Add offset parameter to BinaryenSetFunctionTable (#2380)

This PR adds an offset parameter to BinaryenSetFunctionTable so table elements
can start at the value of an (imported constant) global. Previously, the offset
was fixed to zero. As usual this is a breaking change to the C-API but backwards
compatible when using the JS-API.

Author: dcodeIO

CHANGELOG.md

@@ -26,6 +26,7 @@ Current Trunk
 - Added `mutable` parameter to BinaryenAddGlobalImport.
 - Replace BinaryenSIMDBitselect* with BinaryenSIMDTernary* in the C API and add
   qfma/qfms instructions.
+- Added `offset` parameter to BinaryenSetFunctionTable.
 
 v88
 ---

src/binaryen-c.cpp

@@ -3449,7 +3449,8 @@ void BinaryenSetFunctionTable(BinaryenModuleRef module,
                               BinaryenIndex initial,
                               BinaryenIndex maximum,
                               const char** funcNames,
-                              BinaryenIndex numFuncNames) {
+                              BinaryenIndex numFuncNames,
+                              BinaryenExpressionRef offset) {
   if (tracing) {
     std::cout << "  {\n";
     std::cout << "    const char* funcNames[] = { ";
@@ -3461,13 +3462,13 @@ void BinaryenSetFunctionTable(BinaryenModuleRef module,
     }
     std::cout << " };\n";
     std::cout << "    BinaryenSetFunctionTable(the_module, " << initial << ", "
-              << maximum << ", funcNames, " << numFuncNames << ");\n";
+              << maximum << ", funcNames, " << numFuncNames << ", expressions["
+              << expressions[offset] << "]);\n";
     std::cout << "  }\n";
   }
 
   auto* wasm = (Module*)module;
-  Table::Segment segment(
-    wasm->allocator.alloc<Const>()->set(Literal(int32_t(0))));
+  Table::Segment segment((Expression*)offset);
   for (BinaryenIndex i = 0; i < numFuncNames; i++) {
     segment.data.push_back(funcNames[i]);
   }

src/binaryen-c.h

@@ -1144,7 +1144,8 @@ BINARYEN_API void BinaryenSetFunctionTable(BinaryenModuleRef module,
                                            BinaryenIndex initial,
                                            BinaryenIndex maximum,
                                            const char** funcNames,
-                                           BinaryenIndex numFuncNames);
+                                           BinaryenIndex numFuncNames,
+                                           BinaryenExpressionRef offset);
 
 // Memory. One per module
 

src/js/binaryen.js-post.js

@@ -2056,11 +2056,12 @@ function wrapModule(module, self) {
       return Module['_BinaryenRemoveExport'](module, strToStack(externalName));
     });
   };
-  self['setFunctionTable'] = function(initial, maximum, funcNames) {
+  self['setFunctionTable'] = function(initial, maximum, funcNames, offset) {
     return preserveStack(function() {
       return Module['_BinaryenSetFunctionTable'](module, initial, maximum,
         i32sToStack(funcNames.map(strToStack)),
-        funcNames.length
+        funcNames.length,
+        offset || self['i32']['const'](0)
       );
     });
   };

test/binaryen.js/kitchen-sink.js.txt

@@ -5471,28 +5471,29 @@ getExpressionInfo(f64.const)={"id":14,"type":4,"value":9.5}
   BinaryenFunctionGetVar(functions[0], 0);
   BinaryenFunctionGetVar(functions[0], 1);
   BinaryenFunctionGetBody(functions[0]);
+  expressions[777] = BinaryenConst(the_module, BinaryenLiteralInt32(0));
   {
     const char* funcNames[] = { "kitchen()sinker" };
-    BinaryenSetFunctionTable(the_module, 1, 4294967295, funcNames, 1);
+    BinaryenSetFunctionTable(the_module, 1, 4294967295, funcNames, 1, expressions[777]);
   }
-  expressions[777] = BinaryenConst(the_module, BinaryenLiteralInt32(10));
+  expressions[778] = BinaryenConst(the_module, BinaryenLiteralInt32(10));
   {
     const char segment0[] = { 104, 101, 108, 108, 111, 44, 32, 119, 111, 114, 108, 100 };
     const char segment1[] = { 73, 32, 97, 109, 32, 112, 97, 115, 115, 105, 118, 101 };
     const char* segments[] = { segment0, segment1 };
     int8_t segmentPassive[] = { 0, 1 };
-    BinaryenExpressionRef segmentOffsets[] = { expressions[777], expressions[0] };
+    BinaryenExpressionRef segmentOffsets[] = { expressions[778], expressions[0] };
     BinaryenIndex segmentSizes[] = { 12, 12 };
     BinaryenSetMemory(the_module, 1, 256, "mem", segments, segmentPassive, segmentOffsets, segmentSizes, 2, 1);
   }
   {
     BinaryenType paramTypes[] = { 0 };
     functionTypes[3] = BinaryenAddFunctionType(the_module, "v", 0, paramTypes, 0);
   }
-  expressions[778] = BinaryenNop(the_module);
+  expressions[779] = BinaryenNop(the_module);
   {
     BinaryenType varTypes[] = { 0 };
-    functions[1] = BinaryenAddFunction(the_module, "starter", functionTypes[3], varTypes, 0, expressions[778]);
+    functions[1] = BinaryenAddFunction(the_module, "starter", functionTypes[3], varTypes, 0, expressions[779]);
   }
   BinaryenSetStart(the_module, functions[1]);
   {

test/binaryen.js/reloc.js

@@ -0,0 +1,26 @@
+function assert(x) {
+  if (!x) throw 'error!';
+}
+
+var module = new Binaryen.Module();
+
+// memory with offset
+
+module.addGlobalImport("memory_base", "env", "memory_base", Binaryen.i32, false);
+module.setMemory(1, -1, null, [
+  {
+    offset: module.global.get("memory_base", Binaryen.i32),
+    data: "data data".split('').map(function(x) { return x.charCodeAt(0) })
+  }
+]);
+
+// table with offset
+
+var signature = module.addFunctionType("v", Binaryen.none, []);
+var func = module.addFunction("func", signature, [], module.nop());
+
+module.addGlobalImport("table_base", "env", "table_base", Binaryen.i32, false);
+module.setFunctionTable(1, -1, [ "func", "func" ], module.global.get("table_base", Binaryen.i32));
+
+assert(module.validate());
+console.log(module.emitText());

test/binaryen.js/reloc.js.txt

@@ -0,0 +1,13 @@
+(module
+ (type $v (func))
+ (import "env" "memory_base" (global $memory_base i32))
+ (import "env" "table_base" (global $table_base i32))
+ (memory $0 1)
+ (data (global.get $memory_base) "data data")
+ (table $0 1 funcref)
+ (elem (global.get $table_base) $func $func)
+ (func $func (; 0 ;) (type $v)
+  (nop)
+ )
+)
+

test/example/c-api-kitchen-sink.c

@@ -637,7 +637,7 @@ void test_core() {
 
   // Function table. One per module
   const char* funcNames[] = { BinaryenFunctionGetName(sinker) };
-  BinaryenSetFunctionTable(module, 1, 1, funcNames, 1);
+  BinaryenSetFunctionTable(module, 1, 1, funcNames, 1, BinaryenConst(module, BinaryenLiteralInt32(0)));
 
   // Memory. One per module
 

test/example/c-api-kitchen-sink.txt

@@ -3771,28 +3771,29 @@ int main() {
   BinaryenAddFunctionImport(the_module, "an-imported", "module", "base", functionTypes[2]);
   exports[0] = BinaryenAddFunctionExport(the_module, "kitchen()sinker", "kitchen_sinker");
   BinaryenFunctionGetName(functions[0]);
+  expressions[758] = BinaryenConst(the_module, BinaryenLiteralInt32(0));
   {
     const char* funcNames[] = { "kitchen()sinker" };
-    BinaryenSetFunctionTable(the_module, 1, 1, funcNames, 1);
+    BinaryenSetFunctionTable(the_module, 1, 1, funcNames, 1, expressions[758]);
   }
-  expressions[758] = BinaryenConst(the_module, BinaryenLiteralInt32(10));
+  expressions[759] = BinaryenConst(the_module, BinaryenLiteralInt32(10));
   {
     const char segment0[] = { 104, 101, 108, 108, 111, 44, 32, 119, 111, 114, 108, 100 };
     const char segment1[] = { 73, 32, 97, 109, 32, 112, 97, 115, 115, 105, 118, 101 };
     const char* segments[] = { segment0, segment1 };
     int8_t segmentPassive[] = { 0, 1 };
-    BinaryenExpressionRef segmentOffsets[] = { expressions[758], expressions[0] };
+    BinaryenExpressionRef segmentOffsets[] = { expressions[759], expressions[0] };
     BinaryenIndex segmentSizes[] = { 12, 12 };
     BinaryenSetMemory(the_module, 1, 256, "mem", segments, segmentPassive, segmentOffsets, segmentSizes, 2, 1);
   }
   {
     BinaryenType paramTypes[] = { 0 };
     functionTypes[3] = BinaryenAddFunctionType(the_module, "v", 0, paramTypes, 0);
   }
-  expressions[759] = BinaryenNop(the_module);
+  expressions[760] = BinaryenNop(the_module);
   {
     BinaryenType varTypes[] = { 0 };
-    functions[1] = BinaryenAddFunction(the_module, "starter", functionTypes[3], varTypes, 0, expressions[759]);
+    functions[1] = BinaryenAddFunction(the_module, "starter", functionTypes[3], varTypes, 0, expressions[760]);
   }
   BinaryenSetStart(the_module, functions[1]);
   {