Author: Gulfem Savrun Yeniceri Date: 2022-03-25T17:03:03Z New Revision: c7f91e227a799dfee05962bb108274dbfe809fee
URL: https://github.com/llvm/llvm-project/commit/c7f91e227a799dfee05962bb108274dbfe809fee DIFF: https://github.com/llvm/llvm-project/commit/c7f91e227a799dfee05962bb108274dbfe809fee.diff LOG: [InstrProfiling] No runtime hook for unused funcs CoverageMappingModuleGen generates a coverage mapping record even for unused functions with internal linkage, e.g. static int foo() { return 100; } Clang frontend eliminates such functions, but InstrProfiling pass still pulls in profile runtime since there is a coverage record. Fuchsia uses runtime counter relocation, and pulling in profile runtime for unused functions causes a linker error: undefined hidden symbol: __llvm_profile_counter_bias. Since 389dc94d4be7, we do not hook profile runtime for the binaries that none of its translation units have been instrumented in Fuchsia. This patch extends that for the instrumented binaries that consist of only unused functions. Differential Revision: https://reviews.llvm.org/D122336 Added: clang/test/CoverageMapping/unused_function_no_runtime_hook.cpp Modified: llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp Removed: ################################################################################ diff --git a/clang/test/CoverageMapping/unused_function_no_runtime_hook.cpp b/clang/test/CoverageMapping/unused_function_no_runtime_hook.cpp new file mode 100644 index 0000000000000..5a835ae311697 --- /dev/null +++ b/clang/test/CoverageMapping/unused_function_no_runtime_hook.cpp @@ -0,0 +1,6 @@ +// RUN: %clang -target x86_64-unknown-fuchsia -fprofile-instr-generate -fcoverage-mapping -emit-llvm -S %s -o - | FileCheck %s + +// CHECK-NOT: @__llvm_profile_runtime +static int f0() { + return 100; +} diff --git a/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp b/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp index 379c41ce66936..a8b013b6f2e6a 100644 --- a/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp +++ b/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp @@ -558,16 +558,18 @@ bool InstrProfiling::run( TT = Triple(M.getTargetTriple()); bool MadeChange = false; - - // Emit the runtime hook even if no counters are present. - if (needsRuntimeHookUnconditionally(TT)) + bool NeedsRuntimeHook = needsRuntimeHookUnconditionally(TT); + if (NeedsRuntimeHook) MadeChange = emitRuntimeHook(); // Improve compile time by avoiding linear scans when there is no work. GlobalVariable *CoverageNamesVar = M.getNamedGlobal(getCoverageUnusedNamesVarName()); - if (!containsProfilingIntrinsics(M) && !CoverageNamesVar) - return MadeChange; + if (!containsProfilingIntrinsics(M)) { + if (!CoverageNamesVar || !NeedsRuntimeHook) { + return MadeChange; + } + } // We did not know how many value sites there would be inside // the instrumented function. This is counting the number of instrumented _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
