[lld] b99147b - [lld][WebAssembly] Don't defined indirect function table in relocatable output
Sam Clegg via llvm-commits
llvm-commits at lists.llvm.org
Tue Jan 19 13:10:58 PST 2021
Author: Sam Clegg
Date: 2021-01-19T12:59:20-08:00
New Revision: b99147b4fa7b361fba4eeefdb443dca72b8ee87f
URL: https://github.com/llvm/llvm-project/commit/b99147b4fa7b361fba4eeefdb443dca72b8ee87f
DIFF: https://github.com/llvm/llvm-project/commit/b99147b4fa7b361fba4eeefdb443dca72b8ee87f.diff
LOG: [lld][WebAssembly] Don't defined indirect function table in relocatable output
Object files (and the output --relocatable) should never define
__indirect_function_table. It should always be linker synthesized
with the final output executable.
Differential Revision: https://reviews.llvm.org/D94993
Added:
Modified:
lld/test/wasm/locals-duplicate.test
lld/test/wasm/relocatable.ll
lld/test/wasm/signature-mismatch.ll
lld/test/wasm/weak-alias.ll
lld/wasm/Driver.cpp
Removed:
################################################################################
diff --git a/lld/test/wasm/locals-duplicate.test b/lld/test/wasm/locals-duplicate.test
index cf9a148d4ab7..1d704ec2dff1 100644
--- a/lld/test/wasm/locals-duplicate.test
+++ b/lld/test/wasm/locals-duplicate.test
@@ -231,17 +231,19 @@
; RELOC-NEXT: ParamTypes: []
; RELOC-NEXT: ReturnTypes:
; RELOC-NEXT: - I32
+; RELOC-NEXT: - Type: IMPORT
+; RELOC-NEXT: Imports:
+; RELOC-NEXT: - Module: env
+; RELOC-NEXT: Field: __indirect_function_table
+; RELOC-NEXT: Kind: TABLE
+; RELOC-NEXT: Table:
+; RELOC-NEXT: Index: 0
+; RELOC-NEXT: ElemType: FUNCREF
+; RELOC-NEXT: Limits:
+; RELOC-NEXT: Initial: 0x3
; RELOC-NEXT: - Type: FUNCTION
; RELOC-NEXT: FunctionTypes: [ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
; RELOC-NEXT: 0, 0 ]
-; RELOC-NEXT: - Type: TABLE
-; RELOC-NEXT: Tables:
-; RELOC-NEXT: - Index: 0
-; RELOC-NEXT: ElemType: FUNCREF
-; RELOC-NEXT: Limits:
-; RELOC-NEXT: Flags: [ HAS_MAX ]
-; RELOC-NEXT: Initial: 0x7
-; RELOC-NEXT: Maximum: 0x7
; RELOC-NEXT: - Type: MEMORY
; RELOC-NEXT: Memories:
; RELOC-NEXT: - Initial: 0x1
@@ -412,7 +414,7 @@
; RELOC-NEXT: - Index: 8
; RELOC-NEXT: Kind: TABLE
; RELOC-NEXT: Name: __indirect_function_table
-; RELOC-NEXT: Flags: [ VISIBILITY_HIDDEN ]
+; RELOC-NEXT: Flags: [ UNDEFINED, NO_STRIP ]
; RELOC-NEXT: Table: 0
; RELOC-NEXT: - Index: 9
; RELOC-NEXT: Kind: FUNCTION
diff --git a/lld/test/wasm/relocatable.ll b/lld/test/wasm/relocatable.ll
index e8129da9ad3d..7de51a38f5c9 100644
--- a/lld/test/wasm/relocatable.ll
+++ b/lld/test/wasm/relocatable.ll
@@ -1,7 +1,10 @@
; RUN: llvm-mc -filetype=obj -triple=wasm32-unknown-unknown %p/Inputs/hello.s -o %t.hello.o
; RUN: llc -filetype=obj %s -o %t.o
-; RUN: wasm-ld -r -o %t.wasm %t.hello.o %t.o
-; RUN: obj2yaml %t.wasm | FileCheck %s
+; RUN: wasm-ld -r -o %t2.o %t.hello.o %t.o
+; RUN: obj2yaml %t2.o | FileCheck %s
+
+; Verify the resulting object can be used as linker input
+; RUN: wasm-ld --allow-undefined -o %t.wasm %t2.o --export-table
target triple = "wasm32-unknown-unknown"
@@ -32,6 +35,11 @@ entry:
; Test that __attribute__(used) (i.e NO_STRIP) is preserved in the relocated symbol table
@llvm.used = appending global [1 x i8*] [i8* bitcast (i32 ()* @my_func to i8*)], section "llvm.metadata"
+define void @_start() {
+ ret void
+}
+
+
; CHECK: --- !WASM
; CHECK-NEXT: FileHeader:
; CHECK-NEXT: Version: 0x1
@@ -63,16 +71,16 @@ entry:
; CHECK-NEXT: Field: bar_import
; CHECK-NEXT: Kind: FUNCTION
; CHECK-NEXT: SigIndex: 1
+; 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: Initial: 0x3
; CHECK-NEXT: - Type: FUNCTION
-; CHECK-NEXT: FunctionTypes: [ 2, 1, 1 ]
-; CHECK-NEXT: - Type: TABLE
-; CHECK-NEXT: Tables:
-; CHECK-NEXT: - Index: 0
-; CHECK-NEXT: ElemType: FUNCREF
-; CHECK-NEXT: Limits:
-; CHECK-NEXT: Flags: [ HAS_MAX ]
-; CHECK-NEXT: Initial: 0x4
-; CHECK-NEXT: Maximum: 0x4
+; CHECK-NEXT: FunctionTypes: [ 2, 1, 1, 2 ]
; CHECK-NEXT: - Type: MEMORY
; CHECK-NEXT: Memories:
; CHECK-NEXT: - Initial: 0x1
diff --git a/lld/test/wasm/signature-mismatch.ll b/lld/test/wasm/signature-mismatch.ll
index 65ce73910ffa..931ec9ef1234 100644
--- a/lld/test/wasm/signature-mismatch.ll
+++ b/lld/test/wasm/signature-mismatch.ll
@@ -82,7 +82,7 @@ declare i32 @ret32(i32, i64, i32) local_unnamed_addr
; RELOC-NEXT: - Index: 3
; RELOC-NEXT: Kind: TABLE
; RELOC-NEXT: Name: __indirect_function_table
-; RELOC-NEXT: Flags: [ VISIBILITY_HIDDEN ]
+; RELOC-NEXT: Flags: [ UNDEFINED, NO_STRIP ]
; RELOC-NEXT: Table: 0
; RELOC-NEXT: - Index: 4
; RELOC-NEXT: Kind: FUNCTION
diff --git a/lld/test/wasm/weak-alias.ll b/lld/test/wasm/weak-alias.ll
index 387501963d4b..90531fa135ff 100644
--- a/lld/test/wasm/weak-alias.ll
+++ b/lld/test/wasm/weak-alias.ll
@@ -149,16 +149,16 @@ entry:
; RELOC-NEXT: Kind: GLOBAL
; RELOC-NEXT: GlobalType: I32
; RELOC-NEXT: GlobalMutable: true
+; RELOC-NEXT: - Module: env
+; RELOC-NEXT: Field: __indirect_function_table
+; RELOC-NEXT: Kind: TABLE
+; RELOC-NEXT: Table:
+; RELOC-NEXT: Index: 0
+; RELOC-NEXT: ElemType: FUNCREF
+; RELOC-NEXT: Limits:
+; RELOC-NEXT: Initial: 0x1
; RELOC-NEXT: - Type: FUNCTION
; RELOC-NEXT: FunctionTypes: [ 0, 1, 1, 1, 1, 1 ]
-; RELOC-NEXT: - Type: TABLE
-; RELOC-NEXT: Tables:
-; RELOC-NEXT: - Index: 0
-; RELOC-NEXT: ElemType: FUNCREF
-; RELOC-NEXT: Limits:
-; RELOC-NEXT: Flags: [ HAS_MAX ]
-; RELOC-NEXT: Initial: 0x2
-; RELOC-NEXT: Maximum: 0x2
; RELOC-NEXT: - Type: MEMORY
; RELOC-NEXT: Memories:
; RELOC-NEXT: - Initial: 0x0
@@ -279,7 +279,7 @@ entry:
; RELOC-NEXT: - Index: 8
; RELOC-NEXT: Kind: TABLE
; RELOC-NEXT: Name: __indirect_function_table
-; RELOC-NEXT: Flags: [ VISIBILITY_HIDDEN ]
+; RELOC-NEXT: Flags: [ UNDEFINED, NO_STRIP ]
; RELOC-NEXT: Table: 0
; RELOC-NEXT: - Type: CUSTOM
; RELOC-NEXT: Name: name
diff --git a/lld/wasm/Driver.cpp b/lld/wasm/Driver.cpp
index b988f9fa7fd1..830e4bf1744f 100644
--- a/lld/wasm/Driver.cpp
+++ b/lld/wasm/Driver.cpp
@@ -817,22 +817,31 @@ static TableSymbol *createUndefinedIndirectFunctionTable(StringRef name) {
}
static TableSymbol *resolveIndirectFunctionTable() {
- // Even though we may not need a table, if the user explicitly specified
- // --import-table or --export-table, ensure a table is residualized.
- if (config->importTable)
- return createUndefinedIndirectFunctionTable(functionTableName);
- if (config->exportTable)
- return createDefinedIndirectFunctionTable(functionTableName);
-
- // Otherwise, check to the symtab to find the indirect function table.
- if (Symbol *sym = symtab->find(functionTableName)) {
- if (sym->isLive()) {
- if (auto *t = dyn_cast<TableSymbol>(sym)) {
- return t->isDefined()
- ? t
- : createDefinedIndirectFunctionTable(functionTableName);
- }
+ Symbol *existingTable = symtab->find(functionTableName);
+ if (existingTable) {
+ if (!isa<TableSymbol>(existingTable)) {
+ error(Twine("reserved symbol must be of type table: `") +
+ functionTableName + "`");
+ return nullptr;
}
+ if (existingTable->isDefined()) {
+ error(Twine("reserved symbol must not be defined in input files: `") +
+ functionTableName + "`");
+ return nullptr;
+ }
+ }
+
+ if (config->importTable) {
+ if (existingTable)
+ return cast<TableSymbol>(existingTable);
+ else
+ return createUndefinedIndirectFunctionTable(functionTableName);
+ } else if ((existingTable && existingTable->isLive()) ||
+ config->exportTable) {
+ // A defined table is required. Either because the user request an exported
+ // table or because the table symbol is already live. The existing table is
+ // guaranteed to be undefined due to the check above.
+ return createDefinedIndirectFunctionTable(functionTableName);
}
// An indirect function table will only be present in the symbol table if
@@ -1029,11 +1038,13 @@ void LinkerDriver::linkerMain(ArrayRef<const char *> argsArr) {
// Do size optimizations: garbage collection
markLive();
- // Provide the indirect funciton table if needed.
- WasmSym::indirectFunctionTable = resolveIndirectFunctionTable();
+ if (!config->relocatable) {
+ // Provide the indirect funciton table if needed.
+ WasmSym::indirectFunctionTable = resolveIndirectFunctionTable();
- if (errorCount())
- return;
+ if (errorCount())
+ return;
+ }
// Write the result to the file.
writeResult();
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