From 91b95b61f8b815e45ad6c3cdb1d35c70bb9e7bff Mon Sep 17 00:00:00 2001
From: Rui Ueyama <ruiu@google.com>
Date: Tue, 9 May 2017 18:24:38 +0000
Subject: [PATCH] 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
---
 lld/ELF/ScriptParser.cpp                      | 12 ++++++++++
 lld/test/ELF/linkerscript/symbol-memoryexpr.s | 33 +++++++++++++++++++++++++++
 2 files changed, 45 insertions(+)
 create mode 100644 lld/test/ELF/linkerscript/symbol-memoryexpr.s

diff --git a/lld/ELF/ScriptParser.cpp b/lld/ELF/ScriptParser.cpp
index 032ecd5..ca4f4cd 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 0000000..9c75274
--- /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
-- 
2.7.4