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46 lines
2.3 KiB
Diff
46 lines
2.3 KiB
Diff
Index: llvm-toolchain-snapshot_3.8~svn249699/clang/lib/Basic/Targets.cpp
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===================================================================
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--- llvm-toolchain-snapshot_3.8~svn249699.orig/clang/lib/Basic/Targets.cpp
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+++ llvm-toolchain-snapshot_3.8~svn249699/clang/lib/Basic/Targets.cpp
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@@ -4330,6 +4330,20 @@ class ARMTargetInfo : public TargetInfo
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}
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}
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+ static bool shouldUseInlineAtomic(const llvm::Triple &T) {
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+ // On linux, binaries targeting old cpus call functions in libgcc to
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+ // perform atomic operations. The implementation in libgcc then calls into
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+ // the kernel which on armv6 and newer uses ldrex and strex. The net result
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+ // is that if we assume the kernel is at least as recent as the hardware,
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+ // it is safe to use atomic instructions on armv6 and newer.
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+ if (T.getOS() != llvm::Triple::Linux)
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+ return false;
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+ StringRef ArchName = T.getArchName();
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+ if (ArchName.startswith("armv6") || ArchName.startswith("armv7"))
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+ return true;
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+ return false;
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+ }
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+
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public:
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ARMTargetInfo(const llvm::Triple &Triple, bool IsBigEndian)
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: TargetInfo(Triple), FPMath(FP_Default),
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Index: llvm-toolchain-snapshot_3.8~svn249699/clang/test/CodeGen/linux-arm-atomic.c
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===================================================================
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--- llvm-toolchain-snapshot_3.8~svn249699.orig/clang/test/CodeGen/linux-arm-atomic.c
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+++ llvm-toolchain-snapshot_3.8~svn249699/clang/test/CodeGen/linux-arm-atomic.c
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@@ -1,5 +1,15 @@
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// RUN: %clang_cc1 %s -emit-llvm -o - -triple=armv7-unknown-linux | FileCheck %s
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// RUN: %clang_cc1 %s -emit-llvm -o - -triple=armv6-unknown-linux | FileCheck %s
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+
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+typedef int _Atomic_word;
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+_Atomic_word exchange_and_add(volatile _Atomic_word *__mem, int __val) {
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+ return __atomic_fetch_add(__mem, __val, __ATOMIC_ACQ_REL);
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+}
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+
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+// CHECK: define {{.*}} @exchange_and_add
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+// CHECK: atomicrmw {{.*}} add
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+// RUN: %clang_cc1 %s -emit-llvm -o - -triple=armv7-unknown-linux | FileCheck %s
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+// RUN: %clang_cc1 %s -emit-llvm -o - -triple=armv6-unknown-linux | FileCheck %s
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// RUN: %clang_cc1 %s -emit-llvm -o - -triple=thumbv7-unknown-linux | FileCheck %s
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// RUN: %clang_cc1 %s -emit-llvm -o - -triple=armv6-unknown-freebsd | FileCheck %s
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// RUN: %clang_cc1 %s -emit-llvm -o - -triple=armv6-unknown-bitrig | FileCheck %s
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