Add memory ORIGIN and LENGTH expression support

Adds support for the ORIGIN and LENGTH linker script built in functions.

  ORIGIN(memory) Return the origin of the memory region
  LENGTH(memory) Return the length of the memory region

Redo of D29775 for refactored linker script parsing.

Patch by Robert Clarke

Differential Revision: https://reviews.llvm.org/D32934

llvm-svn: 302564

2 files changed, 45 insertions, 0 deletions

diff --git a/lld/ELF/ScriptParser.cpp b/lld/ELF/ScriptParser.cpp
index 032ecd50f3e..ca4f4cd2773 100644
--- a/lld/ELF/ScriptParser.cpp
+++ b/lld/ELF/ScriptParser.cpp
@@ -900,10 +900,22 @@ Expr ScriptParser::readPrimary() {
     StringRef Name = readParenLiteral();
     return [=] { return Script->isDefined(Name) ? 1 : 0; };
   }
+  if (Tok == "LENGTH") {
+    StringRef Name = readParenLiteral();
+    if (Script->Opt.MemoryRegions.count(Name) == 0)
+      setError("memory region not defined: " + Name);
+    return [=] { return Script->Opt.MemoryRegions[Name].Length; };
+  }
   if (Tok == "LOADADDR") {
     StringRef Name = readParenLiteral();
     return [=] { return Script->getOutputSection(Location, Name)->getLMA(); };
   }
+  if (Tok == "ORIGIN") {
+    StringRef Name = readParenLiteral();
+    if (Script->Opt.MemoryRegions.count(Name) == 0)
+      setError("memory region not defined: " + Name);
+    return [=] { return Script->Opt.MemoryRegions[Name].Origin; };
+  }
   if (Tok == "SEGMENT_START") {
     expect("(");
     skip();
diff --git a/lld/test/ELF/linkerscript/symbol-memoryexpr.s b/lld/test/ELF/linkerscript/symbol-memoryexpr.s
new file mode 100644
index 00000000000..9c75274e164
--- /dev/null
+++ b/lld/test/ELF/linkerscript/symbol-memoryexpr.s
@@ -0,0 +1,33 @@
+# REQUIRES: x86
+# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t
+
+# RUN: echo "MEMORY { \
+# RUN:   ram (rwx)  : ORIGIN = 0x8000, LENGTH = 256K \
+# RUN: } \
+# RUN: SECTIONS { \
+# RUN:         origin = ORIGIN(ram); \
+# RUN:         length = LENGTH(ram); \
+# RUN:         end    = ORIGIN(ram) + LENGTH(ram); \
+# 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: 0000000000008000 .text 00000000 _start
+# CHECK-NEXT: 0000000000008000 *ABS* 00000000 origin
+# CHECK-NEXT: 0000000000040000 *ABS* 00000000 length
+# CHECK-NEXT: 0000000000048000 *ABS* 00000000 end
+
+# RUN: echo "SECTIONS { \
+# RUN:         no_exist_origin = ORIGIN(ram); \
+# RUN:         no_exist_length = LENGTH(ram); \
+# RUN:       }" > %t2.script
+# RUN: not ld.lld -o %t2 --script %t2.script %t 2>&1 \
+# RUN:  | FileCheck -check-prefix=ERR %s
+# ERR: {{.*}}.script:1: memory region not defined: ram
+
+
+.global _start
+_start:
+ nop