[llvm] 456ffd7 - [OpenMP] Ensure offloading sections do not have SHF_ALLOC flag

[Joseph Huber via llvm-commits]

Author: Joseph Huber
Date: 2022-02-21T21:35:17-05:00
New Revision: 456ffd7a225f908ca61d747be21439f6182ea40c

URL: https://github.com/llvm/llvm-project/commit/456ffd7a225f908ca61d747be21439f6182ea40c
DIFF: https://github.com/llvm/llvm-project/commit/456ffd7a225f908ca61d747be21439f6182ea40c.diff

LOG: [OpenMP] Ensure offloading sections do not have SHF_ALLOC flag

We use offloading sections in the new Clang driver scheme to embed
device code into the host. We later use these sections to link the
device image, after which point they are completely unused and should
not be loaded into memory if they are still in the executable.

Reviewed By: JonChesterfield

Differential Revision: https://reviews.llvm.org/D120275

Added: 
    llvm/test/CodeGen/X86/offload_sections.ll

Modified: 
    llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp

Removed: 
    


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diff  --git a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
index 0892c74a7a24b..348470bd7687d 100644
--- a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
+++ b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
@@ -446,7 +446,8 @@ static SectionKind getELFKindForNamedSection(StringRef Name, SectionKind K) {
                                       /*AddSegmentInfo=*/false) ||
       Name == getInstrProfSectionName(IPSK_covfun, Triple::ELF,
                                       /*AddSegmentInfo=*/false) ||
-      Name == ".llvmbc" || Name == ".llvmcmd")
+      Name == ".llvmbc" || Name == ".llvmcmd" ||
+      Name.startswith(".llvm.offloading."))
     return SectionKind::getMetadata();
 
   if (Name.empty() || Name[0] != '.') return K;

diff  --git a/llvm/test/CodeGen/X86/offload_sections.ll b/llvm/test/CodeGen/X86/offload_sections.ll
new file mode 100644
index 0000000000000..dcd6dcb7cf3fc
--- /dev/null
+++ b/llvm/test/CodeGen/X86/offload_sections.ll
@@ -0,0 +1,6 @@
+; RUN: llc < %s -mtriple=x86_64-unknown-linux-gnu | FileCheck %s
+
+ at llvm.embedded.object = hidden constant [1 x i8] c"\00", section ".llvm.offloading.dummy"
+ at llvm.compiler.used = appending global [1 x i8*] [i8* getelementptr inbounds ([1 x i8], [1 x i8]* @llvm.embedded.object, i32 0, i32 0)], section "llvm.metadata"
+
+; CHECK-DAG: .section	.llvm.offloading.dummy,""