[lld] 34d033c - [lld][WebAssembly] Allow --export of optional start/stop symbols
Sam Clegg via llvm-commits
llvm-commits at lists.llvm.org
Tue Feb 9 13:15:07 PST 2021
Author: Sam Clegg
Date: 2021-02-09T13:14:52-08:00
New Revision: 34d033ca129fdb1507427d45f518fdb523847732
URL: https://github.com/llvm/llvm-project/commit/34d033ca129fdb1507427d45f518fdb523847732
DIFF: https://github.com/llvm/llvm-project/commit/34d033ca129fdb1507427d45f518fdb523847732.diff
LOG: [lld][WebAssembly] Allow --export of optional start/stop symbols
This moves the error checking until after all optional
symbols (including the section start/end symbols) have
been created.
Differential Revision: https://reviews.llvm.org/D96318
Added:
lld/test/wasm/export-optional.s
Modified:
lld/wasm/Driver.cpp
lld/wasm/Writer.cpp
Removed:
################################################################################
diff --git a/lld/test/wasm/export-optional.s b/lld/test/wasm/export-optional.s
new file mode 100644
index 000000000000..7e6f4debc0a9
--- /dev/null
+++ b/lld/test/wasm/export-optional.s
@@ -0,0 +1,31 @@
+# Test the --export of optional linker-synthetic symbols works.
+# Specifically the __start_xxx and __end_xx symbols.
+
+# RUN: llvm-mc -filetype=obj -triple=wasm32-unknown-unknown %s -o %t.o
+# RUN: wasm-ld --export=__start_foo %t.o -o %t.wasm
+# RUN: obj2yaml %t.wasm | FileCheck %s
+
+ .globl _start
+_start:
+ .functype _start () -> ()
+ i32.load foo
+ drop
+ end_function
+
+ .globl foo
+ .section foo,"",@
+foo:
+ .int32 42
+ .size foo, 4
+
+# CHECK: - Type: EXPORT
+# CHECK-NEXT: Exports:
+# CHECK-NEXT: - Name: memory
+# CHECK-NEXT: Kind: MEMORY
+# CHECK-NEXT: Index: 0
+# CHECK-NEXT: - Name: _start
+# CHECK-NEXT: Kind: FUNCTION
+# CHECK-NEXT: Index: 0
+# CHECK-NEXT: - Name: __start_foo
+# CHECK-NEXT: Kind: GLOBAL
+# CHECK-NEXT: Index: 1
diff --git a/lld/wasm/Driver.cpp b/lld/wasm/Driver.cpp
index 5927d1b53e7d..4cd529686e4d 100644
--- a/lld/wasm/Driver.cpp
+++ b/lld/wasm/Driver.cpp
@@ -1015,11 +1015,6 @@ void LinkerDriver::linkerMain(ArrayRef<const char *> argsArr) {
Symbol *sym = symtab->find(arg->getValue());
if (sym && sym->isDefined())
sym->forceExport = true;
- else if (config->unresolvedSymbols == UnresolvedPolicy::ReportError)
- error(Twine("symbol exported via --export not found: ") +
- arg->getValue());
- else if (config->unresolvedSymbols == UnresolvedPolicy::Warn)
- warn(Twine("symbol exported via --export not found: ") + arg->getValue());
}
if (!config->relocatable && !config->isPic) {
diff --git a/lld/wasm/Writer.cpp b/lld/wasm/Writer.cpp
index 1587e97b5b2d..aeafc330e103 100644
--- a/lld/wasm/Writer.cpp
+++ b/lld/wasm/Writer.cpp
@@ -1350,6 +1350,19 @@ void Writer::run() {
addStartStopSymbols(seg);
}
+ // Delay reporting error about explict exports until after addStartStopSymbols
+ // which can create optional symbols.
+ for (auto &entry : config->exportedSymbols) {
+ StringRef name = entry.first();
+ Symbol *sym = symtab->find(name);
+ if (sym && sym->isDefined())
+ sym->forceExport = true;
+ else if (config->unresolvedSymbols == UnresolvedPolicy::ReportError)
+ error(Twine("symbol exported via --export not found: ") + name);
+ else if (config->unresolvedSymbols == UnresolvedPolicy::Warn)
+ warn(Twine("symbol exported via --export not found: ") + name);
+ }
+
log("-- scanRelocations");
scanRelocations();
log("-- finalizeIndirectFunctionTable");
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