f2916becc5
In many cases, we can use an alias to avoid a symbolic relocations, instead of using the public, interposable symbol. When the instrumented function is in a COMDAT, we can use a hidden alias, and still avoid references to discarded sections. Previous versions of this patch allowed the compiler to name the generated alias, but that would only be valid when the functions were local. Since the alias may be used across TUs we use a more deterministic naming convention, and add a ".local" suffix to the alias name just as we do for relative vtables aliases. https://reviews.llvm.org/rG20894a478da224bdd69c91a22a5175b28bc08ed9 removed an incorrect assertion on Mach-O which caused assertion failures in LLD. We prevent duplicate symbols under ThinLTO + PGO + CFI by disabling alias generation when the target function has MD_type metadata used in CFI. Reviewed By: phosek Differential Revision: https://reviews.llvm.org/D137982
52 lines
1.3 KiB
C++
52 lines
1.3 KiB
C++
// Check that instrprof does not introduce references to discarded sections when
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// using comdats.
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//
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// Occasionally, it is possible that the same function can be compiled in
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// different TUs with slightly different linkages, e.g., due to different
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// compiler options. However, if these are comdat functions, a single
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// implementation will be chosen at link time. we want to ensure that the
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// profiling data does not contain a reference to the discarded section.
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// UNSUPPORTED: target={{.*windows.*}}
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// RUN: mkdir -p %t.d
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// RUN: %clangxx_pgogen -O2 -fPIC -ffunction-sections -fdata-sections -c %s -o %t.d/a1.o -DOBJECT_1 -mllvm -disable-preinline
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// RUN: %clangxx_pgogen -O2 -fPIC -ffunction-sections -fdata-sections -c %s -o %t.d/a2.o
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// RUN: %clangxx_pgogen -fPIC -shared -o %t.d/liba.so %t.d/a1.o %t.d/a2.o 2>&1 | FileCheck %s --allow-empty
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// Ensure that we don't get an error when linking
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// CHECK-NOT: relocation refers to a discarded section: .text._ZN1CIiE1fEi
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template <typename T> struct C {
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void f(T x);
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int g(T x) {
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f(x);
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return v;
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}
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int v;
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};
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template <typename T>
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#ifdef OBJECT_1
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__attribute__((weak))
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#else
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__attribute__((noinline))
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#endif
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void C<T>::f(T x) {
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v += x;
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}
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#ifdef OBJECT_1
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int foo() {
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C<int> c;
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c.f(1);
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return c.g(2);
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}
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#else
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int bar() {
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C<int> c;
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c.f(3);
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return c.g(4);
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}
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#endif
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