[PATCH] D77746: [Driver] Default arm-linux-androideabi to -z max-page-size=4096

[Fangrui Song via Phabricator via cfe-commits]

MaskRay created this revision.
MaskRay added reviewers: rprichard, srhines, thieta.
Herald added subscribers: cfe-commits, danielkiss, kristof.beyls.
Herald added a project: clang.

Similar to D55029 <https://reviews.llvm.org/D55029>. The requirement arises when discussing increasing
default max-page-size for lld ARM (D77330 <https://reviews.llvm.org/D77330>).

For the record, the default max-page-size on the 3 commonly used linkers:

- GNU ld since

https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=7572ca8989ead4c3425a1500bc241eaaeffa2c89
defaults to 65536

- GNU gold remains 4096
- lld currently uses 4096 but may increase to 65536 (D77330 <https://reviews.llvm.org/D77330>)


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D77746

Files:
  clang/lib/Driver/ToolChains/Linux.cpp
  clang/test/Driver/android-aarch64-link.cpp
  clang/test/Driver/android-link.cpp


Index: clang/test/Driver/android-link.cpp
===================================================================
--- clang/test/Driver/android-link.cpp
+++ clang/test/Driver/android-link.cpp
@@ -1,4 +1,7 @@
-// Check that we automatically add relevant linker flags for Android aarch64.
+// Check that we add relevant linker flags for Android ARM/AArch64.
+
+// RUN: %clang -### -target arm-linux-androideabi %s 2>&1 | \
+// RUN:   FileCheck --check-prefix=MAX-PAGE-SIZE %s
 
 // RUN: %clang -target aarch64-none-linux-android \
 // RUN:   -### -v %s 2> %t
@@ -19,4 +22,4 @@
 // GENERIC-ARM: --fix-cortex-a53-843419
 // CORTEX-A53: --fix-cortex-a53-843419
 // CORTEX-A57-NOT: --fix-cortex-a53-843419
-// MAX-PAGE-SIZE: max-page-size=4096
+// MAX-PAGE-SIZE: "-z" "max-page-size=4096"
Index: clang/lib/Driver/ToolChains/Linux.cpp
===================================================================
--- clang/lib/Driver/ToolChains/Linux.cpp
+++ clang/lib/Driver/ToolChains/Linux.cpp
@@ -253,10 +253,9 @@
     ExtraOpts.push_back("relro");
   }
 
-  // The lld default page size is too large for Aarch64, which produces much
-  // larger .so files and images for arm64 device targets. Use 4KB page size
-  // for Android arm64 targets instead.
-  if (Triple.isAArch64() && Triple.isAndroid()) {
+  // Android ARM/AArch64 use max-page-size=4096 to reduce VMA usage. Note, the
+  // lld default for both ARM/AArch64 is 65536.
+  if ((Triple.isARM() || Triple.isAArch64()) && Triple.isAndroid()) {
     ExtraOpts.push_back("-z");
     ExtraOpts.push_back("max-page-size=4096");
   }


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