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[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
This commit is contained in:
Sam Clegg 2021-01-19 12:10:15 -08:00
parent da986511fb
commit b99147b4fa
5 changed files with 70 additions and 49 deletions
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20
lld/test/wasm/locals-duplicate.test
View File

@ -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

30
lld/test/wasm/relocatable.ll
View File

@ -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

2
lld/test/wasm/signature-mismatch.ll
View File

@ -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

18
lld/test/wasm/weak-alias.ll
View File

@ -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

49
lld/wasm/Driver.cpp
View File

@ -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();