Avoid unnecessary fp$ in side modules (#2717)

Now that we update the dylink section properly, we can
do the same optimization in side modules as in main ones:
if the module provides a function, don't call an $fp method
during startup, instead add it to the table ourselves and use
the relative offset to the table base.

Fix an issue when the table has no segments initially: the
code just added an offset of 0, but that's not right. Instead,
an a __table_base import and use that as the offset. As
this is ABI-specific I did it on wasm-emscripten-finalize,
leaving TableUtils to just assert on having a singleton
segment.

Add a test of a wasm file with a dylink section to the lld tests.

6 files changed, 181 insertions, 21 deletions

diff --git a/test/lld/main_module_table.wat.out b/test/lld/main_module_table.wat.out
index fd292809f..412d1715f 100644
--- a/test/lld/main_module_table.wat.out
+++ b/test/lld/main_module_table.wat.out
@@ -4,8 +4,9 @@
  (type $i32_=>_i32 (func (param i32) (result i32)))
  (type $none_=>_i32 (func (result i32)))
  (import "env" "__stack_pointer" (global $sp_import i32))
+ (import "env" "__table_base" (global $__table_base i32))
  (table $0 1 funcref)
- (elem (i32.const 0) $__stdio_write)
+ (elem (global.get $__table_base) $__stdio_write)
  (global $gimport$9 (mut i32) (i32.const 0))
  (global $global i32 (i32.const 42))
  (global $sp (mut i32) (global.get $sp_import))
@@ -51,7 +52,7 @@
  (func $__assign_got_enties (; 5 ;)
   (global.set $gimport$9
    (i32.add
-    (i32.const 0)
+    (global.get $__table_base)
     (i32.const 0)
    )
   )
@@ -73,7 +74,8 @@
   "declares": [
   ],
   "externs": [
-    "___stack_pointer"
+    "___stack_pointer",
+    "___table_base"
   ],
   "implementedFunctions": [
     "___stdio_write",
diff --git a/test/lld/main_module_table_2.wat.out b/test/lld/main_module_table_2.wat.out
index 92a40d5f2..1dd833150 100644
--- a/test/lld/main_module_table_2.wat.out
+++ b/test/lld/main_module_table_2.wat.out
@@ -4,8 +4,9 @@
  (type $i32_=>_i32 (func (param i32) (result i32)))
  (type $none_=>_i32 (func (result i32)))
  (import "env" "table" (table $0 2 funcref))
- (elem (i32.const 0) $__stdio_write)
+ (elem (global.get $__table_base) $__stdio_write)
  (import "env" "__stack_pointer" (global $sp_import i32))
+ (import "env" "__table_base" (global $__table_base i32))
  (global $gimport$9 (mut i32) (i32.const 0))
  (global $global i32 (i32.const 42))
  (global $sp (mut i32) (global.get $sp_import))
@@ -51,7 +52,7 @@
  (func $__assign_got_enties (; 5 ;)
   (global.set $gimport$9
    (i32.add
-    (i32.const 0)
+    (global.get $__table_base)
     (i32.const 0)
    )
   )
@@ -73,7 +74,8 @@
   "declares": [
   ],
   "externs": [
-    "___stack_pointer"
+    "___stack_pointer",
+    "___table_base"
   ],
   "implementedFunctions": [
     "___stdio_write",
diff --git a/test/lld/main_module_table_3.wat.out b/test/lld/main_module_table_3.wat.out
index 92a40d5f2..f48ab6216 100644
--- a/test/lld/main_module_table_3.wat.out
+++ b/test/lld/main_module_table_3.wat.out
@@ -6,6 +6,7 @@
  (import "env" "table" (table $0 2 funcref))
  (elem (i32.const 0) $__stdio_write)
  (import "env" "__stack_pointer" (global $sp_import i32))
+ (import "env" "__table_base" (global $__table_base i32))
  (global $gimport$9 (mut i32) (i32.const 0))
  (global $global i32 (i32.const 42))
  (global $sp (mut i32) (global.get $sp_import))
@@ -51,7 +52,7 @@
  (func $__assign_got_enties (; 5 ;)
   (global.set $gimport$9
    (i32.add
-    (i32.const 0)
+    (global.get $__table_base)
     (i32.const 0)
    )
   )
@@ -73,7 +74,8 @@
   "declares": [
   ],
   "externs": [
-    "___stack_pointer"
+    "___stack_pointer",
+    "___table_base"
   ],
   "implementedFunctions": [
     "___stdio_write",
diff --git a/test/lld/shared.wat.out b/test/lld/shared.wat.out
index 5cc1cf88f..64f97b984 100644
--- a/test/lld/shared.wat.out
+++ b/test/lld/shared.wat.out
@@ -4,13 +4,13 @@
  (type $i32_=>_i32 (func (param i32) (result i32)))
  (import "env" "memory" (memory $0 0))
  (data (global.get $gimport$2) "Hello, world\00\00\00\00\00\00\00\00\00\00\00\00")
- (import "env" "table" (table $0 0 funcref))
+ (import "env" "table" (table $0 1 funcref))
+ (elem (global.get $gimport$3) $print_message\28\29)
  (import "env" "__memory_base" (global $gimport$2 i32))
  (import "env" "__table_base" (global $gimport$3 i32))
  (import "env" "puts" (func $puts (param i32) (result i32)))
  (import "env" "g$external_var" (func $g$external_var (result i32)))
  (import "env" "fp$puts$ii" (func $fp$puts$ii (result i32)))
- (import "env" "fp$_Z13print_messagev$i" (func $fp$_Z13print_messagev$i (result i32)))
  (global $gimport$5 (mut i32) (i32.const 0))
  (global $gimport$6 (mut i32) (i32.const 0))
  (global $gimport$7 (mut i32) (i32.const 0))
@@ -20,10 +20,11 @@
  (export "ptr_puts" (global $global$0))
  (export "ptr_local_func" (global $global$1))
  (export "__post_instantiate" (func $__post_instantiate))
- (func $__wasm_call_ctors (; 4 ;)
+ (export "dynCall_i" (func $dynCall_i))
+ (func $__wasm_call_ctors (; 3 ;)
   (call $__wasm_apply_relocs)
  )
- (func $__wasm_apply_relocs (; 5 ;)
+ (func $__wasm_apply_relocs (; 4 ;)
   (i32.store
    (i32.add
     (global.get $gimport$2)
@@ -39,7 +40,7 @@
    (global.get $gimport$7)
   )
  )
- (func $print_message\28\29 (; 6 ;) (result i32)
+ (func $print_message\28\29 (; 5 ;) (result i32)
   (drop
    (call $puts
     (i32.add
@@ -52,11 +53,11 @@
    (global.get $gimport$5)
   )
  )
- (func $__post_instantiate (; 7 ;)
+ (func $__post_instantiate (; 6 ;)
   (call $__assign_got_enties)
   (call $__wasm_call_ctors)
  )
- (func $__assign_got_enties (; 8 ;)
+ (func $__assign_got_enties (; 7 ;)
   (global.set $gimport$5
    (call $g$external_var)
   )
@@ -64,7 +65,15 @@
    (call $fp$puts$ii)
   )
   (global.set $gimport$7
-   (call $fp$_Z13print_messagev$i)
+   (i32.add
+    (global.get $gimport$3)
+    (i32.const 0)
+   )
+  )
+ )
+ (func $dynCall_i (; 8 ;) (param $fptr i32) (result i32)
+  (call_indirect (type $none_=>_i32)
+   (local.get $fptr)
   )
  )
 )
@@ -72,12 +81,11 @@
 --BEGIN METADATA --
 {
   "staticBump": 0,
-  "tableSize": 0,
+  "tableSize": 1,
   "declares": [
     "puts",
     "g$external_var",
-    "fp$puts$ii",
-    "fp$_Z13print_messagev$i"
+    "fp$puts$ii"
   ],
   "externs": [
     "___memory_base",
@@ -85,11 +93,13 @@
   ],
   "implementedFunctions": [
     "__Z13print_messagev",
-    "___post_instantiate"
+    "___post_instantiate",
+    "_dynCall_i"
   ],
   "exports": [
     "_Z13print_messagev",
-    "__post_instantiate"
+    "__post_instantiate",
+    "dynCall_i"
   ],
   "namedGlobals": {
     "ptr_puts" : "16",
diff --git a/test/lld/shared_add_to_table.wasm b/test/lld/shared_add_to_table.wasm
new file mode 100644
index 000000000..00ea9f906
--- /dev/null
+++ b/test/lld/shared_add_to_table.wasm
diff --git a/test/lld/shared_add_to_table.wasm.out b/test/lld/shared_add_to_table.wasm.out
new file mode 100644
index 000000000..c561a89d3
--- /dev/null
+++ b/test/lld/shared_add_to_table.wasm.out
@@ -0,0 +1,144 @@
+(module
+ (type $none_=>_none (func))
+ (type $none_=>_i32 (func (result i32)))
+ (type $i32_=>_i32 (func (param i32) (result i32)))
+ (type $i32_i32_=>_i32 (func (param i32 i32) (result i32)))
+ (import "env" "memory" (memory $0 0))
+ (data (global.get $gimport$3) "*\00\00\00")
+ (import "env" "table" (table $timport$1 1 funcref))
+ (elem (global.get $gimport$4) $waka_func_mine\28int\29)
+ (import "env" "__memory_base" (global $gimport$3 i32))
+ (import "env" "__table_base" (global $gimport$4 i32))
+ (import "env" "_Z16waka_func_theirsi" (func $waka_func_theirs\28int\29 (param i32) (result i32)))
+ (import "env" "g$waka_mine" (func $g$waka_mine (result i32)))
+ (import "env" "g$waka_others" (func $g$waka_others (result i32)))
+ (import "env" "fp$_Z16waka_func_theirsi$ii" (func $fp$_Z16waka_func_theirsi$ii (result i32)))
+ (global $gimport$6 (mut i32) (i32.const 0))
+ (global $gimport$7 (mut i32) (i32.const 0))
+ (global $gimport$8 (mut i32) (i32.const 0))
+ (global $gimport$9 (mut i32) (i32.const 0))
+ (global $global$0 i32 (i32.const 0))
+ (global $global$1 i32 (i32.const 0))
+ (export "__wasm_apply_relocs" (func $__wasm_apply_relocs))
+ (export "_Z14waka_func_minei" (func $waka_func_mine\28int\29))
+ (export "__original_main" (func $__original_main))
+ (export "waka_mine" (global $global$0))
+ (export "main" (func $main))
+ (export "__dso_handle" (global $global$1))
+ (export "__post_instantiate" (func $__post_instantiate))
+ (export "dynCall_ii" (func $dynCall_ii))
+ (func $__wasm_call_ctors (; 4 ;)
+  (call $__wasm_apply_relocs)
+ )
+ (func $__wasm_apply_relocs (; 5 ;)
+ )
+ (func $waka_func_mine\28int\29 (; 6 ;) (param $0 i32) (result i32)
+  (i32.add
+   (local.get $0)
+   (i32.const 1)
+  )
+ )
+ (func $__original_main (; 7 ;) (result i32)
+  (local $0 i32)
+  (local $1 i32)
+  (local.set $0
+   (global.get $gimport$6)
+  )
+  (local.set $1
+   (global.get $gimport$7)
+  )
+  (i32.add
+   (i32.add
+    (i32.load
+     (global.get $gimport$8)
+    )
+    (i32.add
+     (local.get $1)
+     (local.get $0)
+    )
+   )
+   (i32.load
+    (global.get $gimport$9)
+   )
+  )
+ )
+ (func $main (; 8 ;) (param $0 i32) (param $1 i32) (result i32)
+  (call $__original_main)
+ )
+ (func $__post_instantiate (; 9 ;)
+  (call $__assign_got_enties)
+  (call $__wasm_call_ctors)
+ )
+ (func $__assign_got_enties (; 10 ;)
+  (global.set $gimport$8
+   (call $g$waka_mine)
+  )
+  (global.set $gimport$9
+   (call $g$waka_others)
+  )
+  (global.set $gimport$6
+   (call $fp$_Z16waka_func_theirsi$ii)
+  )
+  (global.set $gimport$7
+   (i32.add
+    (global.get $gimport$4)
+    (i32.const 0)
+   )
+  )
+ )
+ (func $dynCall_ii (; 11 ;) (param $fptr i32) (param $0 i32) (result i32)
+  (call_indirect (type $i32_=>_i32)
+   (local.get $0)
+   (local.get $fptr)
+  )
+ )
+ ;; dylink section
+ ;;   memorysize: 4
+ ;;   memoryalignment: 2
+ ;;   tablesize: 1
+ ;;   tablealignment: 0
+ ;; custom section "producers", size 157
+)
+(;
+--BEGIN METADATA --
+{
+  "staticBump": 0,
+  "tableSize": 1,
+  "declares": [
+    "_Z16waka_func_theirsi",
+    "g$waka_mine",
+    "g$waka_others",
+    "fp$_Z16waka_func_theirsi$ii"
+  ],
+  "externs": [
+    "___memory_base",
+    "___table_base"
+  ],
+  "implementedFunctions": [
+    "___wasm_apply_relocs",
+    "__Z14waka_func_minei",
+    "___original_main",
+    "_main",
+    "___post_instantiate",
+    "_dynCall_ii"
+  ],
+  "exports": [
+    "__wasm_apply_relocs",
+    "_Z14waka_func_minei",
+    "__original_main",
+    "main",
+    "__post_instantiate",
+    "dynCall_ii"
+  ],
+  "namedGlobals": {
+    "waka_mine" : "0",
+    "__dso_handle" : "0"
+  },
+  "invokeFuncs": [
+  ],
+  "features": [
+  ],
+  "mainReadsParams": 0
+}
+-- END METADATA --
+;)