From 5d4587ce6580c47a07903af16804aba668fdfc24 Mon Sep 17 00:00:00 2001
From: Andrea Shepard <andrea@persephoneslair.org>
Date: Mon, 21 Nov 2016 05:07:35 +0000
Subject: [PATCH] Implement IR generation for CHARSET_ACTION_SCAN,
CHARSET_ACTION_ACCEPT and CHARSET_ACTION_COMPLEMENT
---
src/backends/llvm/llvm.h | 2 +-
src/backends/llvm/llvm_charset.c | 156 ++++++++++++++++++++++++++-----
src/parsers/charset.c | 5 +-
3 files changed, 136 insertions(+), 27 deletions(-)
diff --git a/src/backends/llvm/llvm.h b/src/backends/llvm/llvm.h
index 36f53fcb..a05693bc 100644
--- a/src/backends/llvm/llvm.h
+++ b/src/backends/llvm/llvm.h
@@ -13,7 +13,7 @@
LLVMTypeRef llvm_inputstream, llvm_inputstreamptr, llvm_arena, llvm_arenaptr;
LLVMTypeRef llvm_parsedtoken, llvm_parsedtokenptr, llvm_parseresult, llvm_parseresultptr;
-void h_llvm_make_charset_membership_test(HAllocator* mm__,
+bool h_llvm_make_charset_membership_test(HAllocator* mm__,
LLVMModuleRef mod, LLVMValueRef func, LLVMBuilderRef builder,
LLVMValueRef r, HCharset cs,
LLVMBasicBlockRef yes, LLVMBasicBlockRef no);
diff --git a/src/backends/llvm/llvm_charset.c b/src/backends/llvm/llvm_charset.c
index 1e8591dc..e2f52b18 100644
--- a/src/backends/llvm/llvm_charset.c
+++ b/src/backends/llvm/llvm_charset.c
@@ -9,6 +9,12 @@
#include "../../internal.h"
#include "llvm.h"
+/*
+ * Set this #define to enable some debug logging and internal consistency
+ * checking.
+ */
+#define HAMMER_LLVM_CHARSET_DEBUG
+
typedef enum {
/*
* Accept action; this entire range is in the charset. This action type
@@ -790,6 +796,97 @@ static void h_llvm_pretty_print_charset_exec_plan(HAllocator *mm__, llvm_charset
h_llvm_pretty_print_charset_exec_plan_impl(mm__, cep, "", "", 0);
}
+/*
+ * Build IR for a CHARSET_ACTION_SCAN
+ */
+
+static bool h_llvm_build_ir_for_scan(LLVMModuleRef mod, LLVMValueRef func, LLVMBuilderRef builder,
+ HCharset cs, uint8_t idx_start, uint8_t idx_end,
+ LLVMValueRef r,
+ LLVMBasicBlockRef in, LLVMBasicBlockRef yes, LLVMBasicBlockRef no) {
+ if (!cs) return false;
+ if (idx_start > idx_end) return false;
+
+ /*
+ * Scan the range of indices, and for each thing in the charset,
+ * compare and conditional branch.
+ */
+ LLVMPositionBuilderAtEnd(builder, in);
+
+ for (int i = idx_start; i <= idx_end; ++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);
+
+ return true;
+}
+
+/*
+ * Turn an llvm_charset_exec_plan_t into IR
+ */
+
+static bool h_llvm_cep_to_ir(HAllocator* mm__,
+ LLVMModuleRef mod, LLVMValueRef func, LLVMBuilderRef builder,
+ LLVMValueRef r, llvm_charset_exec_plan_t *cep,
+ LLVMBasicBlockRef in, LLVMBasicBlockRef yes, LLVMBasicBlockRef no) {
+ bool rv;
+
+ if (!cep) return false;
+
+ switch (cep->action) {
+ case CHARSET_ACTION_SCAN:
+ rv = h_llvm_build_ir_for_scan(mod, func, builder,
+ cep->cs, cep->idx_start, cep->idx_end, r, in, yes, no);
+ break;
+ case CHARSET_ACTION_ACCEPT:
+ /* Easy case; just unconditionally branch to the yes output */
+ LLVMPositionBuilderAtEnd(builder, in);
+ LLVMBuildBr(builder, yes);
+ break;
+ case CHARSET_ACTION_BITMAP:
+#ifdef HAMMER_LLVM_CHARSET_DEBUG
+ fprintf(stderr,
+ "CHARSET_ACTION_BITMAP not yet implemented (cep %p)\n",
+ (void *)cep);
+#endif /* defined(HAMMER_LLVM_CHARSET_DEBUG) */
+ rv = false;
+ break;
+ case CHARSET_ACTION_COMPLEMENT:
+ /* This is trivial; just swap the 'yes' and 'no' outputs and build the child */
+ rv = h_llvm_cep_to_ir(mm__, mod, func, builder, r, cep->children[0], in, no, yes);
+ break;
+ case CHARSET_ACTION_SPLIT:
+#ifdef HAMMER_LLVM_CHARSET_DEBUG
+ fprintf(stderr,
+ "CHARSET_ACTION_SPLIT not yet implemented (cep %p)\n",
+ (void *)cep);
+#endif /* defined(HAMMER_LLVM_CHARSET_DEBUG) */
+ rv = false;
+ break;
+ default:
+ /* Unknown action type */
+#ifdef HAMMER_LLVM_CHARSET_DEBUG
+ fprintf(stderr,
+ "cep %p has unknown action type\n",
+ (void *)cep);
+#endif /* defined(HAMMER_LLVM_CHARSET_DEBUG) */
+ rv = false;
+ break;
+ }
+
+ return rv;
+}
+
/*
* Construct LLVM IR to decide if a runtime value is a member of a compile-time
* character set, and branch depending on the result.
@@ -802,9 +899,11 @@ static void h_llvm_pretty_print_charset_exec_plan(HAllocator *mm__, llvm_charset
* - 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
+ *
+ * Returns: true on success, false on failure
*/
-void h_llvm_make_charset_membership_test(HAllocator* mm__,
+bool h_llvm_make_charset_membership_test(HAllocator* mm__,
LLVMModuleRef mod, LLVMValueRef func, LLVMBuilderRef builder,
LLVMValueRef r, HCharset cs,
LLVMBasicBlockRef yes, LLVMBasicBlockRef no) {
@@ -818,38 +917,47 @@ void h_llvm_make_charset_membership_test(HAllocator* mm__,
* 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.
+ * We achieve this by building a tree of actions to minimize a cost metric,
+ * and then transforming the tree into IR.
*/
+ bool rv;
+
/* 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 {
+ if (!cep) {
fprintf(stderr, "got null from h_llvm_build_charset_exec_plan()\n");
+ return false;
}
- 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);
- }
+#ifdef HAMMER_LLVM_CHARSET_DEBUG
+ 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);
+ if (!ok) {
+ fprintf(stderr, "h_llvm_make_charset_membership_test() error-exiting "
+ "because consistency check failed\n");
+ h_llvm_free_charset_exec_plan(mm__, cep);
+ cep = NULL;
+ return false;
}
+#endif /* defined(HAMMER_LLVM_CHARSET_DEBUG) */
- LLVMBuildBr(builder, no);
+ /* Create input block */
+ LLVMBasicBlockRef start = LLVMAppendBasicBlock(func, "cs_start");
+ /*
+ * Make unconditional branch into input block from wherever our caller
+ * had us positioned.
+ */
+ LLVMBuildBr(builder, start);
+
+ rv = h_llvm_cep_to_ir(mm__, mod, func, builder, r, cep, start, yes, no);
+
+ h_llvm_free_charset_exec_plan(mm__, cep);
+ cep = NULL;
+
+ return rv;
}
#endif /* defined(HAMMER_LLVM_BACKEND) */
diff --git a/src/parsers/charset.c b/src/parsers/charset.c
index 741adcd8..5870fc2c 100644
--- a/src/parsers/charset.c
+++ b/src/parsers/charset.c
@@ -85,6 +85,7 @@ static bool cs_llvm(HAllocator *mm__, LLVMBuilderRef builder, LLVMValueRef func,
* LLVM to build a function to parse a charset; the args are a stream and an
* arena.
*/
+ bool ok;
LLVMValueRef stream = LLVMGetFirstParam(func);
stream = LLVMBuildBitCast(builder, stream, llvm_inputstreamptr, "stream");
@@ -109,7 +110,7 @@ static bool cs_llvm(HAllocator *mm__, LLVMBuilderRef builder, LLVMValueRef func,
/* We have a char, need to check if it's in the charset */
HCharset cs = (HCharset)env;
/* Branch to either success or end, conditional on whether r is in cs */
- h_llvm_make_charset_membership_test(mm__, mod, func, builder, r, cs, success, fail);
+ ok = h_llvm_make_charset_membership_test(mm__, mod, func, builder, r, cs, success, fail);
/* Basic block: success */
LLVMPositionBuilderAtEnd(builder, success);
@@ -145,7 +146,7 @@ static bool cs_llvm(HAllocator *mm__, LLVMBuilderRef builder, LLVMValueRef func,
// ret %struct.HParseResult_.3* %rv
LLVMBuildRet(builder, rv);
- return true;
+ return ok;
}
#endif /* defined(HAMMER_LLVM_BACKEND) */
--
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