[llvm] r323165 - [WebAssembly] Store function index rather than table index in TABLE_INDEX relocations
Sam Clegg via llvm-commits
llvm-commits at lists.llvm.org
Mon Jan 22 17:23:17 PST 2018
Author: sbc
Date: Mon Jan 22 17:23:17 2018
New Revision: 323165
URL: http://llvm.org/viewvc/llvm-project?rev=323165&view=rev
Log:
[WebAssembly] Store function index rather than table index in TABLE_INDEX relocations
Relocations of type R_WEBASSEMBLY_TABLE_INDEX represent places
where the table index for a given function is needed. While the
value stored in this location is a table index, the index in
the relocation entry itself is a function index (the index of
the function which is to be called indirectly).
This is how is was spec'd originally but the LLVM implementation
didn't do this. This makes things a little simpler in the linker
since the table in the input file can essentially be ignored that
the output table can be created purely based on these relocations.
Patch by Nicholas Wilson!
Differential Revision: https://reviews.llvm.org/D42080
Modified:
llvm/trunk/lib/MC/WasmObjectWriter.cpp
llvm/trunk/test/MC/WebAssembly/external-func-address.ll
llvm/trunk/test/MC/WebAssembly/func-address.ll
llvm/trunk/test/MC/WebAssembly/global-ctor-dtor.ll
llvm/trunk/test/MC/WebAssembly/weak-alias.ll
Modified: llvm/trunk/lib/MC/WasmObjectWriter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/WasmObjectWriter.cpp?rev=323165&r1=323164&r2=323165&view=diff
==============================================================================
--- llvm/trunk/lib/MC/WasmObjectWriter.cpp (original)
+++ llvm/trunk/lib/MC/WasmObjectWriter.cpp Mon Jan 22 17:23:17 2018
@@ -499,25 +499,44 @@ static const MCSymbolWasm* ResolveSymbol
}
// Compute a value to write into the code at the location covered
-// by RelEntry. This value isn't used by the static linker, since
-// we have addends; it just serves to make the code more readable
-// and to make standalone wasm modules directly usable.
+// by RelEntry. This value isn't used by the static linker; it just serves
+// to make the object format more readable and more likely to be directly
+// useable.
uint32_t
WasmObjectWriter::getProvisionalValue(const WasmRelocationEntry &RelEntry) {
- const MCSymbolWasm *Sym = ResolveSymbol(*RelEntry.Symbol);
- // For undefined symbols, use zero
- if (!Sym->isDefined())
- return 0;
-
- uint32_t GlobalIndex = SymbolIndices[Sym];
- const WasmGlobal& Global = Globals[GlobalIndex - NumGlobalImports];
- uint64_t Address = Global.InitialValue + RelEntry.Addend;
-
- // Ignore overflow. LLVM allows address arithmetic to silently wrap.
- uint32_t Value = Address;
+ switch (RelEntry.Type) {
+ case wasm::R_WEBASSEMBLY_TABLE_INDEX_SLEB:
+ case wasm::R_WEBASSEMBLY_TABLE_INDEX_I32:
+ // Provitional value is the indirect symbol index
+ if (!IndirectSymbolIndices.count(RelEntry.Symbol))
+ report_fatal_error("symbol not found in table index space: " +
+ RelEntry.Symbol->getName());
+ return IndirectSymbolIndices[RelEntry.Symbol];
+ case wasm::R_WEBASSEMBLY_FUNCTION_INDEX_LEB:
+ case wasm::R_WEBASSEMBLY_TYPE_INDEX_LEB:
+ case wasm::R_WEBASSEMBLY_GLOBAL_INDEX_LEB:
+ // Provitional value is function/type/global index itself
+ return getRelocationIndexValue(RelEntry);
+ case wasm::R_WEBASSEMBLY_MEMORY_ADDR_LEB:
+ case wasm::R_WEBASSEMBLY_MEMORY_ADDR_I32:
+ case wasm::R_WEBASSEMBLY_MEMORY_ADDR_SLEB: {
+ // Provitional value is address of the global
+ const MCSymbolWasm *Sym = ResolveSymbol(*RelEntry.Symbol);
+ // For undefined symbols, use zero
+ if (!Sym->isDefined())
+ return 0;
+
+ uint32_t GlobalIndex = SymbolIndices[Sym];
+ const WasmGlobal& Global = Globals[GlobalIndex - NumGlobalImports];
+ uint64_t Address = Global.InitialValue + RelEntry.Addend;
- return Value;
+ // Ignore overflow. LLVM allows address arithmetic to silently wrap.
+ return Address;
+ }
+ default:
+ llvm_unreachable("invalid relocation type");
+ }
}
static void addData(SmallVectorImpl<char> &DataBytes,
@@ -564,32 +583,19 @@ static void addData(SmallVectorImpl<char
DEBUG(dbgs() << "addData -> " << DataBytes.size() << "\n");
}
-uint32_t WasmObjectWriter::getRelocationIndexValue(
- const WasmRelocationEntry &RelEntry) {
- switch (RelEntry.Type) {
- case wasm::R_WEBASSEMBLY_TABLE_INDEX_SLEB:
- case wasm::R_WEBASSEMBLY_TABLE_INDEX_I32:
- if (!IndirectSymbolIndices.count(RelEntry.Symbol))
- report_fatal_error("symbol not found in table index space: " +
- RelEntry.Symbol->getName());
- return IndirectSymbolIndices[RelEntry.Symbol];
- case wasm::R_WEBASSEMBLY_FUNCTION_INDEX_LEB:
- case wasm::R_WEBASSEMBLY_GLOBAL_INDEX_LEB:
- case wasm::R_WEBASSEMBLY_MEMORY_ADDR_LEB:
- case wasm::R_WEBASSEMBLY_MEMORY_ADDR_SLEB:
- case wasm::R_WEBASSEMBLY_MEMORY_ADDR_I32:
- if (!SymbolIndices.count(RelEntry.Symbol))
- report_fatal_error("symbol not found in function/global index space: " +
- RelEntry.Symbol->getName());
- return SymbolIndices[RelEntry.Symbol];
- case wasm::R_WEBASSEMBLY_TYPE_INDEX_LEB:
+uint32_t
+WasmObjectWriter::getRelocationIndexValue(const WasmRelocationEntry &RelEntry) {
+ if (RelEntry.Type == wasm::R_WEBASSEMBLY_TYPE_INDEX_LEB) {
if (!TypeIndices.count(RelEntry.Symbol))
report_fatal_error("symbol not found in type index space: " +
RelEntry.Symbol->getName());
return TypeIndices[RelEntry.Symbol];
- default:
- llvm_unreachable("invalid relocation type");
}
+
+ if (!SymbolIndices.count(RelEntry.Symbol))
+ report_fatal_error("symbol not found in function/global index space: " +
+ RelEntry.Symbol->getName());
+ return SymbolIndices[RelEntry.Symbol];
}
// Apply the portions of the relocation records that we can handle ourselves
@@ -603,35 +609,23 @@ void WasmObjectWriter::applyRelocations(
RelEntry.Offset;
DEBUG(dbgs() << "applyRelocation: " << RelEntry << "\n");
+ uint32_t Value = getProvisionalValue(RelEntry);
+
switch (RelEntry.Type) {
- case wasm::R_WEBASSEMBLY_TABLE_INDEX_SLEB:
case wasm::R_WEBASSEMBLY_FUNCTION_INDEX_LEB:
case wasm::R_WEBASSEMBLY_TYPE_INDEX_LEB:
- case wasm::R_WEBASSEMBLY_GLOBAL_INDEX_LEB: {
- uint32_t Index = getRelocationIndexValue(RelEntry);
- WritePatchableSLEB(Stream, Index, Offset);
- break;
- }
- case wasm::R_WEBASSEMBLY_TABLE_INDEX_I32: {
- uint32_t Index = getRelocationIndexValue(RelEntry);
- WriteI32(Stream, Index, Offset);
- break;
- }
- case wasm::R_WEBASSEMBLY_MEMORY_ADDR_SLEB: {
- uint32_t Value = getProvisionalValue(RelEntry);
- WritePatchableSLEB(Stream, Value, Offset);
- break;
- }
- case wasm::R_WEBASSEMBLY_MEMORY_ADDR_LEB: {
- uint32_t Value = getProvisionalValue(RelEntry);
+ case wasm::R_WEBASSEMBLY_GLOBAL_INDEX_LEB:
+ case wasm::R_WEBASSEMBLY_MEMORY_ADDR_LEB:
WritePatchableLEB(Stream, Value, Offset);
break;
- }
- case wasm::R_WEBASSEMBLY_MEMORY_ADDR_I32: {
- uint32_t Value = getProvisionalValue(RelEntry);
+ case wasm::R_WEBASSEMBLY_TABLE_INDEX_I32:
+ case wasm::R_WEBASSEMBLY_MEMORY_ADDR_I32:
WriteI32(Stream, Value, Offset);
break;
- }
+ case wasm::R_WEBASSEMBLY_TABLE_INDEX_SLEB:
+ case wasm::R_WEBASSEMBLY_MEMORY_ADDR_SLEB:
+ WritePatchableSLEB(Stream, Value, Offset);
+ break;
default:
llvm_unreachable("invalid relocation type");
}
Modified: llvm/trunk/test/MC/WebAssembly/external-func-address.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/WebAssembly/external-func-address.ll?rev=323165&r1=323164&r2=323165&view=diff
==============================================================================
--- llvm/trunk/test/MC/WebAssembly/external-func-address.ll (original)
+++ llvm/trunk/test/MC/WebAssembly/external-func-address.ll Mon Jan 22 17:23:17 2018
@@ -34,5 +34,5 @@ declare void @f1(i32) #1
; CHECK: - Type: DATA
; CHECK-NEXT: Relocations:
; CHECK-NEXT: - Type: R_WEBASSEMBLY_TABLE_INDEX_I32
-; CHECK-NEXT: Index: 1
+; CHECK-NEXT: Index: 0
; CHECK-NEXT: Offset: 0x00000006
Modified: llvm/trunk/test/MC/WebAssembly/func-address.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/WebAssembly/func-address.ll?rev=323165&r1=323164&r2=323165&view=diff
==============================================================================
--- llvm/trunk/test/MC/WebAssembly/func-address.ll (original)
+++ llvm/trunk/test/MC/WebAssembly/func-address.ll Mon Jan 22 17:23:17 2018
@@ -42,6 +42,6 @@ entry:
; CHECK: Relocation {
; CHECK: Type: R_WEBASSEMBLY_TABLE_INDEX_SLEB (1)
; CHECK: Offset: 0x1E
-; CHECK: Index: 0x1
+; CHECK: Index: 0x2
; CHECK: }
; CHECK: }
Modified: llvm/trunk/test/MC/WebAssembly/global-ctor-dtor.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/WebAssembly/global-ctor-dtor.ll?rev=323165&r1=323164&r2=323165&view=diff
==============================================================================
--- llvm/trunk/test/MC/WebAssembly/global-ctor-dtor.ll (original)
+++ llvm/trunk/test/MC/WebAssembly/global-ctor-dtor.ll Mon Jan 22 17:23:17 2018
@@ -95,7 +95,7 @@ declare void @func3()
; CHECK-NEXT: Index: 0
; CHECK-NEXT: Offset: 0x00000004
; CHECK-NEXT: - Type: R_WEBASSEMBLY_TABLE_INDEX_SLEB
-; CHECK-NEXT: Index: 1
+; CHECK-NEXT: Index: 5
; CHECK-NEXT: Offset: 0x0000000F
; CHECK-NEXT: - Type: R_WEBASSEMBLY_MEMORY_ADDR_SLEB
; CHECK-NEXT: Index: 0
@@ -107,7 +107,7 @@ declare void @func3()
; CHECK-NEXT: Index: 2
; CHECK-NEXT: Offset: 0x0000002C
; CHECK-NEXT: - Type: R_WEBASSEMBLY_TABLE_INDEX_SLEB
-; CHECK-NEXT: Index: 2
+; CHECK-NEXT: Index: 7
; CHECK-NEXT: Offset: 0x00000037
; CHECK-NEXT: - Type: R_WEBASSEMBLY_MEMORY_ADDR_SLEB
; CHECK-NEXT: Index: 0
Modified: llvm/trunk/test/MC/WebAssembly/weak-alias.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/WebAssembly/weak-alias.ll?rev=323165&r1=323164&r2=323165&view=diff
==============================================================================
--- llvm/trunk/test/MC/WebAssembly/weak-alias.ll (original)
+++ llvm/trunk/test/MC/WebAssembly/weak-alias.ll Mon Jan 22 17:23:17 2018
@@ -174,7 +174,7 @@ entry:
; CHECK-NEXT: Index: 1
; CHECK-NEXT: Offset: 0x0000000F
; CHECK-NEXT: - Type: R_WEBASSEMBLY_TABLE_INDEX_I32
-; CHECK-NEXT: Index: 2
+; CHECK-NEXT: Index: 0
; CHECK-NEXT: Offset: 0x00000018
; CHECK-NEXT: Segments:
; CHECK-NEXT: - SectionOffset: 6
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