ahatanak created this revision.
ahatanak added reviewers: echristo, dexonsmith, jfb, dschuff.
ahatanak added a subscriber: cfe-commits.
Herald added subscribers: rengolin, jfb, aemerson.
This is change is needed for LTO since anything passed via backend-option does
not make it to the backend.
The corresponding llvm patch is here: http://reviews.llvm.org/D11470
http://reviews.llvm.org/D11472
Files:
lib/Driver/Tools.cpp
test/Driver/apple-kext-mkernel.c
test/Driver/arm-alignment.c
Index: test/Driver/arm-alignment.c
===================================================================
--- test/Driver/arm-alignment.c
+++ test/Driver/arm-alignment.c
@@ -16,7 +16,7 @@
// RUN: %clang -target aarch64-none-gnueabi -mno-unaligned-access -munaligned-access -### %s 2> %t
// RUN: FileCheck --check-prefix=CHECK-UNALIGNED-AARCH64 < %t %s
-// CHECK-UNALIGNED-ARM: "-backend-option" "-arm-no-strict-align"
+// CHECK-UNALIGNED-ARM-NOT: "-target-feature" "+strict-align"
// CHECK-UNALIGNED-AARCH64: "-backend-option" "-aarch64-no-strict-align"
@@ -47,7 +47,7 @@
// RUN: %clang -target aarch64-none-gnueabi -mkernel -mno-unaligned-access -### %s 2> %t
// RUN: FileCheck --check-prefix=CHECK-ALIGNED-AARCH64 < %t %s
-// CHECK-ALIGNED-ARM: "-backend-option" "-arm-strict-align"
+// CHECK-ALIGNED-ARM: "-target-feature" "+strict-align"
// CHECK-ALIGNED-AARCH64: "-backend-option" "-aarch64-strict-align"
// Make sure that v6M cores always trigger the unsupported aligned accesses error
Index: test/Driver/apple-kext-mkernel.c
===================================================================
--- test/Driver/apple-kext-mkernel.c
+++ test/Driver/apple-kext-mkernel.c
@@ -12,8 +12,8 @@
// RUN: FileCheck --check-prefix=CHECK-ARM < %t %s
// CHECK-ARM: "-target-feature" "+long-calls"
-// CHECK-ARM: "-backend-option" "-arm-strict-align"
-// CHECK-ARM-NOT: "-backend-option" "-arm-strict-align"
+// CHECK-ARM: "-target-feature" "+strict-align"
+// CHECK-ARM-NOT: "-target-feature" "+strict-align"
// CHECK-ARM: "-fno-builtin"
// CHECK-ARM: "-fno-rtti"
// CHECK-ARM: "-fno-common"
Index: lib/Driver/Tools.cpp
===================================================================
--- lib/Driver/Tools.cpp
+++ lib/Driver/Tools.cpp
@@ -719,6 +719,42 @@
Features.push_back("+long-calls");
}
+ // Kernel code has more strict alignment requirements.
+ if (KernelOrKext)
+ Features.push_back("+strict-align");
+ else if (Arg *A = Args.getLastArg(options::OPT_mno_unaligned_access,
+ options::OPT_munaligned_access)) {
+ if (A->getOption().matches(options::OPT_munaligned_access)) {
+ // No v6M core supports unaligned memory access (v6M ARM ARM A3.2).
+ if (Triple.getSubArch() == llvm::Triple::SubArchType::ARMSubArch_v6m)
+ D.Diag(diag::err_target_unsupported_unaligned) << "v6m";
+ } else
+ Features.push_back("+strict-align");
+ } else {
+ // Assume pre-ARMv6 doesn't support unaligned accesses.
+ //
+ // ARMv6 may or may not support unaligned accesses depending on the
+ // SCTLR.U bit, which is architecture-specific. We assume ARMv6
+ // Darwin and NetBSD targets support unaligned accesses, and others don't.
+ //
+ // ARMv7 always has SCTLR.U set to 1, but it has a new SCTLR.A bit
+ // which raises an alignment fault on unaligned accesses. Linux
+ // defaults this bit to 0 and handles it as a system-wide (not
+ // per-process) setting. It is therefore safe to assume that ARMv7+
+ // Linux targets support unaligned accesses. The same goes for NaCl.
+ //
+ // The above behavior is consistent with GCC.
+ int VersionNum = getARMSubArchVersionNumber(Triple);
+ if (Triple.isOSDarwin() || Triple.isOSNetBSD()) {
+ if (VersionNum < 6)
+ Features.push_back("+strict-align");
+ } else if (Triple.isOSLinux() || Triple.isOSNaCl()) {
+ if (VersionNum < 7)
+ Features.push_back("+strict-align");
+ } else
+ Features.push_back("+strict-align");
+ }
+
// llvm does not support reserving registers in general. There is support
// for reserving r9 on ARM though (defined as a platform-specific register
// in ARM EABI).
@@ -799,27 +835,6 @@
CmdArgs.push_back("hard");
}
- // Kernel code has more strict alignment requirements.
- if (KernelOrKext) {
- CmdArgs.push_back("-backend-option");
- CmdArgs.push_back("-arm-strict-align");
- }
-
- // -mkernel implies -mstrict-align; don't add the redundant option.
- if (!KernelOrKext) {
- if (Arg *A = Args.getLastArg(options::OPT_mno_unaligned_access,
- options::OPT_munaligned_access)) {
- CmdArgs.push_back("-backend-option");
- if (A->getOption().matches(options::OPT_mno_unaligned_access))
- CmdArgs.push_back("-arm-strict-align");
- else {
- if (Triple.getSubArch() == llvm::Triple::SubArchType::ARMSubArch_v6m)
- D.Diag(diag::err_target_unsupported_unaligned) << "v6m";
- CmdArgs.push_back("-arm-no-strict-align");
- }
- }
- }
-
// Forward the -mglobal-merge option for explicit control over the pass.
if (Arg *A = Args.getLastArg(options::OPT_mglobal_merge,
options::OPT_mno_global_merge)) {
_______________________________________________
cfe-commits mailing list
[email protected]
http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits
