[PATCH] D24898: [ELF] Support -z common-page-size option

[Petr Hosek via llvm-commits]

phosek updated this revision to Diff 72407.

https://reviews.llvm.org/D24898

Files:
  ELF/Config.h
  ELF/Driver.cpp
  ELF/LinkerScript.cpp
  test/ELF/linkerscript/zcommon-page-size.s

Index: test/ELF/linkerscript/zcommon-page-size.s
===================================================================
--- /dev/null
+++ test/ELF/linkerscript/zcommon-page-size.s
@@ -0,0 +1,14 @@
+# REQUIRES: x86
+# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t
+
+# RUN: echo "SECTIONS { \
+# RUN:         symbol = CONSTANT(COMMONPAGESIZE); \
+# RUN:       }" > %t.script
+# RUN: ld.lld -z common-page-size=0x1234 -o %t1 --script %t.script %t
+# RUN: llvm-objdump -t %t1 | FileCheck %s
+
+# CHECK: 0000000000001234 *ABS* 00000000 symbol
+
+.global _start
+_start:
+ nop
Index: ELF/LinkerScript.cpp
===================================================================
--- ELF/LinkerScript.cpp
+++ ELF/LinkerScript.cpp
@@ -1414,7 +1414,7 @@
 
 uint64_t static getConstant(StringRef S) {
   if (S == "COMMONPAGESIZE")
-    return Target->PageSize;
+    return Config->CommonPageSize;
   if (S == "MAXPAGESIZE")
     return Target->MaxPageSize;
   error("unknown constant: " + S);
Index: ELF/Driver.cpp
===================================================================
--- ELF/Driver.cpp
+++ ELF/Driver.cpp
@@ -646,6 +646,15 @@
   for (auto *Arg : Args.filtered(OPT_trace_symbol))
     Symtab.trace(Arg->getValue());
 
+  // Initialize Config->PageSize. The default value is defined by the
+  // target, but it can be overriden using the -z common-page-size option.
+  if (Optional<StringRef> Value = getZOptionValue(Args, "common-page-size")) {
+    if (Value->getAsInteger(0, Config->CommonPageSize))
+      error("invalid common page size: " + *Value);
+  } else {
+    Config->CommonPageSize = Target->PageSize;
+  }
+
   // Initialize Config->ImageBase.
   if (auto *Arg = Args.getLastArg(OPT_image_base)) {
     StringRef S = Arg->getValue();
Index: ELF/Config.h
===================================================================
--- ELF/Config.h
+++ ELF/Config.h
@@ -132,6 +132,7 @@
   UnresolvedPolicy UnresolvedSymbols;
   BuildIdKind BuildId = BuildIdKind::None;
   ELFKind EKind = ELFNoneKind;
+  uint64_t CommonPageSize;
   uint16_t DefaultSymbolVersion = llvm::ELF::VER_NDX_GLOBAL;
   uint16_t EMachine = llvm::ELF::EM_NONE;
   uint64_t EntryAddr = 0;


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