code out into llvm_charset.c
---
src/SConscript | 2 +-
src/backends/llvm/llvm.c | 843 ------------------------------
src/backends/llvm/llvm_charset.c | 855 +++++++++++++++++++++++++++++++
3 files changed, 856 insertions(+), 844 deletions(-)
create mode 100644 src/backends/llvm/llvm_charset.c
diff --git a/src/SConscript b/src/SConscript
index 1495f42b..2903ec72 100644
--- a/src/SConscript
+++ b/src/SConscript
@@ -70,7 +70,7 @@ backends = ['backends/%s.c' % s for s in
# Add LLVM backend if enabled
if GetOption("use_llvm"):
- llvm_backend_files = ['llvm.c']
+ llvm_backend_files = ['llvm.c', 'llvm_charset.c']
backends = backends + ['backends/llvm/%s' % s for s in llvm_backend_files]
misc_hammer_parts = [
diff --git a/src/backends/llvm/llvm.c b/src/backends/llvm/llvm.c
index 7af7d08a..e393b0e7 100644
--- a/src/backends/llvm/llvm.c
+++ b/src/backends/llvm/llvm.c
@@ -147,849 +147,6 @@ void h_llvm_free(HParser *parser) {
llvm_parser->mod = NULL;
}
-typedef enum {
- /*
- * Accept action; this entire range is in the charset. This action type
- * has no children and terminates handling the input character.
- */
- CHARSET_ACTION_ACCEPT,
- /*
- * Scan action; test input char against each set character in the charset.
- * This action type has no children and terminates handling the input
- * character.
- */
- CHARSET_ACTION_SCAN,
- /*
- * Bitmap action; test input char against a bitmap in the IR at fixed
- * cost.
- */
- CHARSET_ACTION_BITMAP,
- /*
- * Complement action; invert the sense of the charset. This action type
- * has one child node, with the bounds unchanged and the portion of the
- * charset within the bounds complemented.
- */
- CHARSET_ACTION_COMPLEMENT,
- /*
- * Split action; check whether the input char is above or below a split
- * point, and branch into one of two children depending.
- */
- CHARSET_ACTION_SPLIT
-} llvm_charset_exec_plan_action_t;
-
-typedef struct llvm_charset_exec_plan_s llvm_charset_exec_plan_t;
-struct llvm_charset_exec_plan_s {
- /*
- * The charset at this node, with transforms such as range restriction
- * or complementation applied.
- */
- HCharset cs;
- /*
- * Char values for the range of this node, and the split point if this
- * is CHARSET_ACTION_SPLIT
- */
- uint8_t idx_start, idx_end, split_point;
- /* Action to take at this node */
- llvm_charset_exec_plan_action_t action;
- /* Estimated cost metric */
- int cost;
- /* Depth in exec plan */
- int depth;
- /* Children, if any (zero, one or two depending on action) */
- llvm_charset_exec_plan_t *children[2];
-};
-
-/* Forward prototypes for charset llvm stuff */
-static int h_llvm_build_charset_exec_plan_impl(HAllocator* mm__, HCharset cs,
- llvm_charset_exec_plan_t *parent, llvm_charset_exec_plan_t *cep,
- int allow_complement, uint8_t *split_point);
-static llvm_charset_exec_plan_t * h_llvm_build_charset_exec_plan_impl_alloc(
- HAllocator* mm__, llvm_charset_exec_plan_t *parent, HCharset cs,
- uint8_t idx_start, uint8_t idx_end, int allow_complement);
-static void h_llvm_free_charset_exec_plan(HAllocator* mm__,
- llvm_charset_exec_plan_t *cep);
-
-/*
- * Check if this charset is eligible for CHARSET_ACTION_ACCEPT on a range
- */
-
-static int h_llvm_charset_eligible_for_accept(HCharset cs, uint8_t idx_start, uint8_t idx_end) {
- int eligible = 1, i;
-
- for (i = idx_start; i <= idx_end; ++i) {
- if (!(charset_isset(cs, (uint8_t)i))) {
- eligible = 0;
- break;
- }
- }
-
- return eligible;
-}
-
-/*
- * Estimate cost of CHARSET_ACTION_SCAN for this charset (~proportional to number of set chars, min 1)
- */
-
-static int h_llvm_charset_estimate_scan_cost(HCharset cs, uint8_t idx_start, uint8_t idx_end) {
- int i, cost;
-
- cost = 1;
- for (i = idx_start; i <= idx_end; ++i) {
- if (charset_isset(cs, (uint8_t)i)) ++cost;
- }
-
- return cost;
-}
-
-/*
- * Given a skeletal CHARSET_ACTION_SPLIT node from h_llvm_build_charset_exec_plan_impl(),
- * binary search for the best split point we can find and return the cost metric.
- * Unfortunately the search space is quite large, so we're going to use some silly
- * heuristics here such as looking for the longest run of present or absent chars at
- * one end of a charset, and proposing it as a split, or just trying the midpoint.
- * It may be possible to do better.
- */
-
-static int h_llvm_find_best_split(HAllocator* mm__, llvm_charset_exec_plan_t *split) {
- int rv, best_end_run, i, contiguous;
- uint8_t best_end_run_split, midpoint;
- llvm_charset_exec_plan_t *best_left, *best_right, *left, *right;
- int best_cost, cost;
-
- /* Sanity-check: we should be a split with a range at least two indices long */
- if (!split || split->action != CHARSET_ACTION_SPLIT) return -1;
- if (split->idx_end <= split->idx_start) return -1;
-
- /* Find the longest end run; split a run of length 1 at the left end as a
- * fallback, since there's always a run of length 1 at each end. */
- best_end_run = 1;
- best_end_run_split = split->idx_start;
- contiguous = 0;
- /* Try the low end */
- i = 0;
- while (i <= split->idx_end - split->idx_start &&
- (charset_isset(split->cs, split->idx_start + i) ==
- charset_isset(split->cs, split->idx_start))) ++i;
- if (i <= split->idx_end - split->idx_start) {
- /* This run has length i */
- if (i > best_end_run) {
- best_end_run = i;
- /*
- * -1 since split points are last index of left child, and i
- * is first index that wasn't in the run
- */
- best_end_run_split = split->idx_start + i - 1;
- }
-
- /* Now the same thing from the high end */
- i = 0;
- while (i <= split->idx_end - split->idx_start &&
- (charset_isset(split->cs, split->idx_end - i) ==
- charset_isset(split->cs, split->idx_end))) ++i;
- if (i <= split->idx_end - split->idx_start && i > best_end_run) {
- best_end_run = i;
- best_end_run_split = split->idx_end - i;
- }
- } else {
- /* Wow, contiguous - any split will turn out well - just use the midpoint */
- contiguous = 1;
- }
-
- /* Initialize, start trying things */
- best_left = best_right = left = right = NULL;
- rv = -1;
-
- /* Try a midpoint split */
- midpoint = split->idx_start + (split->idx_end - split->idx_start) / 2;
- left = h_llvm_build_charset_exec_plan_impl_alloc(mm__, split, split->cs,
- split->idx_start, midpoint, 1);
- right = h_llvm_build_charset_exec_plan_impl_alloc(mm__, split, split->cs,
- midpoint + 1, split->idx_end, 1);
- if (left && right) {
- /* Cost of the split == 1 + max(left->cost, right->cost) */
- cost = left->cost;
- if (right->cost > cost) cost = right->cost;
- ++cost;
- /* We haven't tried the end-run one yet, so always accept this */
- best_left = left;
- best_right = right;
- best_cost = cost;
- left = right = NULL;
- } else goto err;
-
- /*
- * Try an end-run split; if we decided we had a contiguous run earlier,
- * all are equally good, so don't bother and just use the midpoint
- */
-
- if (!contiguous) {
- /*
- * Sanity-check the indices; error out if the scanner gave us
- * something silly
- */
- if (best_end_run_split < split->idx_start ||
- best_end_run_split >= split->idx_end) goto err;
- left = h_llvm_build_charset_exec_plan_impl_alloc(mm__, split, split->cs,
- split->idx_start, best_end_run_split, 1);
- right = h_llvm_build_charset_exec_plan_impl_alloc(mm__, split, split->cs,
- best_end_run_split + 1, split->idx_end, 1);
- if (left && right) {
- /* Cost of the split == 1 + max(left->cost, right->cost) */
- cost = left->cost;
- if (right->cost > cost) cost = right->cost;
- ++cost;
- /* Check if against what we already have */
- if (cost < best_cost) {
- if (best_left) h_llvm_free_charset_exec_plan(mm__, best_left);
- if (best_right) h_llvm_free_charset_exec_plan(mm__, best_right);
- best_left = left;
- best_right = right;
- best_cost = cost;
- left = right = NULL;
- }
- } else goto err;
- }
-
- /* Set up the split node with our best results */
- split->cost = best_cost;
- split->children[0] = best_left;
- split->children[1] = best_right;
- split->split_point = best_left->idx_end;
- best_left = best_right = NULL;
- rv = split->cost;
-
- err:
- /* Error/cleanup case */
- if (left) h_llvm_free_charset_exec_plan(mm__, left);
- if (right) h_llvm_free_charset_exec_plan(mm__, right);
- if (best_left) h_llvm_free_charset_exec_plan(mm__, best_left);
- if (best_right) h_llvm_free_charset_exec_plan(mm__, best_right);
-
- return rv;
-}
-
-/*
- * Setup call to h_llvm_build_charset_exec_plan_impl(), while allocating a new
- * llvm_charset_exec_plan_t.
- */
-static llvm_charset_exec_plan_t * h_llvm_build_charset_exec_plan_impl_alloc(
- HAllocator* mm__, llvm_charset_exec_plan_t *parent, HCharset cs,
- uint8_t idx_start, uint8_t idx_end, int allow_complement) {
- int cost;
- llvm_charset_exec_plan_t *cep;
-
- if (!mm__) return NULL;
- if (!cs) return NULL;
- if (idx_start > idx_end) return NULL;
-
- cep = h_new(llvm_charset_exec_plan_t, 1);
- memset(cep, 0, sizeof(*cep));
- cep->cs = NULL;
- /*
- * Initializing these is important; if the parent is CHARSET_ACTION_SPLIT,
- * these are how h_llvm_build_charset_exec_plan_impl() knows the range for
- * the child it's constructing.
- */
- cep->idx_start = idx_start;
- cep->idx_end = idx_end;
- cost = h_llvm_build_charset_exec_plan_impl(mm__, cs, parent, cep,
- allow_complement, NULL);
- if (cost >= 0) cep->cost = cost;
- else {
- h_llvm_free_charset_exec_plan(mm__, cep);
- cep = NULL;
- }
-
- return cep;
-}
-
-/*
- * Given a charset, optionally its parent containing range restrictions, and
- * an allow_complement parameter, search for the best exec plan and write it
- * to another (skeletal) charset which will receive an action and range. If
- * the action is CHARSET_ACTION_SPLIT, also output a split point. Return a
- * cost estimate.
- */
-
-static int h_llvm_build_charset_exec_plan_impl(HAllocator* mm__, HCharset cs,
- llvm_charset_exec_plan_t *parent, llvm_charset_exec_plan_t *cep,
- int allow_complement, uint8_t *split_point) {
- int eligible_for_accept, best_cost, depth;
- int estimated_complement_cost, estimated_scan_cost, estimated_split_cost;
- int estimated_bitmap_cost;
- uint8_t idx_start, idx_end;
- llvm_charset_exec_plan_t complement_cep, split_cep;
- llvm_charset_exec_plan_action_t chosen_action;
-
- /* Check args */
- if (!(mm__ && cep)) return -1;
-
- /*
- * The index bounds come from either the parent or maximal bounds by
- * default. Exception is the case that we are a child of a split, in
- * which case h_llvm_find_best_split() should have set bounds in cep.
- */
- if (parent && parent->action == CHARSET_ACTION_SPLIT &&
- ((cep->idx_start == parent->idx_start &&
- cep->idx_end < parent->idx_end) ||
- (cep->idx_start > parent->idx_start &&
- cep->idx_end == parent->idx_end))) {
- idx_start = cep->idx_start;
- idx_end = cep->idx_end;
- } else if (parent) {
- idx_start = parent->idx_start;
- idx_end = parent->idx_end;
- } else {
- idx_start = 0;
- idx_end = UINT8_MAX;
- }
-
- /* Get the depth in the exec plan */
- if (parent) depth = parent->depth + 1;
- else depth = 0;
-
- eligible_for_accept = h_llvm_charset_eligible_for_accept(cs, idx_start, idx_end);
- if (eligible_for_accept) {
- /* if we can use CHARSET_ACTION_ACCEPT, always do so */
- cep->cs = copy_charset(mm__, cs);
- charset_restrict_to_range(cep->cs, idx_start, idx_end);
- cep->idx_start = idx_start;
- cep->idx_end = idx_end;
- cep->split_point = 0;
- /* Acceptance (or rejection, under a complement) is free */
- cep->cost = 0;
- cep->depth = depth;
- cep->action = CHARSET_ACTION_ACCEPT;
- cep->children[0] = NULL;
- cep->children[1] = NULL;
-
- return cep->cost;
- } else {
- /*
- * Estimate cost for CHARSET_ACTION_SCAN, and for the tree below
- * CHARSET_ACTION_COMPLEMENT if we are eligible to use it.
- */
- estimated_scan_cost = h_llvm_charset_estimate_scan_cost(cs, idx_start, idx_end);
- /*
- * We can always use CHARSET_ACTION_BITMAP; this constant controls how
- * strongly we prefer it over the compare-and-branch approach.
- */
- estimated_bitmap_cost = 6;
- /* >= 0 is a flag we have a complement we may need to free later */
- estimated_complement_cost = -1;
- if (allow_complement) {
- HCharset child_cs;
-
- /* Complement the charset within the range */
- memset(&complement_cep, 0, sizeof(complement_cep));
- complement_cep.cs = copy_charset(mm__, cs);
- charset_restrict_to_range(complement_cep.cs, idx_start, idx_end);
- child_cs = copy_charset(mm__, complement_cep.cs);
- charset_complement(child_cs);
- charset_restrict_to_range(child_cs, idx_start, idx_end);
- complement_cep.idx_start = idx_start;
- complement_cep.idx_end = idx_end;
- complement_cep.split_point = 0;
- complement_cep.depth = depth;
- complement_cep.action = CHARSET_ACTION_COMPLEMENT;
- complement_cep.children[0] = h_new(llvm_charset_exec_plan_t, 1);
- memset(complement_cep.children[0], 0, sizeof(llvm_charset_exec_plan_t));
- complement_cep.children[1] = NULL;
- /*
- * Find the child; the complement has cost 0 since it just swizzles success
- * and fail output basic blocks; it's important we test for complement last
- * below then, so we break ties in favor of not stacking complements up. We
- * set allow_complement = 0 so we never stack two complements.
- */
- complement_cep.cost = h_llvm_build_charset_exec_plan_impl(mm__, child_cs, &complement_cep,
- complement_cep.children[0], 0, NULL);
- estimated_complement_cost = complement_cep.cost;
- h_free(child_cs);
- }
-
- /*
- * Set up split node if it makes sense; the depth cutoff here limits the
- * cost of the search for complex charsets.
- */
- if (idx_start < idx_end && depth < 5) {
- split_cep.cs = copy_charset(mm__, cs);
- charset_restrict_to_range(split_cep.cs, idx_start, idx_end);
- split_cep.idx_start = idx_start;
- split_cep.idx_end = idx_end;
- split_cep.split_point = 0;
- split_cep.action = CHARSET_ACTION_SPLIT;
- split_cep.cost = -1;
- split_cep.depth = depth;
- split_cep.children[0] = NULL;
- split_cep.children[1] = NULL;
- /* h_llvm_find_best_split() sets split_cep.cost */
- estimated_split_cost = h_llvm_find_best_split(mm__, &split_cep);
- if (estimated_split_cost < 0) {
- /* This shouldn't happen, but make sure we free the charset */
- h_free(split_cep.cs);
- }
- } else {
- estimated_split_cost = -1;
- }
-
- /* Pick the action type with the lowest cost */
- best_cost = -1;
- if (estimated_scan_cost >= 0 &&
- (best_cost < 0 || estimated_scan_cost < best_cost)) {
- chosen_action = CHARSET_ACTION_SCAN;
- best_cost = estimated_scan_cost;
- }
-
- if (estimated_bitmap_cost >= 0 &&
- (best_cost < 0 || estimated_bitmap_cost < best_cost)) {
- chosen_action = CHARSET_ACTION_BITMAP;
- best_cost = estimated_bitmap_cost;
- }
-
- if (estimated_split_cost >= 0 &&
- (best_cost < 0 || estimated_split_cost < best_cost)) {
- chosen_action = CHARSET_ACTION_SPLIT;
- best_cost = estimated_split_cost;
- }
-
- if (allow_complement && estimated_complement_cost >= 0 &&
- (best_cost < 0 || estimated_complement_cost < best_cost)) {
- chosen_action = CHARSET_ACTION_COMPLEMENT;
- best_cost = estimated_complement_cost;
- }
-
- /* Fill out cep based on the chosen action */
- switch (chosen_action) {
- case CHARSET_ACTION_SCAN:
- /* Set up a scan */
- cep->cs = copy_charset(mm__, cs);
- charset_restrict_to_range(cep->cs, idx_start, idx_end);
- cep->idx_start = idx_start;
- cep->idx_end = idx_end;
- cep->split_point = 0;
- cep->action = CHARSET_ACTION_SCAN;
- cep->cost = estimated_scan_cost;
- cep->depth = depth;
- cep->children[0] = NULL;
- cep->children[1] = NULL;
- break;
- case CHARSET_ACTION_BITMAP:
- /* Set up a bitmap */
- cep->cs = copy_charset(mm__, cs);
- charset_restrict_to_range(cep->cs, idx_start, idx_end);
- cep->idx_start = idx_start;
- cep->idx_end = idx_end;
- cep->split_point = 0;
- cep->action = CHARSET_ACTION_BITMAP;
- cep->cost = estimated_bitmap_cost;
- cep->depth = depth;
- cep->children[0] = NULL;
- cep->children[1] = NULL;
- break;
- case CHARSET_ACTION_COMPLEMENT:
- /*
- * We have a CEP filled out we can just copy over; be sure to set
- * estimated_complement_cost = -1 so we know not to free it on the
- * way out.
- */
- memcpy(cep, &complement_cep, sizeof(complement_cep));
- memset(&complement_cep, 0, sizeof(complement_cep));
- estimated_complement_cost = -1;
- break;
- case CHARSET_ACTION_SPLIT:
- /*
- * We have a CEP filled out we can just copy over; be sure to set
- * estimated_split_cost = -1 so we know not to free it on the way
- * out.
- */
- memcpy(cep, &split_cep, sizeof(split_cep));
- memset(&split_cep, 0, sizeof(split_cep));
- estimated_split_cost = -1;
- break;
- default:
- /* Not supported */
- best_cost = -1;
- memset(cep, 0, sizeof(*cep));
- break;
- }
- }
-
- /* Free temporary CEPs if needed */
-
- if (estimated_complement_cost >= 0) {
- /*
- * We have a complement_cep we ended up not using; free its child and
- * charset
- */
- h_llvm_free_charset_exec_plan(mm__, complement_cep.children[0]);
- h_free(complement_cep.cs);
- memset(&complement_cep, 0, sizeof(complement_cep));
- estimated_complement_cost = -1;
- }
-
- if (estimated_split_cost >= 0) {
- /*
- * We have a split_cep we ended up not using; free its children and
- * charset.
- */
- h_llvm_free_charset_exec_plan(mm__, split_cep.children[0]);
- h_llvm_free_charset_exec_plan(mm__, split_cep.children[1]);
- h_free(split_cep.cs);
- memset(&split_cep, 0, sizeof(split_cep));
- estimated_split_cost = -1;
- }
-
- return best_cost;
-}
-
-/*
- * Build a charset exec plan for a charset
- */
-
-static llvm_charset_exec_plan_t * h_llvm_build_charset_exec_plan(
- HAllocator* mm__, HCharset cs) {
- llvm_charset_exec_plan_t *cep = NULL;
- int best_cost;
-
- cep = h_new(llvm_charset_exec_plan_t, 1);
- best_cost = h_llvm_build_charset_exec_plan_impl(mm__, cs, NULL, cep, 1, NULL);
-
- if (best_cost < 0) {
- /* h_llvm_build_charset_exec_plan_impl() failed */
- h_free(cep);
- cep = NULL;
- }
-
- return cep;
-}
-
-/*
- * Consistency-check a charset exec plan
- */
-
-static bool h_llvm_check_charset_exec_plan(llvm_charset_exec_plan_t *cep) {
- bool consistent = false;
- uint8_t i;
-
- if (cep) {
- /* Check that we have a charset */
- if (!(cep->cs)) goto done;
- /* Check that the range makes sense */
- if (cep->idx_start > cep->idx_end) goto done;
- /* Check that the charset is empty outside the range */
- for (i = 0; i < cep->idx_start; ++i) {
- /* Failed check */
- if (charset_isset(cep->cs, i)) goto done;
- /* Prevent wraparound */
- if (i == UINT8_MAX) break;
- }
-
- if (cep->idx_end < UINT8_MAX) {
- /* We break at the end */
- for (i = cep->idx_end + 1; ; ++i) {
- /* Failed check */
- if (charset_isset(cep->cs, i)) goto done;
- /* Prevent wraparound */
- if (i == UINT8_MAX) break;
- }
- }
-
- /* Minimum cost estimate is 0; complements and accepts can be free */
- if (cep->cost < 0) goto done;
-
- /* No split point unlesswe're CHARSET_ACTION_SPLIT */
- if (cep->action != CHARSET_ACTION_SPLIT && cep->split_point != 0) goto done;
-
- /* Action type dependent part */
- switch (cep->action) {
- case CHARSET_ACTION_ACCEPT:
- case CHARSET_ACTION_SCAN:
- case CHARSET_ACTION_BITMAP:
- /* These are always okay and have no children */
- if (cep->children[0] || cep->children[1]) goto done;
- consistent = true;
- break;
- case CHARSET_ACTION_COMPLEMENT:
- /* This has one child, which should have the same range */
- if (cep->children[1]) goto done;
- if (cep->children[0]) {
- if (cep->children[0]->idx_start == cep->idx_start &&
- cep->children[0]->idx_end == cep->idx_end) {
- /* The cost cannot be lower than the child */
- if (cep->cost < cep->children[0]->cost) goto done;
- /* Okay, we're consistent if the child node is */
- consistent = h_llvm_check_charset_exec_plan(cep->children[0]);
- }
- }
- break;
- case CHARSET_ACTION_SPLIT:
- /* This has two children, which should split the range */
- if (cep->children[0] && cep->children[1]) {
- if (cep->children[0]->idx_start == cep->idx_start &&
- cep->children[0]->idx_end + 1 == cep->children[1]->idx_start &&
- cep->children[1]->idx_end == cep->idx_end) {
- /* The split point must match the children */
- if (cep->split_point != cep->children[0]->idx_end) goto done;
- /*
- * The cost must be in the range defined by the children, + 1 for
- * the comparison at most
- */
- int child_min_cost = (cep->children[0]->cost < cep->children[1]->cost) ?
- cep->children[0]->cost : cep->children[1]->cost;
- int child_max_cost = (cep->children[0]->cost > cep->children[1]->cost) ?
- cep->children[0]->cost : cep->children[1]->cost;
- if ((cep->cost < child_min_cost) || (cep->cost > child_max_cost + 1)) goto done;
- /* Okay, we're consistent if both children are */
- consistent = h_llvm_check_charset_exec_plan(cep->children[0]) &&
- h_llvm_check_charset_exec_plan(cep->children[1]);
- }
- }
- break;
- default:
- break;
- }
- }
-
- done:
- return consistent;
-}
-
-/*
- * Free a charset exec plan using the supplied allocator
- */
-
-static void h_llvm_free_charset_exec_plan(HAllocator* mm__,
- llvm_charset_exec_plan_t *cep) {
- int n_children, i;
-
- if (cep) {
- n_children = 0;
- switch (cep->action) {
- case CHARSET_ACTION_COMPLEMENT:
- n_children = 1;
- break;
- case CHARSET_ACTION_SPLIT:
- n_children = 2;
- break;
- default:
- break;
- }
-
- for (i = 0; i < n_children; ++i) {
- h_llvm_free_charset_exec_plan(mm__, cep->children[i]);
- }
- h_free(cep->cs);
- h_free(cep);
- }
-}
-
-/*
- * Pretty-print a charset exec plan to stdout
- */
-
-static void h_llvm_pretty_print_charset_exec_plan_impl(HAllocator *mm__, llvm_charset_exec_plan_t *cep,
- const char *pfx_on_action_line, const char *pfx,
- int depth) {
- const char *action_string = NULL, *pfx_incr = NULL;
- const char *pfx_incr_child_action = NULL, *pfx_incr_last_child = NULL;
- char *next_pfx = NULL, *next_pfx_child_action_line = NULL, *next_pfx_last_child = NULL;
- int n_children = 0, i, j, next_pfx_len;
- uint8_t ch;
-
- if (!cep) {
- action_string = "NULL";
- } else {
- switch (cep->action) {
- case CHARSET_ACTION_ACCEPT:
- action_string = "CHARSET_ACTION_ACCEPT";
- break;
- case CHARSET_ACTION_SCAN:
- action_string = "CHARSET_ACTION_SCAN";
- break;
- case CHARSET_ACTION_BITMAP:
- action_string = "CHARSET_ACTION_BITMAP";
- break;
- case CHARSET_ACTION_COMPLEMENT:
- action_string = "CHARSET_ACTION_COMPLEMENT";
- n_children = 1;
- break;
- case CHARSET_ACTION_SPLIT:
- action_string = "CHARSET_ACTION_SPLIT";
- n_children = 2;
- break;
- default:
- action_string = "UNKNOWN";
- break;
- }
- }
-
- if (n_children > 0) {
- pfx_incr = " | ";
- } else {
- pfx_incr = " ";
- }
-
-
- if (depth > 0 || strlen(pfx_on_action_line) > 0) {
- printf("%s-%s\n", pfx_on_action_line, action_string);
- pfx_incr = (n_children > 0) ? " | " : " ";
- pfx_incr_child_action = " +-";
- pfx_incr_last_child = " ";
- } else {
- printf("%s\n", action_string);
- pfx_incr = (n_children > 0) ? "| " : " ";
- pfx_incr_child_action = "+-";
- pfx_incr_last_child = " ";
- }
-
- /*
- * Now do the charset, 8 lines of 32 bits with spaces in between to
- * fit [] range markers and | split point marker.
- */
- int open = 0, close = 0, split = 0;
- for (ch = 0, i = 0; i < 8; ++i) {
- /* Special case: [ should go before first char on line */
- if (ch == cep->idx_start) {
- printf("%s%s [", pfx, pfx_incr);
- } else {
- printf("%s%s ", pfx, pfx_incr);
- }
- for (j = 0; j < 32; ++j, ++ch) {
- open = close = split = 0;
- /* Figure out markers, avoid wraparound */
- if (cep->idx_start != 0 && ch + 1 == cep->idx_start) {
- /* There should be a [ right after this char */
- open = 1;
- } else if (ch == cep->idx_end) {
- /* There should be a ] right after this char */
- close = 1;
- } else if (ch == cep->split_point &&
- cep->action == CHARSET_ACTION_SPLIT) {
- /* There should be a | right after this char */
- split = 1;
- }
-
- if (charset_isset(cep->cs, ch)) printf("X");
- else printf(".");
-
- if (open) printf("[");
- else if (close) printf("]");
- else if (split) printf("|");
- else printf(" ");
- }
- printf("\n");
- }
-
- if (cep->action == CHARSET_ACTION_SPLIT) {
- printf("%s%s idx_start = %u, split_point = %u, idx_end = %u\n",
- pfx, pfx_incr, cep->idx_start, cep->split_point, cep->idx_end);
- } else {
- printf("%s%s idx_start = %u, idx_end = %u\n",
- pfx, pfx_incr, cep->idx_start, cep->idx_end);
- }
-
- printf("%s%s cost = %d, depth = %d\n", pfx, pfx_incr, cep->cost, cep->depth);
-
- if (n_children > 0) {
- if (n_children > 1) {
- next_pfx_len = strlen(pfx) + strlen(pfx_incr) + 1;
- next_pfx = h_new(char, next_pfx_len);
- snprintf(next_pfx, next_pfx_len, "%s%s", pfx, pfx_incr);
- } else {
- /* Won't be needed */
- next_pfx = NULL;
- }
- next_pfx_len = strlen(pfx) + strlen(pfx_incr_child_action) + 1;
- next_pfx_child_action_line = h_new(char, next_pfx_len);
- snprintf(next_pfx_child_action_line, next_pfx_len,
- "%s%s", pfx, pfx_incr_child_action);
- next_pfx_len = strlen(pfx) + strlen(pfx_incr_last_child) + 1;
- next_pfx_last_child = h_new(char, next_pfx_len);
- snprintf(next_pfx_last_child, next_pfx_len,
- "%s%s", pfx, pfx_incr_last_child);
-
- for (i = 0; i < n_children; ++i) {
- /* Space things out */
- printf("%s%s\n", pfx, pfx_incr);
- h_llvm_pretty_print_charset_exec_plan_impl(mm__, cep->children[i],
- next_pfx_child_action_line, (i + 1 == n_children) ? next_pfx_last_child : next_pfx,
- depth + 1);
- }
-
- if (next_pfx) h_free(next_pfx);
- h_free(next_pfx_last_child);
- h_free(next_pfx_child_action_line);
- }
-}
-
-static void h_llvm_pretty_print_charset_exec_plan(HAllocator *mm__, llvm_charset_exec_plan_t *cep) {
- /* Start at depth 0, and always emit an initial newline */
- printf("\n");
- h_llvm_pretty_print_charset_exec_plan_impl(mm__, cep, "", "", 0);
-}
-
-/*
- * Construct LLVM IR to decide if a runtime value is a member of a compile-time
- * character set, and branch depending on the result.
- *
- * Parameters:
- * - mod [in]: an LLVMModuleRef
- * - func [in]: an LLVMValueRef to the function to add the new basic blocks
- * - builder [in]: an LLVMBuilderRef, positioned appropriately
- * - r [in]: an LLVMValueRef to the value to test
- * - cs [in]: the HCharset to test membership in
- * - yes [in]: the basic block to branch to if r is in cs
- * - no [in]: the basic block to branch to if r is not in cs
- */
-
-void h_llvm_make_charset_membership_test(HAllocator* mm__,
- LLVMModuleRef mod, LLVMValueRef func, LLVMBuilderRef builder,
- LLVMValueRef r, HCharset cs,
- LLVMBasicBlockRef yes, LLVMBasicBlockRef no) {
- /*
- * A charset is a 256-element bit array, 32 bytes long in total. Ours is
- * static at compile time, so we can try to construct minimal LLVM IR for
- * this particular charset. In particular, we should handle cases like
- * only one or two bits being set, or a long consecutive range, efficiently.
- *
- * In LLVM IR, we can test propositions like r == x, r <= x, r >= x and their
- * negations efficiently, so the challenge here is to turn a character map
- * into a minimal set of such propositions.
- *
- * TODO: actually do this; right now for the sake of a first pass we're just
- * testing r == x for every x in cs.
- */
-
- /* Try building a charset exec plan */
- llvm_charset_exec_plan_t *cep = h_llvm_build_charset_exec_plan(mm__, cs);
- if (cep) {
- /* For now just check it and free it */
- bool ok = h_llvm_check_charset_exec_plan(cep);
- if (ok) fprintf(stderr, "cep %p passes consistency check\n", (void *)cep);
- else fprintf(stderr, "cep %p fails consistency check\n", (void *)cep);
- h_llvm_pretty_print_charset_exec_plan(mm__, cep);
- h_llvm_free_charset_exec_plan(mm__, cep);
- cep = NULL;
- } else {
- fprintf(stderr, "got null from h_llvm_build_charset_exec_plan()\n");
- }
-
- for (int i = 0; i < 256; ++i) {
- if (charset_isset(cs, i)) {
- char bbname[16];
- uint8_t c = (uint8_t)i;
- snprintf(bbname, 16, "cs_memb_%02x", c);
- LLVMValueRef icmp = LLVMBuildICmp(builder, LLVMIntEQ,
- LLVMConstInt(LLVMInt8Type(), c, 0), r, "c == r");
- LLVMBasicBlockRef bb = LLVMAppendBasicBlock(func, bbname);
- LLVMBuildCondBr(builder, icmp, yes, bb);
- LLVMPositionBuilderAtEnd(builder, bb);
- }
- }
-
- LLVMBuildBr(builder, no);
-}
-
/*
* Construct LLVM IR to allocate a token of type TT_SINT or TT_UINT
*
diff --git a/src/backends/llvm/llvm_charset.c b/src/backends/llvm/llvm_charset.c
new file mode 100644
index 00000000..1e8591dc
--- /dev/null
+++ b/src/backends/llvm/llvm_charset.c
@@ -0,0 +1,855 @@
+#ifdef HAMMER_LLVM_BACKEND
+
+#include <llvm-c/Analysis.h>
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wpedantic"
+#include <llvm-c/Core.h>
+#pragma GCC diagnostic pop
+#include <llvm-c/ExecutionEngine.h>
+#include "../../internal.h"
+#include "llvm.h"
+
+typedef enum {
+ /*
+ * Accept action; this entire range is in the charset. This action type
+ * has no children and terminates handling the input character.
+ */
+ CHARSET_ACTION_ACCEPT,
+ /*
+ * Scan action; test input char against each set character in the charset.
+ * This action type has no children and terminates handling the input
+ * character.
+ */
+ CHARSET_ACTION_SCAN,
+ /*
+ * Bitmap action; test input char against a bitmap in the IR at fixed
+ * cost.
+ */
+ CHARSET_ACTION_BITMAP,
+ /*
+ * Complement action; invert the sense of the charset. This action type
+ * has one child node, with the bounds unchanged and the portion of the
+ * charset within the bounds complemented.
+ */
+ CHARSET_ACTION_COMPLEMENT,
+ /*
+ * Split action; check whether the input char is above or below a split
+ * point, and branch into one of two children depending.
+ */
+ CHARSET_ACTION_SPLIT
+} llvm_charset_exec_plan_action_t;
+
+typedef struct llvm_charset_exec_plan_s llvm_charset_exec_plan_t;
+struct llvm_charset_exec_plan_s {
+ /*
+ * The charset at this node, with transforms such as range restriction
+ * or complementation applied.
+ */
+ HCharset cs;
+ /*
+ * Char values for the range of this node, and the split point if this
+ * is CHARSET_ACTION_SPLIT
+ */
+ uint8_t idx_start, idx_end, split_point;
+ /* Action to take at this node */
+ llvm_charset_exec_plan_action_t action;
+ /* Estimated cost metric */
+ int cost;
+ /* Depth in exec plan */
+ int depth;
+ /* Children, if any (zero, one or two depending on action) */
+ llvm_charset_exec_plan_t *children[2];
+};
+
+/* Forward prototypes for charset llvm stuff */
+static int h_llvm_build_charset_exec_plan_impl(HAllocator* mm__, HCharset cs,
+ llvm_charset_exec_plan_t *parent, llvm_charset_exec_plan_t *cep,
+ int allow_complement, uint8_t *split_point);
+static llvm_charset_exec_plan_t * h_llvm_build_charset_exec_plan_impl_alloc(
+ HAllocator* mm__, llvm_charset_exec_plan_t *parent, HCharset cs,
+ uint8_t idx_start, uint8_t idx_end, int allow_complement);
+static void h_llvm_free_charset_exec_plan(HAllocator* mm__,
+ llvm_charset_exec_plan_t *cep);
+
+/*
+ * Check if this charset is eligible for CHARSET_ACTION_ACCEPT on a range
+ */
+
+static int h_llvm_charset_eligible_for_accept(HCharset cs, uint8_t idx_start, uint8_t idx_end) {
+ int eligible = 1, i;
+
+ for (i = idx_start; i <= idx_end; ++i) {
+ if (!(charset_isset(cs, (uint8_t)i))) {
+ eligible = 0;
+ break;
+ }
+ }
+
+ return eligible;
+}
+
+/*
+ * Estimate cost of CHARSET_ACTION_SCAN for this charset (~proportional to number of set chars, min 1)
+ */
+
+static int h_llvm_charset_estimate_scan_cost(HCharset cs, uint8_t idx_start, uint8_t idx_end) {
+ int i, cost;
+
+ cost = 1;
+ for (i = idx_start; i <= idx_end; ++i) {
+ if (charset_isset(cs, (uint8_t)i)) ++cost;
+ }
+
+ return cost;
+}
+
+/*
+ * Given a skeletal CHARSET_ACTION_SPLIT node from h_llvm_build_charset_exec_plan_impl(),
+ * binary search for the best split point we can find and return the cost metric.
+ * Unfortunately the search space is quite large, so we're going to use some silly
+ * heuristics here such as looking for the longest run of present or absent chars at
+ * one end of a charset, and proposing it as a split, or just trying the midpoint.
+ * It may be possible to do better.
+ */
+
+static int h_llvm_find_best_split(HAllocator* mm__, llvm_charset_exec_plan_t *split) {
+ int rv, best_end_run, i, contiguous;
+ uint8_t best_end_run_split, midpoint;
+ llvm_charset_exec_plan_t *best_left, *best_right, *left, *right;
+ int best_cost, cost;
+
+ /* Sanity-check: we should be a split with a range at least two indices long */
+ if (!split || split->action != CHARSET_ACTION_SPLIT) return -1;
+ if (split->idx_end <= split->idx_start) return -1;
+
+ /* Find the longest end run; split a run of length 1 at the left end as a
+ * fallback, since there's always a run of length 1 at each end. */
+ best_end_run = 1;
+ best_end_run_split = split->idx_start;
+ contiguous = 0;
+ /* Try the low end */
+ i = 0;
+ while (i <= split->idx_end - split->idx_start &&
+ (charset_isset(split->cs, split->idx_start + i) ==
+ charset_isset(split->cs, split->idx_start))) ++i;
+ if (i <= split->idx_end - split->idx_start) {
+ /* This run has length i */
+ if (i > best_end_run) {
+ best_end_run = i;
+ /*
+ * -1 since split points are last index of left child, and i
+ * is first index that wasn't in the run
+ */
+ best_end_run_split = split->idx_start + i - 1;
+ }
+
+ /* Now the same thing from the high end */
+ i = 0;
+ while (i <= split->idx_end - split->idx_start &&
+ (charset_isset(split->cs, split->idx_end - i) ==
+ charset_isset(split->cs, split->idx_end))) ++i;
+ if (i <= split->idx_end - split->idx_start && i > best_end_run) {
+ best_end_run = i;
+ best_end_run_split = split->idx_end - i;
+ }
+ } else {
+ /* Wow, contiguous - any split will turn out well - just use the midpoint */
+ contiguous = 1;
+ }
+
+ /* Initialize, start trying things */
+ best_left = best_right = left = right = NULL;
+ rv = -1;
+
+ /* Try a midpoint split */
+ midpoint = split->idx_start + (split->idx_end - split->idx_start) / 2;
+ left = h_llvm_build_charset_exec_plan_impl_alloc(mm__, split, split->cs,
+ split->idx_start, midpoint, 1);
+ right = h_llvm_build_charset_exec_plan_impl_alloc(mm__, split, split->cs,
+ midpoint + 1, split->idx_end, 1);
+ if (left && right) {
+ /* Cost of the split == 1 + max(left->cost, right->cost) */
+ cost = left->cost;
+ if (right->cost > cost) cost = right->cost;
+ ++cost;
+ /* We haven't tried the end-run one yet, so always accept this */
+ best_left = left;
+ best_right = right;
+ best_cost = cost;
+ left = right = NULL;
+ } else goto err;
+
+ /*
+ * Try an end-run split; if we decided we had a contiguous run earlier,
+ * all are equally good, so don't bother and just use the midpoint
+ */
+
+ if (!contiguous) {
+ /*
+ * Sanity-check the indices; error out if the scanner gave us
+ * something silly
+ */
+ if (best_end_run_split < split->idx_start ||
+ best_end_run_split >= split->idx_end) goto err;
+ left = h_llvm_build_charset_exec_plan_impl_alloc(mm__, split, split->cs,
+ split->idx_start, best_end_run_split, 1);
+ right = h_llvm_build_charset_exec_plan_impl_alloc(mm__, split, split->cs,
+ best_end_run_split + 1, split->idx_end, 1);
+ if (left && right) {
+ /* Cost of the split == 1 + max(left->cost, right->cost) */
+ cost = left->cost;
+ if (right->cost > cost) cost = right->cost;
+ ++cost;
+ /* Check if against what we already have */
+ if (cost < best_cost) {
+ if (best_left) h_llvm_free_charset_exec_plan(mm__, best_left);
+ if (best_right) h_llvm_free_charset_exec_plan(mm__, best_right);
+ best_left = left;
+ best_right = right;
+ best_cost = cost;
+ left = right = NULL;
+ }
+ } else goto err;
+ }
+
+ /* Set up the split node with our best results */
+ split->cost = best_cost;
+ split->children[0] = best_left;
+ split->children[1] = best_right;
+ split->split_point = best_left->idx_end;
+ best_left = best_right = NULL;
+ rv = split->cost;
+
+ err:
+ /* Error/cleanup case */
+ if (left) h_llvm_free_charset_exec_plan(mm__, left);
+ if (right) h_llvm_free_charset_exec_plan(mm__, right);
+ if (best_left) h_llvm_free_charset_exec_plan(mm__, best_left);
+ if (best_right) h_llvm_free_charset_exec_plan(mm__, best_right);
+
+ return rv;
+}
+
+/*
+ * Setup call to h_llvm_build_charset_exec_plan_impl(), while allocating a new
+ * llvm_charset_exec_plan_t.
+ */
+static llvm_charset_exec_plan_t * h_llvm_build_charset_exec_plan_impl_alloc(
+ HAllocator* mm__, llvm_charset_exec_plan_t *parent, HCharset cs,
+ uint8_t idx_start, uint8_t idx_end, int allow_complement) {
+ int cost;
+ llvm_charset_exec_plan_t *cep;
+
+ if (!mm__) return NULL;
+ if (!cs) return NULL;
+ if (idx_start > idx_end) return NULL;
+
+ cep = h_new(llvm_charset_exec_plan_t, 1);
+ memset(cep, 0, sizeof(*cep));
+ cep->cs = NULL;
+ /*
+ * Initializing these is important; if the parent is CHARSET_ACTION_SPLIT,
+ * these are how h_llvm_build_charset_exec_plan_impl() knows the range for
+ * the child it's constructing.
+ */
+ cep->idx_start = idx_start;
+ cep->idx_end = idx_end;
+ cost = h_llvm_build_charset_exec_plan_impl(mm__, cs, parent, cep,
+ allow_complement, NULL);
+ if (cost >= 0) cep->cost = cost;
+ else {
+ h_llvm_free_charset_exec_plan(mm__, cep);
+ cep = NULL;
+ }
+
+ return cep;
+}
+
+/*
+ * Given a charset, optionally its parent containing range restrictions, and
+ * an allow_complement parameter, search for the best exec plan and write it
+ * to another (skeletal) charset which will receive an action and range. If
+ * the action is CHARSET_ACTION_SPLIT, also output a split point. Return a
+ * cost estimate.
+ */
+
+static int h_llvm_build_charset_exec_plan_impl(HAllocator* mm__, HCharset cs,
+ llvm_charset_exec_plan_t *parent, llvm_charset_exec_plan_t *cep,
+ int allow_complement, uint8_t *split_point) {
+ int eligible_for_accept, best_cost, depth;
+ int estimated_complement_cost, estimated_scan_cost, estimated_split_cost;
+ int estimated_bitmap_cost;
+ uint8_t idx_start, idx_end;
+ llvm_charset_exec_plan_t complement_cep, split_cep;
+ llvm_charset_exec_plan_action_t chosen_action;
+
+ /* Check args */
+ if (!(mm__ && cep)) return -1;
+
+ /*
+ * The index bounds come from either the parent or maximal bounds by
+ * default. Exception is the case that we are a child of a split, in
+ * which case h_llvm_find_best_split() should have set bounds in cep.
+ */
+ if (parent && parent->action == CHARSET_ACTION_SPLIT &&
+ ((cep->idx_start == parent->idx_start &&
+ cep->idx_end < parent->idx_end) ||
+ (cep->idx_start > parent->idx_start &&
+ cep->idx_end == parent->idx_end))) {
+ idx_start = cep->idx_start;
+ idx_end = cep->idx_end;
+ } else if (parent) {
+ idx_start = parent->idx_start;
+ idx_end = parent->idx_end;
+ } else {
+ idx_start = 0;
+ idx_end = UINT8_MAX;
+ }
+
+ /* Get the depth in the exec plan */
+ if (parent) depth = parent->depth + 1;
+ else depth = 0;
+
+ eligible_for_accept = h_llvm_charset_eligible_for_accept(cs, idx_start, idx_end);
+ if (eligible_for_accept) {
+ /* if we can use CHARSET_ACTION_ACCEPT, always do so */
+ cep->cs = copy_charset(mm__, cs);
+ charset_restrict_to_range(cep->cs, idx_start, idx_end);
+ cep->idx_start = idx_start;
+ cep->idx_end = idx_end;
+ cep->split_point = 0;
+ /* Acceptance (or rejection, under a complement) is free */
+ cep->cost = 0;
+ cep->depth = depth;
+ cep->action = CHARSET_ACTION_ACCEPT;
+ cep->children[0] = NULL;
+ cep->children[1] = NULL;
+
+ return cep->cost;
+ } else {
+ /*
+ * Estimate cost for CHARSET_ACTION_SCAN, and for the tree below
+ * CHARSET_ACTION_COMPLEMENT if we are eligible to use it.
+ */
+ estimated_scan_cost = h_llvm_charset_estimate_scan_cost(cs, idx_start, idx_end);
+ /*
+ * We can always use CHARSET_ACTION_BITMAP; this constant controls how
+ * strongly we prefer it over the compare-and-branch approach.
+ */
+ estimated_bitmap_cost = 6;
+ /* >= 0 is a flag we have a complement we may need to free later */
+ estimated_complement_cost = -1;
+ if (allow_complement) {
+ HCharset child_cs;
+
+ /* Complement the charset within the range */
+ memset(&complement_cep, 0, sizeof(complement_cep));
+ complement_cep.cs = copy_charset(mm__, cs);
+ charset_restrict_to_range(complement_cep.cs, idx_start, idx_end);
+ child_cs = copy_charset(mm__, complement_cep.cs);
+ charset_complement(child_cs);
+ charset_restrict_to_range(child_cs, idx_start, idx_end);
+ complement_cep.idx_start = idx_start;
+ complement_cep.idx_end = idx_end;
+ complement_cep.split_point = 0;
+ complement_cep.depth = depth;
+ complement_cep.action = CHARSET_ACTION_COMPLEMENT;
+ complement_cep.children[0] = h_new(llvm_charset_exec_plan_t, 1);
+ memset(complement_cep.children[0], 0, sizeof(llvm_charset_exec_plan_t));
+ complement_cep.children[1] = NULL;
+ /*
+ * Find the child; the complement has cost 0 since it just swizzles success
+ * and fail output basic blocks; it's important we test for complement last
+ * below then, so we break ties in favor of not stacking complements up. We
+ * set allow_complement = 0 so we never stack two complements.
+ */
+ complement_cep.cost = h_llvm_build_charset_exec_plan_impl(mm__, child_cs, &complement_cep,
+ complement_cep.children[0], 0, NULL);
+ estimated_complement_cost = complement_cep.cost;
+ h_free(child_cs);
+ }
+
+ /*
+ * Set up split node if it makes sense; the depth cutoff here limits the
+ * cost of the search for complex charsets.
+ */
+ if (idx_start < idx_end && depth < 5) {
+ split_cep.cs = copy_charset(mm__, cs);
+ charset_restrict_to_range(split_cep.cs, idx_start, idx_end);
+ split_cep.idx_start = idx_start;
+ split_cep.idx_end = idx_end;
+ split_cep.split_point = 0;
+ split_cep.action = CHARSET_ACTION_SPLIT;
+ split_cep.cost = -1;
+ split_cep.depth = depth;
+ split_cep.children[0] = NULL;
+ split_cep.children[1] = NULL;
+ /* h_llvm_find_best_split() sets split_cep.cost */
+ estimated_split_cost = h_llvm_find_best_split(mm__, &split_cep);
+ if (estimated_split_cost < 0) {
+ /* This shouldn't happen, but make sure we free the charset */
+ h_free(split_cep.cs);
+ }
+ } else {
+ estimated_split_cost = -1;
+ }
+
+ /* Pick the action type with the lowest cost */
+ best_cost = -1;
+ if (estimated_scan_cost >= 0 &&
+ (best_cost < 0 || estimated_scan_cost < best_cost)) {
+ chosen_action = CHARSET_ACTION_SCAN;
+ best_cost = estimated_scan_cost;
+ }
+
+ if (estimated_bitmap_cost >= 0 &&
+ (best_cost < 0 || estimated_bitmap_cost < best_cost)) {
+ chosen_action = CHARSET_ACTION_BITMAP;
+ best_cost = estimated_bitmap_cost;
+ }
+
+ if (estimated_split_cost >= 0 &&
+ (best_cost < 0 || estimated_split_cost < best_cost)) {
+ chosen_action = CHARSET_ACTION_SPLIT;
+ best_cost = estimated_split_cost;
+ }
+
+ if (allow_complement && estimated_complement_cost >= 0 &&
+ (best_cost < 0 || estimated_complement_cost < best_cost)) {
+ chosen_action = CHARSET_ACTION_COMPLEMENT;
+ best_cost = estimated_complement_cost;
+ }
+
+ /* Fill out cep based on the chosen action */
+ switch (chosen_action) {
+ case CHARSET_ACTION_SCAN:
+ /* Set up a scan */
+ cep->cs = copy_charset(mm__, cs);
+ charset_restrict_to_range(cep->cs, idx_start, idx_end);
+ cep->idx_start = idx_start;
+ cep->idx_end = idx_end;
+ cep->split_point = 0;
+ cep->action = CHARSET_ACTION_SCAN;
+ cep->cost = estimated_scan_cost;
+ cep->depth = depth;
+ cep->children[0] = NULL;
+ cep->children[1] = NULL;
+ break;
+ case CHARSET_ACTION_BITMAP:
+ /* Set up a bitmap */
+ cep->cs = copy_charset(mm__, cs);
+ charset_restrict_to_range(cep->cs, idx_start, idx_end);
+ cep->idx_start = idx_start;
+ cep->idx_end = idx_end;
+ cep->split_point = 0;
+ cep->action = CHARSET_ACTION_BITMAP;
+ cep->cost = estimated_bitmap_cost;
+ cep->depth = depth;
+ cep->children[0] = NULL;
+ cep->children[1] = NULL;
+ break;
+ case CHARSET_ACTION_COMPLEMENT:
+ /*
+ * We have a CEP filled out we can just copy over; be sure to set
+ * estimated_complement_cost = -1 so we know not to free it on the
+ * way out.
+ */
+ memcpy(cep, &complement_cep, sizeof(complement_cep));
+ memset(&complement_cep, 0, sizeof(complement_cep));
+ estimated_complement_cost = -1;
+ break;
+ case CHARSET_ACTION_SPLIT:
+ /*
+ * We have a CEP filled out we can just copy over; be sure to set
+ * estimated_split_cost = -1 so we know not to free it on the way
+ * out.
+ */
+ memcpy(cep, &split_cep, sizeof(split_cep));
+ memset(&split_cep, 0, sizeof(split_cep));
+ estimated_split_cost = -1;
+ break;
+ default:
+ /* Not supported */
+ best_cost = -1;
+ memset(cep, 0, sizeof(*cep));
+ break;
+ }
+ }
+
+ /* Free temporary CEPs if needed */
+
+ if (estimated_complement_cost >= 0) {
+ /*
+ * We have a complement_cep we ended up not using; free its child and
+ * charset
+ */
+ h_llvm_free_charset_exec_plan(mm__, complement_cep.children[0]);
+ h_free(complement_cep.cs);
+ memset(&complement_cep, 0, sizeof(complement_cep));
+ estimated_complement_cost = -1;
+ }
+
+ if (estimated_split_cost >= 0) {
+ /*
+ * We have a split_cep we ended up not using; free its children and
+ * charset.
+ */
+ h_llvm_free_charset_exec_plan(mm__, split_cep.children[0]);
+ h_llvm_free_charset_exec_plan(mm__, split_cep.children[1]);
+ h_free(split_cep.cs);
+ memset(&split_cep, 0, sizeof(split_cep));
+ estimated_split_cost = -1;
+ }
+
+ return best_cost;
+}
+
+/*
+ * Build a charset exec plan for a charset
+ */
+
+static llvm_charset_exec_plan_t * h_llvm_build_charset_exec_plan(
+ HAllocator* mm__, HCharset cs) {
+ llvm_charset_exec_plan_t *cep = NULL;
+ int best_cost;
+
+ cep = h_new(llvm_charset_exec_plan_t, 1);
+ best_cost = h_llvm_build_charset_exec_plan_impl(mm__, cs, NULL, cep, 1, NULL);
+
+ if (best_cost < 0) {
+ /* h_llvm_build_charset_exec_plan_impl() failed */
+ h_free(cep);
+ cep = NULL;
+ }
+
+ return cep;
+}
+
+/*
+ * Consistency-check a charset exec plan
+ */
+
+static bool h_llvm_check_charset_exec_plan(llvm_charset_exec_plan_t *cep) {
+ bool consistent = false;
+ uint8_t i;
+
+ if (cep) {
+ /* Check that we have a charset */
+ if (!(cep->cs)) goto done;
+ /* Check that the range makes sense */
+ if (cep->idx_start > cep->idx_end) goto done;
+ /* Check that the charset is empty outside the range */
+ for (i = 0; i < cep->idx_start; ++i) {
+ /* Failed check */
+ if (charset_isset(cep->cs, i)) goto done;
+ /* Prevent wraparound */
+ if (i == UINT8_MAX) break;
+ }
+
+ if (cep->idx_end < UINT8_MAX) {
+ /* We break at the end */
+ for (i = cep->idx_end + 1; ; ++i) {
+ /* Failed check */
+ if (charset_isset(cep->cs, i)) goto done;
+ /* Prevent wraparound */
+ if (i == UINT8_MAX) break;
+ }
+ }
+
+ /* Minimum cost estimate is 0; complements and accepts can be free */
+ if (cep->cost < 0) goto done;
+
+ /* No split point unlesswe're CHARSET_ACTION_SPLIT */
+ if (cep->action != CHARSET_ACTION_SPLIT && cep->split_point != 0) goto done;
+
+ /* Action type dependent part */
+ switch (cep->action) {
+ case CHARSET_ACTION_ACCEPT:
+ case CHARSET_ACTION_SCAN:
+ case CHARSET_ACTION_BITMAP:
+ /* These are always okay and have no children */
+ if (cep->children[0] || cep->children[1]) goto done;
+ consistent = true;
+ break;
+ case CHARSET_ACTION_COMPLEMENT:
+ /* This has one child, which should have the same range */
+ if (cep->children[1]) goto done;
+ if (cep->children[0]) {
+ if (cep->children[0]->idx_start == cep->idx_start &&
+ cep->children[0]->idx_end == cep->idx_end) {
+ /* The cost cannot be lower than the child */
+ if (cep->cost < cep->children[0]->cost) goto done;
+ /* Okay, we're consistent if the child node is */
+ consistent = h_llvm_check_charset_exec_plan(cep->children[0]);
+ }
+ }
+ break;
+ case CHARSET_ACTION_SPLIT:
+ /* This has two children, which should split the range */
+ if (cep->children[0] && cep->children[1]) {
+ if (cep->children[0]->idx_start == cep->idx_start &&
+ cep->children[0]->idx_end + 1 == cep->children[1]->idx_start &&
+ cep->children[1]->idx_end == cep->idx_end) {
+ /* The split point must match the children */
+ if (cep->split_point != cep->children[0]->idx_end) goto done;
+ /*
+ * The cost must be in the range defined by the children, + 1 for
+ * the comparison at most
+ */
+ int child_min_cost = (cep->children[0]->cost < cep->children[1]->cost) ?
+ cep->children[0]->cost : cep->children[1]->cost;
+ int child_max_cost = (cep->children[0]->cost > cep->children[1]->cost) ?
+ cep->children[0]->cost : cep->children[1]->cost;
+ if ((cep->cost < child_min_cost) || (cep->cost > child_max_cost + 1)) goto done;
+ /* Okay, we're consistent if both children are */
+ consistent = h_llvm_check_charset_exec_plan(cep->children[0]) &&
+ h_llvm_check_charset_exec_plan(cep->children[1]);
+ }
+ }
+ break;
+ default:
+ break;
+ }
+ }
+
+ done:
+ return consistent;
+}
+
+/*
+ * Free a charset exec plan using the supplied allocator
+ */
+
+static void h_llvm_free_charset_exec_plan(HAllocator* mm__,
+ llvm_charset_exec_plan_t *cep) {
+ int n_children, i;
+
+ if (cep) {
+ n_children = 0;
+ switch (cep->action) {
+ case CHARSET_ACTION_COMPLEMENT:
+ n_children = 1;
+ break;
+ case CHARSET_ACTION_SPLIT:
+ n_children = 2;
+ break;
+ default:
+ break;
+ }
+
+ for (i = 0; i < n_children; ++i) {
+ h_llvm_free_charset_exec_plan(mm__, cep->children[i]);
+ }
+ h_free(cep->cs);
+ h_free(cep);
+ }
+}
+
+/*
+ * Pretty-print a charset exec plan to stdout
+ */
+
+static void h_llvm_pretty_print_charset_exec_plan_impl(HAllocator *mm__, llvm_charset_exec_plan_t *cep,
+ const char *pfx_on_action_line, const char *pfx,
+ int depth) {
+ const char *action_string = NULL, *pfx_incr = NULL;
+ const char *pfx_incr_child_action = NULL, *pfx_incr_last_child = NULL;
+ char *next_pfx = NULL, *next_pfx_child_action_line = NULL, *next_pfx_last_child = NULL;
+ int n_children = 0, i, j, next_pfx_len;
+ uint8_t ch;
+
+ if (!cep) {
+ action_string = "NULL";
+ } else {
+ switch (cep->action) {
+ case CHARSET_ACTION_ACCEPT:
+ action_string = "CHARSET_ACTION_ACCEPT";
+ break;
+ case CHARSET_ACTION_SCAN:
+ action_string = "CHARSET_ACTION_SCAN";
+ break;
+ case CHARSET_ACTION_BITMAP:
+ action_string = "CHARSET_ACTION_BITMAP";
+ break;
+ case CHARSET_ACTION_COMPLEMENT:
+ action_string = "CHARSET_ACTION_COMPLEMENT";
+ n_children = 1;
+ break;
+ case CHARSET_ACTION_SPLIT:
+ action_string = "CHARSET_ACTION_SPLIT";
+ n_children = 2;
+ break;
+ default:
+ action_string = "UNKNOWN";
+ break;
+ }
+ }
+
+ if (n_children > 0) {
+ pfx_incr = " | ";
+ } else {
+ pfx_incr = " ";
+ }
+
+
+ if (depth > 0 || strlen(pfx_on_action_line) > 0) {
+ printf("%s-%s\n", pfx_on_action_line, action_string);
+ pfx_incr = (n_children > 0) ? " | " : " ";
+ pfx_incr_child_action = " +-";
+ pfx_incr_last_child = " ";
+ } else {
+ printf("%s\n", action_string);
+ pfx_incr = (n_children > 0) ? "| " : " ";
+ pfx_incr_child_action = "+-";
+ pfx_incr_last_child = " ";
+ }
+
+ /*
+ * Now do the charset, 8 lines of 32 bits with spaces in between to
+ * fit [] range markers and | split point marker.
+ */
+ int open = 0, close = 0, split = 0;
+ for (ch = 0, i = 0; i < 8; ++i) {
+ /* Special case: [ should go before first char on line */
+ if (ch == cep->idx_start) {
+ printf("%s%s [", pfx, pfx_incr);
+ } else {
+ printf("%s%s ", pfx, pfx_incr);
+ }
+ for (j = 0; j < 32; ++j, ++ch) {
+ open = close = split = 0;
+ /* Figure out markers, avoid wraparound */
+ if (cep->idx_start != 0 && ch + 1 == cep->idx_start) {
+ /* There should be a [ right after this char */
+ open = 1;
+ } else if (ch == cep->idx_end) {
+ /* There should be a ] right after this char */
+ close = 1;
+ } else if (ch == cep->split_point &&
+ cep->action == CHARSET_ACTION_SPLIT) {
+ /* There should be a | right after this char */
+ split = 1;
+ }
+
+ if (charset_isset(cep->cs, ch)) printf("X");
+ else printf(".");
+
+ if (open) printf("[");
+ else if (close) printf("]");
+ else if (split) printf("|");
+ else printf(" ");
+ }
+ printf("\n");
+ }
+
+ if (cep->action == CHARSET_ACTION_SPLIT) {
+ printf("%s%s idx_start = %u, split_point = %u, idx_end = %u\n",
+ pfx, pfx_incr, cep->idx_start, cep->split_point, cep->idx_end);
+ } else {
+ printf("%s%s idx_start = %u, idx_end = %u\n",
+ pfx, pfx_incr, cep->idx_start, cep->idx_end);
+ }
+
+ printf("%s%s cost = %d, depth = %d\n", pfx, pfx_incr, cep->cost, cep->depth);
+
+ if (n_children > 0) {
+ if (n_children > 1) {
+ next_pfx_len = strlen(pfx) + strlen(pfx_incr) + 1;
+ next_pfx = h_new(char, next_pfx_len);
+ snprintf(next_pfx, next_pfx_len, "%s%s", pfx, pfx_incr);
+ } else {
+ /* Won't be needed */
+ next_pfx = NULL;
+ }
+ next_pfx_len = strlen(pfx) + strlen(pfx_incr_child_action) + 1;
+ next_pfx_child_action_line = h_new(char, next_pfx_len);
+ snprintf(next_pfx_child_action_line, next_pfx_len,
+ "%s%s", pfx, pfx_incr_child_action);
+ next_pfx_len = strlen(pfx) + strlen(pfx_incr_last_child) + 1;
+ next_pfx_last_child = h_new(char, next_pfx_len);
+ snprintf(next_pfx_last_child, next_pfx_len,
+ "%s%s", pfx, pfx_incr_last_child);
+
+ for (i = 0; i < n_children; ++i) {
+ /* Space things out */
+ printf("%s%s\n", pfx, pfx_incr);
+ h_llvm_pretty_print_charset_exec_plan_impl(mm__, cep->children[i],
+ next_pfx_child_action_line, (i + 1 == n_children) ? next_pfx_last_child : next_pfx,
+ depth + 1);
+ }
+
+ if (next_pfx) h_free(next_pfx);
+ h_free(next_pfx_last_child);
+ h_free(next_pfx_child_action_line);
+ }
+}
+
+static void h_llvm_pretty_print_charset_exec_plan(HAllocator *mm__, llvm_charset_exec_plan_t *cep) {
+ /* Start at depth 0, and always emit an initial newline */
+ printf("\n");
+ h_llvm_pretty_print_charset_exec_plan_impl(mm__, cep, "", "", 0);
+}
+
+/*
+ * Construct LLVM IR to decide if a runtime value is a member of a compile-time
+ * character set, and branch depending on the result.
+ *
+ * Parameters:
+ * - mod [in]: an LLVMModuleRef
+ * - func [in]: an LLVMValueRef to the function to add the new basic blocks
+ * - builder [in]: an LLVMBuilderRef, positioned appropriately
+ * - r [in]: an LLVMValueRef to the value to test
+ * - cs [in]: the HCharset to test membership in
+ * - yes [in]: the basic block to branch to if r is in cs
+ * - no [in]: the basic block to branch to if r is not in cs
+ */
+
+void h_llvm_make_charset_membership_test(HAllocator* mm__,
+ LLVMModuleRef mod, LLVMValueRef func, LLVMBuilderRef builder,
+ LLVMValueRef r, HCharset cs,
+ LLVMBasicBlockRef yes, LLVMBasicBlockRef no) {
+ /*
+ * A charset is a 256-element bit array, 32 bytes long in total. Ours is
+ * static at compile time, so we can try to construct minimal LLVM IR for
+ * this particular charset. In particular, we should handle cases like
+ * only one or two bits being set, or a long consecutive range, efficiently.
+ *
+ * In LLVM IR, we can test propositions like r == x, r <= x, r >= x and their
+ * negations efficiently, so the challenge here is to turn a character map
+ * into a minimal set of such propositions.
+ *
+ * TODO: actually do this; right now for the sake of a first pass we're just
+ * testing r == x for every x in cs.
+ */
+
+ /* Try building a charset exec plan */
+ llvm_charset_exec_plan_t *cep = h_llvm_build_charset_exec_plan(mm__, cs);
+ if (cep) {
+ /* For now just check it and free it */
+ bool ok = h_llvm_check_charset_exec_plan(cep);
+ if (ok) fprintf(stderr, "cep %p passes consistency check\n", (void *)cep);
+ else fprintf(stderr, "cep %p fails consistency check\n", (void *)cep);
+ h_llvm_pretty_print_charset_exec_plan(mm__, cep);
+ h_llvm_free_charset_exec_plan(mm__, cep);
+ cep = NULL;
+ } else {
+ fprintf(stderr, "got null from h_llvm_build_charset_exec_plan()\n");
+ }
+
+ for (int i = 0; i < 256; ++i) {
+ if (charset_isset(cs, i)) {
+ char bbname[16];
+ uint8_t c = (uint8_t)i;
+ snprintf(bbname, 16, "cs_memb_%02x", c);
+ LLVMValueRef icmp = LLVMBuildICmp(builder, LLVMIntEQ,
+ LLVMConstInt(LLVMInt8Type(), c, 0), r, "c == r");
+ LLVMBasicBlockRef bb = LLVMAppendBasicBlock(func, bbname);
+ LLVMBuildCondBr(builder, icmp, yes, bb);
+ LLVMPositionBuilderAtEnd(builder, bb);
+ }
+ }
+
+ LLVMBuildBr(builder, no);
+}
+
+#endif /* defined(HAMMER_LLVM_BACKEND) */
--
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