support pre-assigning indexes for functions that are called indirectly

src/s2wasm.h

@@ -639,6 +639,13 @@ class S2WasmBuilder {
         }
       } else if (match(".result")) {
         resultType = getType();
+      } else if (match(".indidx")) {
+        int64_t indirectIndex = getInt64();
+        skipWhitespace();
+        if (indirectIndex < 0) {
+          abort_on("indidx");
+        }
+        linkerObj->addIndirectIndex(name, indirectIndex);
       } else if (match(".local")) {
         while (1) {
           Name name = getNextId();

src/wasm-linker.h

@@ -159,6 +159,11 @@ class LinkerObject {
     return f->second;
   }
 
+  void addIndirectIndex(Name name, uint64_t index) {
+    assert(!indirect_indexes.count(name));
+    indirect_indexes[name] = index;
+  }
+
   bool isEmpty() {
     return wasm.functions.empty();
   }
@@ -192,6 +197,8 @@ class LinkerObject {
   std::map<Name, Address> segments; // name => segment index (in wasm module)
   std::map<Index, Table *> tables; // index => table index (in wasm module)
 
+  std::map<Name, uint64_t> indirect_indexes;
+
   std::vector<Name> initializerFunctions;
 
   LinkerObject(const LinkerObject&) = delete;
@@ -328,7 +335,8 @@ class Linker {
 
   std::unordered_map<cashew::IString, int32_t> staticAddresses; // name => address
   std::unordered_map<Address, Address> segmentsByAddress; // address => segment index
-  std::unordered_map<cashew::IString, std::pair<Index, Index>> functionIndexes; // name => table, entry indexes
+  std::unordered_map<cashew::IString, std::pair<Index, uint64_t>> functionIndexes; // name => table, entry indexes
+  std::map<uint64_t, cashew::IString> functionNames;
 };
 
 

test/dot_s/indidx.s

@@ -0,0 +1,93 @@
+	.text
+	.file	"cfi-wasm.bs.bc"
+	.type	a,@function
+a:                                      # @a
+	.indidx  	0
+	.result 	i32
+# BB#0:                                 # %entry
+	i32.const	$push0=, 0
+                                        # fallthrough-return: $pop0
+	.endfunc
+.Lfunc_end0:
+	.size	a, .Lfunc_end0-a
+
+	.type	b,@function
+b:                                      # @b
+	.indidx  	1
+	.result 	i32
+# BB#0:                                 # %entry
+	i32.const	$push0=, 1
+                                        # fallthrough-return: $pop0
+	.endfunc
+.Lfunc_end1:
+	.size	b, .Lfunc_end1-b
+
+	.type	c,@function
+c:                                      # @c
+	.indidx  	2
+	.result 	i32
+# BB#0:                                 # %entry
+	i32.const	$push0=, 2
+                                        # fallthrough-return: $pop0
+	.endfunc
+.Lfunc_end2:
+	.size	c, .Lfunc_end2-c
+
+	.type	d,@function
+d:                                      # @d
+	.indidx  	3
+	.result 	i32
+# BB#0:                                 # %entry
+	i32.const	$push0=, 3
+                                        # fallthrough-return: $pop0
+	.endfunc
+.Lfunc_end3:
+	.size	d, .Lfunc_end3-d
+
+	.hidden	main
+	.globl	main
+	.type	main,@function
+main:                                   # @main
+	.param  	i32, i32
+	.result 	i32
+	.local  	i32
+# BB#0:                                 # %entry
+	block
+	i32.call	$push1=, getchar@FUNCTION
+	i32.const	$push0=, 2
+	i32.shl 	$push2=, $pop1, $pop0
+	i32.const	$push3=, .Lmain.fp-192
+	i32.add 	$push4=, $pop2, $pop3
+	i32.load	$push9=, 0($pop4)
+	tee_local	$push8=, $2=, $pop9
+	i32.const	$push5=, 4
+	i32.ge_u	$push6=, $pop8, $pop5
+	br_if   	0, $pop6        # 0: down to label0
+# BB#1:                                 # %cont
+	i32.call_indirect	$push7=, $2
+	return  	$pop7
+.LBB4_2:                                # %trap
+	end_block                       # label0:
+	unreachable
+	unreachable
+	.endfunc
+.Lfunc_end4:
+	.size	main, .Lfunc_end4-main
+
+	.type	.Lmain.fp,@object       # @main.fp
+	.section	.data.rel.ro,"aw",@progbits
+	.p2align	4
+.Lmain.fp:
+	.int32	a@FUNCTION
+	.int32	b@FUNCTION
+	.int32	c@FUNCTION
+	.int32	d@FUNCTION
+	.size	.Lmain.fp, 16
+
+	.type	.L__unnamed_1,@object   # @0
+	.section	.rodata,"a",@progbits
+.L__unnamed_1:
+	.size	.L__unnamed_1, 0
+
+
+	.ident	"clang version 3.9.0 (trunk 271314) (llvm/trunk 271322)"

test/dot_s/indidx.wast

@@ -0,0 +1,57 @@
+(module
+  (memory 1
+    (segment 16 "\00\00\00\00\01\00\00\00\02\00\00\00\03\00\00\00")
+  )
+  (export "memory" memory)
+  (type $FUNCSIG$i (func (result i32)))
+  (import $getchar "env" "getchar" (result i32))
+  (export "main" $main)
+  (export "dynCall_i" $dynCall_i)
+  (table $a $b $c $d)
+  (func $a (type $FUNCSIG$i) (result i32)
+    (i32.const 0)
+  )
+  (func $b (type $FUNCSIG$i) (result i32)
+    (i32.const 1)
+  )
+  (func $c (type $FUNCSIG$i) (result i32)
+    (i32.const 2)
+  )
+  (func $d (type $FUNCSIG$i) (result i32)
+    (i32.const 3)
+  )
+  (func $main (param $0 i32) (param $1 i32) (result i32)
+    (local $2 i32)
+    (block $label$0
+      (br_if $label$0
+        (i32.ge_u
+          (set_local $2
+            (i32.load
+              (i32.add
+                (i32.shl
+                  (call_import $getchar)
+                  (i32.const 2)
+                )
+                (i32.const -176)
+              )
+            )
+          )
+          (i32.const 4)
+        )
+      )
+      (return
+        (call_indirect $FUNCSIG$i
+          (get_local $2)
+        )
+      )
+    )
+    (unreachable)
+    (unreachable)
+  )
+  (func $dynCall_i (param $fptr i32) (result i32)
+    (call_indirect $FUNCSIG$i
+      (get_local $fptr)
+    )
+  )
+)
+;; METADATA: { "asmConsts": {},"staticBump": 32, "initializers": [] }