[ELF] Linkerscript: symbol assignments with indentifiers on the right side of expression.
In symbol assignments symbol may appear on the right-hand side of the expression:
(https://svnweb.freebsd.org/base/head/sys/conf/ldscript.amd64?revision=284870&view=markup#l8)
kernphys = CONSTANT (MAXPAGESIZE);
. = kernbase + kernphys + SIZEOF_HEADERS;
Patch implements that.
Differential revision: https://reviews.llvm.org/D22759
llvm-svn: 276784
diff --git a/lld/ELF/LinkerScript.cpp b/lld/ELF/LinkerScript.cpp
index 3889f10..1079a2f 100644
--- a/lld/ELF/LinkerScript.cpp
+++ b/lld/ELF/LinkerScript.cpp
@@ -756,6 +756,29 @@
// script expression.
Expr ScriptParser::readExpr() { return readExpr1(readPrimary(), 0); }
+static uint64_t getSymbolValue(StringRef S) {
+ switch (Config->EKind) {
+ case ELF32LEKind:
+ if (SymbolBody *B = Symtab<ELF32LE>::X->find(S))
+ return B->getVA<ELF32LE>();
+ break;
+ case ELF32BEKind:
+ if (SymbolBody *B = Symtab<ELF32BE>::X->find(S))
+ return B->getVA<ELF32BE>();
+ break;
+ case ELF64LEKind:
+ if (SymbolBody *B = Symtab<ELF64LE>::X->find(S))
+ return B->getVA<ELF64LE>();
+ break;
+ case ELF64BEKind:
+ if (SymbolBody *B = Symtab<ELF64BE>::X->find(S))
+ return B->getVA<ELF64BE>();
+ break;
+ }
+ error("symbol not found: " + S);
+ return 0;
+}
+
// This is a part of the operator-precedence parser. This function
// assumes that the remaining token stream starts with an operator.
Expr ScriptParser::readExpr1(Expr Lhs, int MinPrec) {
@@ -844,10 +867,13 @@
return [](uint64_t Dot) { return alignTo(Dot, Target->PageSize); };
}
- // Parse a number literal
+ // Parse a symbol name or a number literal.
uint64_t V = 0;
- if (Tok.getAsInteger(0, V))
- setError("malformed number: " + Tok);
+ if (Tok.getAsInteger(0, V)) {
+ if (!isValidCIdentifier(Tok))
+ setError("malformed number: " + Tok);
+ return [=](uint64_t Dot) { return getSymbolValue(Tok); };
+ }
return [=](uint64_t Dot) { return V; };
}
diff --git a/lld/test/ELF/linkerscript/linkerscript-symbol-assignexpr.s b/lld/test/ELF/linkerscript/linkerscript-symbol-assignexpr.s
new file mode 100644
index 0000000..353800b
--- /dev/null
+++ b/lld/test/ELF/linkerscript/linkerscript-symbol-assignexpr.s
@@ -0,0 +1,32 @@
+# REQUIRES: x86
+# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t
+
+# RUN: echo "SECTIONS { \
+# RUN: symbol = CONSTANT(MAXPAGESIZE); \
+# RUN: symbol2 = symbol + 0x1234; \
+# RUN: symbol3 = symbol2; \
+# RUN: }" > %t.script
+# RUN: ld.lld -o %t1 --script %t.script %t
+# RUN: llvm-objdump -t %t1 | FileCheck %s
+
+# CHECK: SYMBOL TABLE:
+# CHECK-NEXT: 0000000000000000 *UND* 00000000
+# CHECK-NEXT: 0000000000000120 .text 00000000 _start
+# CHECK-NEXT: 0000000000000121 .text 00000000 foo
+# CHECK-NEXT: 0000000000001000 *ABS* 00000000 symbol
+# CHECK-NEXT: 0000000000002234 *ABS* 00000000 symbol2
+# CHECK-NEXT: 0000000000002234 *ABS* 00000000 symbol3
+
+# RUN: echo "SECTIONS { \
+# RUN: symbol2 = symbol; \
+# RUN: }" > %t2.script
+# RUN: not ld.lld -o %t2 --script %t2.script %t 2>&1 \
+# RUN: | FileCheck -check-prefix=ERR %s
+# ERR: symbol not found: symbol
+
+.global _start
+_start:
+ nop
+
+.global foo
+foo: