[lld] e4f385d - [ELF] Support . and $ in symbol names in expressions
Fangrui Song via llvm-commits
llvm-commits at lists.llvm.org
Thu Mar 11 09:34:41 PST 2021
Author: Fangrui Song
Date: 2021-03-11T09:34:36-08:00
New Revision: e4f385d89448393b4d213339bbbbbbaa42b49489
URL: https://github.com/llvm/llvm-project/commit/e4f385d89448393b4d213339bbbbbbaa42b49489
DIFF: https://github.com/llvm/llvm-project/commit/e4f385d89448393b4d213339bbbbbbaa42b49489.diff
LOG: [ELF] Support . and $ in symbol names in expressions
GNU ld supports `.` and `$` in symbol names while LLD doesn't support them in
`readPrimary` expressions. Using `.` can result in such an error:
```
https://github.com/ClangBuiltLinux/linux/issues/1318
ld.lld: error: ./arch/powerpc/kernel/vmlinux.lds:255: malformed number: .TOC.
>>> __toc_ptr = (DEFINED (.TOC.) ? .TOC. : ADDR (.got)) + 0x8000;
```
Allow `.` (ppc64 special symbol `.TOC.`) and `$` (RISC-V special symbol `__global_pointer$`).
Change `diag[3-5].test` to use an invalid character `^`.
Note: GNU ld allows `~` in non-leading positions of a symbol name. `~`
is not used in practice, conflicts with the unary operator, and can
cause some parsing difficulty, so this patch does not add it.
Differential Revision: https://reviews.llvm.org/D98306
Added:
lld/test/ELF/linkerscript/symbol-name.test
Modified:
lld/ELF/ScriptParser.cpp
lld/test/ELF/linkerscript/diag3.test
lld/test/ELF/linkerscript/diag4.test
lld/test/ELF/linkerscript/diag5.test
Removed:
################################################################################
diff --git a/lld/ELF/ScriptParser.cpp b/lld/ELF/ScriptParser.cpp
index 4b15a71f029b..55093cc64bb9 100644
--- a/lld/ELF/ScriptParser.cpp
+++ b/lld/ELF/ScriptParser.cpp
@@ -1234,6 +1234,13 @@ static void checkIfExists(OutputSection *cmd, StringRef location) {
error(location + ": undefined section " + cmd->name);
}
+static bool isValidSymbolName(StringRef s) {
+ auto valid = [](char c) {
+ return isAlnum(c) || c == '$' || c == '.' || c == '_';
+ };
+ return !s.empty() && !isDigit(s[0]) && llvm::all_of(s, valid);
+}
+
Expr ScriptParser::readPrimary() {
if (peek() == "(")
return readParenExpr();
@@ -1408,7 +1415,7 @@ Expr ScriptParser::readPrimary() {
return [=] { return *val; };
// Tok is a symbol name.
- if (!isValidCIdentifier(tok))
+ if (!isValidSymbolName(tok))
setError("malformed number: " + tok);
script->referencedSymbols.push_back(tok);
return [=] { return script->getSymbolValue(tok, location); };
diff --git a/lld/test/ELF/linkerscript/diag3.test b/lld/test/ELF/linkerscript/diag3.test
index 8a0d552b1a89..1e4371241f30 100644
--- a/lld/test/ELF/linkerscript/diag3.test
+++ b/lld/test/ELF/linkerscript/diag3.test
@@ -5,9 +5,9 @@
SECTIONS {
.text : { *(.text) }
.keep : { *(.keep) }
- boom .temp : { *(.temp) }
+ boom ^temp : { *(.temp) }
}
-# CHECK: 8: malformed number: .temp
-# CHECK-NEXT: >>> boom .temp : { *(.temp) }
+# CHECK: 8: malformed number: ^temp
+# CHECK-NEXT: >>> boom ^temp : { *(.temp) }
# CHECK-NEXT: >>> ^
diff --git a/lld/test/ELF/linkerscript/diag4.test b/lld/test/ELF/linkerscript/diag4.test
index b04b6c6bd8ff..15d81fdc2be4 100644
--- a/lld/test/ELF/linkerscript/diag4.test
+++ b/lld/test/ELF/linkerscript/diag4.test
@@ -6,9 +6,9 @@
SECTIONS {
.text : { *(.text) }
.keep : { *(.keep) }
- boom .temp : { *(.temp) }
+ boom ^temp : { *(.temp) }
}
-# CHECK: 9: malformed number: .temp
-# CHECK-NEXT: >>> boom .temp : { *(.temp) }
-# CHECK-NEXT: >>> ^
\ No newline at end of file
+# CHECK: 9: malformed number: ^temp
+# CHECK-NEXT: >>> boom ^temp : { *(.temp) }
+# CHECK-NEXT: >>> ^
diff --git a/lld/test/ELF/linkerscript/diag5.test b/lld/test/ELF/linkerscript/diag5.test
index ebeee087d65e..15d81fdc2be4 100644
--- a/lld/test/ELF/linkerscript/diag5.test
+++ b/lld/test/ELF/linkerscript/diag5.test
@@ -6,9 +6,9 @@
SECTIONS {
.text : { *(.text) }
.keep : { *(.keep) }
- boom .temp : { *(.temp) }
+ boom ^temp : { *(.temp) }
}
-# CHECK: 9: malformed number: .temp
-# CHECK-NEXT: >>> boom .temp : { *(.temp) }
+# CHECK: 9: malformed number: ^temp
+# CHECK-NEXT: >>> boom ^temp : { *(.temp) }
# CHECK-NEXT: >>> ^
diff --git a/lld/test/ELF/linkerscript/symbol-name.test b/lld/test/ELF/linkerscript/symbol-name.test
new file mode 100644
index 000000000000..e9755add7950
--- /dev/null
+++ b/lld/test/ELF/linkerscript/symbol-name.test
@@ -0,0 +1,8 @@
+# REQUIRES: x86
+## Test that . and $ can be used by symbol names in expressions.
+
+# RUN: llvm-mc -filetype=obj -triple=x86_64 /dev/null -o %t.o
+# RUN: ld.lld -T %s %t.o -o /dev/null
+
+a0 = DEFINED(.TOC.) ? .TOC. : 0;
+a1 = DEFINED(__global_pointer$) ? __global_pointer$ : 0;
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