[lld][WebAssembly] Fix for --import-table when combined with reference types #97451
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
|
@llvm/pr-subscribers-lld Author: Sam Clegg (sbc100) ChangesWhen reference types are enabled clang will generate call_indirect instructions that explicitly reference the global In this case the resulting global symbol was not being correctly marked with explicit import name/module, resulting in the linker reporting errors when it was referenced. This issue was reported in WebAssembly/tool-conventions#158 Full diff: https://github.com/llvm/llvm-project/pull/97451.diff 3 Files Affected:
diff --git a/lld/test/wasm/import-table-explicit.s b/lld/test/wasm/import-table-explicit.s
new file mode 100644
index 0000000000000..1dc21beba0629
--- /dev/null
+++ b/lld/test/wasm/import-table-explicit.s
@@ -0,0 +1,26 @@
+# RUN: llvm-mc -mattr=+reference-types -filetype=obj -triple=wasm32-unknown-unknown %s -o %t.o
+# RUN: wasm-ld --import-table -o %t.wasm %t.o
+# RUN: obj2yaml %t.wasm | FileCheck %s
+
+.globl __indirect_function_table
+.tabletype __indirect_function_table, funcref
+
+.globl _start
+_start:
+ .functype _start () -> ()
+ i32.const 1
+ call_indirect __indirect_function_table, () -> ()
+ end_function
+
+# Verify the --import-table flag creates a table import
+
+# CHECK: - Type: IMPORT
+# CHECK-NEXT: Imports:
+# CHECK-NEXT: - Module: env
+# CHECK-NEXT: Field: __indirect_function_table
+# CHECK-NEXT: Kind: TABLE
+# CHECK-NEXT: Table:
+# CHECK-NEXT: Index: 0
+# CHECK-NEXT: ElemType: FUNCREF
+# CHECK-NEXT: Limits:
+# CHECK-NEXT: Minimum: 0x1
diff --git a/lld/test/wasm/import-table.test b/lld/test/wasm/import-table.s
similarity index 63%
rename from lld/test/wasm/import-table.test
rename to lld/test/wasm/import-table.s
index 73dc7189bbf28..7a0c94d130276 100644
--- a/lld/test/wasm/import-table.test
+++ b/lld/test/wasm/import-table.s
@@ -1,14 +1,14 @@
-# RUN: llvm-mc -filetype=obj -triple=wasm32-unknown-unknown %p/Inputs/start.s -o %t.start.o
# RUN: llvm-mc -filetype=obj -triple=wasm32-unknown-unknown %s -o %t.o
-# RUN: wasm-ld --export-all --import-table -o %t.wasm %t.start.o %t.o
+# RUN: wasm-ld --export-all --import-table -o %t.wasm %t.o
# RUN: obj2yaml %t.wasm | FileCheck %s
-.globl require_function_table
-require_function_table:
-.functype require_function_table () -> ()
- i32.const 1
- call_indirect () -> ()
- end_function
+.globl _start
+_start:
+ .functype _start () -> ()
+ i32.const 1
+ # call_indirect instruction implicitly references the function table
+ call_indirect () -> ()
+ end_function
# Verify the --import-table flag creates a table import
diff --git a/lld/wasm/SymbolTable.cpp b/lld/wasm/SymbolTable.cpp
index 00c347ea3ef24..09c463299b05c 100644
--- a/lld/wasm/SymbolTable.cpp
+++ b/lld/wasm/SymbolTable.cpp
@@ -681,10 +681,9 @@ TableSymbol *SymbolTable::createUndefinedIndirectFunctionTable(StringRef name) {
WasmTableType *type = make<WasmTableType>();
type->ElemType = ValType::FUNCREF;
type->Limits = limits;
- StringRef module(defaultModule);
uint32_t flags = config->exportTable ? 0 : WASM_SYMBOL_VISIBILITY_HIDDEN;
flags |= WASM_SYMBOL_UNDEFINED;
- Symbol *sym = addUndefinedTable(name, name, module, flags, nullptr, type);
+ Symbol *sym = addUndefinedTable(name, name, defaultModule, flags, nullptr, type);
sym->markLive();
sym->forceExport = config->exportTable;
return cast<TableSymbol>(sym);
@@ -724,8 +723,11 @@ TableSymbol *SymbolTable::resolveIndirectFunctionTable(bool required) {
}
if (config->importTable) {
- if (existing)
+ if (existing) {
+ existing->importModule = defaultModule;
+ existing->importName = functionTableName;
return cast<TableSymbol>(existing);
+ }
if (required)
return createUndefinedIndirectFunctionTable(functionTableName);
} else if ((existing && existing->isLive()) || config->exportTable ||
|
|
@llvm/pr-subscribers-lld-wasm Author: Sam Clegg (sbc100) ChangesWhen reference types are enabled clang will generate call_indirect instructions that explicitly reference the global In this case the resulting global symbol was not being correctly marked with explicit import name/module, resulting in the linker reporting errors when it was referenced. This issue was reported in WebAssembly/tool-conventions#158 Full diff: https://github.com/llvm/llvm-project/pull/97451.diff 3 Files Affected:
diff --git a/lld/test/wasm/import-table-explicit.s b/lld/test/wasm/import-table-explicit.s
new file mode 100644
index 0000000000000..1dc21beba0629
--- /dev/null
+++ b/lld/test/wasm/import-table-explicit.s
@@ -0,0 +1,26 @@
+# RUN: llvm-mc -mattr=+reference-types -filetype=obj -triple=wasm32-unknown-unknown %s -o %t.o
+# RUN: wasm-ld --import-table -o %t.wasm %t.o
+# RUN: obj2yaml %t.wasm | FileCheck %s
+
+.globl __indirect_function_table
+.tabletype __indirect_function_table, funcref
+
+.globl _start
+_start:
+ .functype _start () -> ()
+ i32.const 1
+ call_indirect __indirect_function_table, () -> ()
+ end_function
+
+# Verify the --import-table flag creates a table import
+
+# CHECK: - Type: IMPORT
+# CHECK-NEXT: Imports:
+# CHECK-NEXT: - Module: env
+# CHECK-NEXT: Field: __indirect_function_table
+# CHECK-NEXT: Kind: TABLE
+# CHECK-NEXT: Table:
+# CHECK-NEXT: Index: 0
+# CHECK-NEXT: ElemType: FUNCREF
+# CHECK-NEXT: Limits:
+# CHECK-NEXT: Minimum: 0x1
diff --git a/lld/test/wasm/import-table.test b/lld/test/wasm/import-table.s
similarity index 63%
rename from lld/test/wasm/import-table.test
rename to lld/test/wasm/import-table.s
index 73dc7189bbf28..7a0c94d130276 100644
--- a/lld/test/wasm/import-table.test
+++ b/lld/test/wasm/import-table.s
@@ -1,14 +1,14 @@
-# RUN: llvm-mc -filetype=obj -triple=wasm32-unknown-unknown %p/Inputs/start.s -o %t.start.o
# RUN: llvm-mc -filetype=obj -triple=wasm32-unknown-unknown %s -o %t.o
-# RUN: wasm-ld --export-all --import-table -o %t.wasm %t.start.o %t.o
+# RUN: wasm-ld --export-all --import-table -o %t.wasm %t.o
# RUN: obj2yaml %t.wasm | FileCheck %s
-.globl require_function_table
-require_function_table:
-.functype require_function_table () -> ()
- i32.const 1
- call_indirect () -> ()
- end_function
+.globl _start
+_start:
+ .functype _start () -> ()
+ i32.const 1
+ # call_indirect instruction implicitly references the function table
+ call_indirect () -> ()
+ end_function
# Verify the --import-table flag creates a table import
diff --git a/lld/wasm/SymbolTable.cpp b/lld/wasm/SymbolTable.cpp
index 00c347ea3ef24..09c463299b05c 100644
--- a/lld/wasm/SymbolTable.cpp
+++ b/lld/wasm/SymbolTable.cpp
@@ -681,10 +681,9 @@ TableSymbol *SymbolTable::createUndefinedIndirectFunctionTable(StringRef name) {
WasmTableType *type = make<WasmTableType>();
type->ElemType = ValType::FUNCREF;
type->Limits = limits;
- StringRef module(defaultModule);
uint32_t flags = config->exportTable ? 0 : WASM_SYMBOL_VISIBILITY_HIDDEN;
flags |= WASM_SYMBOL_UNDEFINED;
- Symbol *sym = addUndefinedTable(name, name, module, flags, nullptr, type);
+ Symbol *sym = addUndefinedTable(name, name, defaultModule, flags, nullptr, type);
sym->markLive();
sym->forceExport = config->exportTable;
return cast<TableSymbol>(sym);
@@ -724,8 +723,11 @@ TableSymbol *SymbolTable::resolveIndirectFunctionTable(bool required) {
}
if (config->importTable) {
- if (existing)
+ if (existing) {
+ existing->importModule = defaultModule;
+ existing->importName = functionTableName;
return cast<TableSymbol>(existing);
+ }
if (required)
return createUndefinedIndirectFunctionTable(functionTableName);
} else if ((existing && existing->isLive()) || config->exportTable ||
|
|
✅ With the latest revision this PR passed the C/C++ code formatter. |
…e types When reference types are enabled clang will generate call_indirect instructions that explicitly reference the global `__indirect_function_table` symbol. In this case the resulting global symbol was not being correctly marked with explicit import name/module, resulting in the linker reporting errors when it was referenced. This issue was reported in WebAssembly/tool-conventions#158
aheejin
reviewed
Jul 2, 2024
| @@ -724,8 +724,11 @@ TableSymbol *SymbolTable::resolveIndirectFunctionTable(bool required) { | |||
| } | |||
|
|
|||
| if (config->importTable) { | |||
| if (existing) | |||
| if (existing) { | |||
| existing->importModule = defaultModule; | |||
There was a problem hiding this comment.
Is it possible to import a table from a non-default module? If so, how do we do it?
There was a problem hiding this comment.
Also, before this PR, what was this importModule set to?
There was a problem hiding this comment.
This function only deal with one very particular table (__indirect_function_table). This table is implicitly generated by the linker and we don't support defining it explicitly anywhere. The import name is also fixed. It should not be possible to attach any kind of custom import name to it.
aheejin
approved these changes
Jul 2, 2024
lravenclaw
pushed a commit
to lravenclaw/llvm-project
that referenced
this pull request
Jul 3, 2024
…e types (llvm#97451) When reference types are enabled clang will generate call_indirect instructions that explicitly reference the global `__indirect_function_table` symbol. In this case the resulting global symbol was not being correctly marked with explicit import name/module, resulting in the linker reporting errors when it was referenced. This issue was reported in WebAssembly/tool-conventions#158
kbluck
pushed a commit
to kbluck/llvm-project
that referenced
this pull request
Jul 6, 2024
…e types (llvm#97451) When reference types are enabled clang will generate call_indirect instructions that explicitly reference the global `__indirect_function_table` symbol. In this case the resulting global symbol was not being correctly marked with explicit import name/module, resulting in the linker reporting errors when it was referenced. This issue was reported in WebAssembly/tool-conventions#158
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
When reference types are enabled clang will generate call_indirect instructions that explicitly reference the global
__indirect_function_tablesymbol.In this case the resulting global symbol was not being correctly marked with explicit import name/module, resulting in the linker reporting errors when it was referenced.
This issue was reported in WebAssembly/tool-conventions#158