[PATCH] D60719: Demonstrate how to fix freestanding for memcpy
Guillaume Chatelet via Phabricator via cfe-commits
cfe-commits at lists.llvm.org
Tue Apr 16 06:47:09 PDT 2019
gchatelet updated this revision to Diff 195369.
gchatelet added a comment.
Add test.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D60719/new/
https://reviews.llvm.org/D60719
Files:
clang/lib/CodeGen/CodeGenModule.cpp
clang/test/CodeGen/freestanding-disables-libc.c
llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
Index: llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
===================================================================
--- llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -5480,6 +5480,14 @@
}
}
+static bool IsForceInlineLibc(const SelectionDAG &DAG) {
+ const Module *M = DAG.getMachineFunction().getFunction().getParent();
+ if (auto *MD = mdconst::extract_or_null<ConstantInt>(
+ M->getModuleFlag("force-inline-libc")))
+ return MD->getZExtValue();
+ return false;
+}
+
/// Lower the call to the specified intrinsic function. If we want to emit this
/// as a call to a named external function, return the name. Otherwise, lower it
/// and return null.
@@ -5553,10 +5561,11 @@
unsigned Align = MinAlign(DstAlign, SrcAlign);
bool isVol = MCI.isVolatile();
bool isTC = I.isTailCall() && isInTailCallPosition(&I, DAG.getTarget());
+ bool IsAlwaysInline = IsForceInlineLibc(DAG);
// FIXME: Support passing different dest/src alignments to the memcpy DAG
// node.
SDValue MC = DAG.getMemcpy(getRoot(), sdl, Op1, Op2, Op3, Align, isVol,
- false, isTC,
+ IsAlwaysInline, isTC,
MachinePointerInfo(I.getArgOperand(0)),
MachinePointerInfo(I.getArgOperand(1)));
updateDAGForMaybeTailCall(MC);
Index: llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
===================================================================
--- llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -6090,6 +6090,9 @@
// beyond the given memory regions. But fixing this isn't easy, and most
// people don't care.
+ assert(MF->getFunction().getParent()->getModuleFlag("force-inline-libc") ==
+ nullptr);
+
// Emit a library call.
TargetLowering::ArgListTy Args;
TargetLowering::ArgListEntry Entry;
Index: clang/test/CodeGen/freestanding-disables-libc.c
===================================================================
--- /dev/null
+++ clang/test/CodeGen/freestanding-disables-libc.c
@@ -0,0 +1,11 @@
+// NOTE: Test that IR module specifies a "force-inline-libc" attribute in freestanding mode.
+// RUN: %clang_cc1 -triple i386-unknown-unknown -emit-llvm %s -o - | not grep 'force-inline-libc'
+// RUN: %clang_cc1 -triple i386-unknown-unknown -O2 -emit-llvm %s -o - | not grep 'force-inline-libc'
+// RUN: %clang_cc1 -triple i386-unknown-unknown -ffreestanding -O2 -emit-llvm %s -o - | grep 'force-inline-libc'
+
+// NOTE: Test that assembly doesn't call memcpy function in freestanding mode.
+// RUN: %clang_cc1 -triple i386-unknown-unknown -O2 -S %s -o - | grep 'memcpy'
+// RUN: %clang_cc1 -triple i386-unknown-unknown -ffreestanding -O2 -S %s -o - | not grep 'memcpy'
+
+struct BigStruct { char payload[4096]; };
+struct BigStruct PassByValue(struct BigStruct value) { return value; }
Index: clang/lib/CodeGen/CodeGenModule.cpp
===================================================================
--- clang/lib/CodeGen/CodeGenModule.cpp
+++ clang/lib/CodeGen/CodeGenModule.cpp
@@ -596,6 +596,10 @@
if (!getCodeGenOpts().RecordCommandLine.empty())
EmitCommandLineMetadata();
+ if (LangOpts.Freestanding) {
+ getModule().addModuleFlag(llvm::Module::Override, "force-inline-libc", 1);
+ }
+
EmitTargetMetadata();
}
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