Add @llvm.clear_cache builtin

Implementing the LLVM part of the call to __builtin___clear_cache
which translates into an intrinsic @llvm.clear_cache and is lowered
by each target, either to a call to __clear_cache or nothing at all
incase the caches are unified.

Updating LangRef and adding some tests for the implemented architectures.
Other archs will have to implement the method in case this builtin
has to be compiled for it, since the default behaviour is to bail
unimplemented.

A Clang patch is required for the builtin to be lowered into the
llvm intrinsic. This will be done next.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204802 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/docs/LangRef.rst b/docs/LangRef.rst
index c959f56ef1168c3b85b26a0222c7a50de9dee5c9..d18d4ebac9089936335c384fa9ce1b185bbb4952 100644 (file)
--- a/docs/LangRef.rst
+++ b/docs/LangRef.rst
@@ -6939,6 +6939,36 @@ is lowered to a constant 0.
 Note that runtime support may be conditional on the privilege-level code is
 running at and the host platform.
 
+'``llvm.clear_cache``' Intrinsic
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Syntax:
+"""""""
+
+::
+
+      declare void @llvm.clear_cache(i8*, i8*)
+
+Overview:
+"""""""""
+
+The '``llvm.clear_cache``' intrinsic provides access to the systemcall
+that flushes the cache at the range specified. Some targets need this
+to specifically flush the instruction cache when executable data changes
+in memory (self-modifying code). Other targets have unified intruction
+and data cache, so they don't need any calls.
+
+Semantics:
+""""""""""
+
+When directly supported, this intrinsic will either return a call to
+the appropriate cache clearing system call (usually ``__clear_cache``)
+when the caches are not unified (ARM, Mips) or just remove the call
+altogether when they are (ex. x86_64).
+
+Targets must implement it directly to have either behaviour, as the
+default is to bail with "Not Implemented" message.
+
 Standard C Library Intrinsics
 -----------------------------
 

diff --git a/include/llvm/IR/Intrinsics.td b/include/llvm/IR/Intrinsics.td
index 94c7b50ac8e30ce828a8e9fe30b0c67825ff3192..0c9cc3be3d79cd9316bcc2068e4f97c7018c75bc 100644 (file)
--- a/include/llvm/IR/Intrinsics.td
+++ b/include/llvm/IR/Intrinsics.td
@@ -513,6 +513,11 @@ def int_convertus  : Intrinsic<[llvm_anyint_ty],
 def int_convertuu  : Intrinsic<[llvm_anyint_ty],
                                [llvm_anyint_ty, llvm_i32_ty, llvm_i32_ty]>;
 
+// Clear cache intrinsic, default to ignore (ie. emit nothing)
+// maps to void __clear_cache() on supporting platforms
+def int_clear_cache : Intrinsic<[], [llvm_ptr_ty, llvm_ptr_ty],
+                                [], "llvm.clear_cache">;
+
 //===----------------------------------------------------------------------===//
 // Target-specific intrinsics
 //===----------------------------------------------------------------------===//

diff --git a/include/llvm/Target/TargetLowering.h b/include/llvm/Target/TargetLowering.h
index 8f00ac8fa336b32b5bd7861a73e01b222aa421fd..fbc8b74e9e7aad5d7d7b13cbfcc26b146998a590 100644 (file)
--- a/include/llvm/Target/TargetLowering.h
+++ b/include/llvm/Target/TargetLowering.h
@@ -2108,6 +2108,11 @@ public:
     return false;
   }
 
+  /// Return the builtin name for the __builtin___clear_cache intrinsic
+  virtual const char * getClearCacheBuiltinName() const {
+    llvm_unreachable("Not Implemented");
+  }
+
   /// Return the type that should be used to zero or sign extend a
   /// zeroext/signext integer argument or return value.  FIXME: Most C calling
   /// convention requires the return type to be promoted, but this is not true

diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index bd80a503e217f5a447f0da1e4e8f8ad5537fa095..639ff82ffd3aa3b65800510983fcfaed5234fd42 100644 (file)
--- a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -5386,6 +5386,8 @@ SelectionDAGBuilder::visitIntrinsicCall(const CallInst &I, unsigned Intrinsic) {
     (void)getControlRoot();
     return 0;
   }
+  case Intrinsic::clear_cache:
+    return TLI->getClearCacheBuiltinName();
   case Intrinsic::donothing:
     // ignore
     return 0;

diff --git a/lib/Target/ARM/ARMISelLowering.h b/lib/Target/ARM/ARMISelLowering.h
index 022945f625afd6292e10f3cb519b16b7adbb3131..5f6ea754348c395e2c56f299a8bf1aae7cf848af 100644 (file)
--- a/lib/Target/ARM/ARMISelLowering.h
+++ b/lib/Target/ARM/ARMISelLowering.h
@@ -384,6 +384,11 @@ namespace llvm {
     bool shouldConvertConstantLoadToIntImm(const APInt &Imm,
                                            Type *Ty) const override;
 
+    /// Clear cache library call
+    const char * getClearCacheBuiltinName() const {
+      return "__clear_cache";
+    }
+
   protected:
     std::pair<const TargetRegisterClass*, uint8_t>
     findRepresentativeClass(MVT VT) const override;

diff --git a/lib/Target/Mips/MipsISelLowering.h b/lib/Target/Mips/MipsISelLowering.h
index 27492a8046cc244897fb024b5a9d997317d55919..b03cccfb5864a1a7b2a8f4405f2d0c9ce0d8504e 100644 (file)
--- a/lib/Target/Mips/MipsISelLowering.h
+++ b/lib/Target/Mips/MipsISelLowering.h
@@ -583,6 +583,11 @@ namespace llvm {
                                     bool MemcpyStrSrc,
                                     MachineFunction &MF) const;
 
+    /// Clear cache library call
+    const char * getClearCacheBuiltinName() const {
+      return "__clear_cache";
+    }
+
     /// isFPImmLegal - Returns true if the target can instruction select the
     /// specified FP immediate natively. If false, the legalizer will
     /// materialize the FP immediate as a load from a constant pool.

diff --git a/lib/Target/X86/X86ISelLowering.h b/lib/Target/X86/X86ISelLowering.h
index 894cfc6d0c136380f6ec4c2be6dae7ad1250ec9e..ae13ca491cb6a19762fb7aad34183a0d39aed627 100644 (file)
--- a/lib/Target/X86/X86ISelLowering.h
+++ b/lib/Target/X86/X86ISelLowering.h
@@ -770,6 +770,11 @@ namespace llvm {
     bool shouldConvertConstantLoadToIntImm(const APInt &Imm,
                                            Type *Ty) const override;
 
+    /// Intel processors have a unified instruction and data cache
+    const char * getClearCacheBuiltinName() const {
+      return 0; // nothing to do, move along.
+    }
+
     /// createFastISel - This method returns a target specific FastISel object,
     /// or null if the target does not support "fast" ISel.
     FastISel *createFastISel(FunctionLoweringInfo &funcInfo,

diff --git a/test/CodeGen/ARM/cache-intrinsic.ll b/test/CodeGen/ARM/cache-intrinsic.ll
new file mode 100644 (file)
index 0000000..6048917
--- /dev/null
+++ b/test/CodeGen/ARM/cache-intrinsic.ll
@@ -0,0 +1,26 @@
+; RUN: llc %s -o - | FileCheck %s
+target datalayout = "e-m:e-p:32:32-i64:64-v128:64:128-n32-S64"
+target triple = "armv7--linux-gnueabihf"
+
+@buffer = global [32 x i8] c"This is a largely unused buffer\00", align 1
+@.str = private unnamed_addr constant [4 x i8] c"%s\0A\00", align 1
+@.str1 = private unnamed_addr constant [25 x i8] c"Still, largely unused...\00", align 1
+
+define i32 @main() {
+entry:
+  %retval = alloca i32, align 4
+  store i32 0, i32* %retval
+  %call = call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([4 x i8]* @.str, i32 0, i32 0), i8* getelementptr inbounds ([32 x i8]* @buffer, i32 0, i32 0))
+  %call1 = call i8* @strcpy(i8* getelementptr inbounds ([32 x i8]* @buffer, i32 0, i32 0), i8* getelementptr inbounds ([25 x i8]* @.str1, i32 0, i32 0)) #3
+  call void @llvm.clear_cache(i8* getelementptr inbounds ([32 x i8]* @buffer, i32 0, i32 0), i8* getelementptr inbounds (i8* getelementptr inbounds ([32 x i8]* @buffer, i32 0, i32 0), i32 32)) #3
+  %call2 = call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([4 x i8]* @.str, i32 0, i32 0), i8* getelementptr inbounds ([32 x i8]* @buffer, i32 0, i32 0))
+  ret i32 0
+}
+
+; CHECK: __clear_cache
+
+declare i32 @printf(i8*, ...)
+
+declare i8* @strcpy(i8*, i8*)
+
+declare void @llvm.clear_cache(i8*, i8*)

diff --git a/test/CodeGen/Mips/cache-intrinsic.ll b/test/CodeGen/Mips/cache-intrinsic.ll
new file mode 100644 (file)
index 0000000..2fa4115
--- /dev/null
+++ b/test/CodeGen/Mips/cache-intrinsic.ll
@@ -0,0 +1,26 @@
+; RUN: llc %s -o - | FileCheck %s
+target datalayout = "E-p:32:32:32-i1:8:8-i8:8:32-i16:16:32-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-n32-S64"
+target triple = "mips--linux-gnu"
+
+@buffer = global [32 x i8] c"This is a largely unused buffer\00", align 1
+@.str = private unnamed_addr constant [4 x i8] c"%s\0A\00", align 1
+@.str1 = private unnamed_addr constant [25 x i8] c"Still, largely unused...\00", align 1
+
+define i32 @main() {
+entry:
+  %retval = alloca i32, align 4
+  store i32 0, i32* %retval
+  %call = call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([4 x i8]* @.str, i32 0, i32 0), i8* getelementptr inbounds ([32 x i8]* @buffer, i32 0, i32 0))
+  %call1 = call i8* @strcpy(i8* getelementptr inbounds ([32 x i8]* @buffer, i32 0, i32 0), i8* getelementptr inbounds ([25 x i8]* @.str1, i32 0, i32 0)) #3
+  call void @llvm.clear_cache(i8* getelementptr inbounds ([32 x i8]* @buffer, i32 0, i32 0), i8* getelementptr inbounds (i8* getelementptr inbounds ([32 x i8]* @buffer, i32 0, i32 0), i32 32)) #3
+  %call2 = call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([4 x i8]* @.str, i32 0, i32 0), i8* getelementptr inbounds ([32 x i8]* @buffer, i32 0, i32 0))
+  ret i32 0
+}
+
+; CHECK: __clear_cache
+
+declare i32 @printf(i8*, ...)
+
+declare i8* @strcpy(i8*, i8*)
+
+declare void @llvm.clear_cache(i8*, i8*)

diff --git a/test/CodeGen/X86/cache-intrinsic.ll b/test/CodeGen/X86/cache-intrinsic.ll
new file mode 100644 (file)
index 0000000..3091b5f
--- /dev/null
+++ b/test/CodeGen/X86/cache-intrinsic.ll
@@ -0,0 +1,26 @@
+; RUN: llc %s -o - | FileCheck %s
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+@buffer = global [32 x i8] c"This is a largely unused buffer\00", align 16
+@.str = private unnamed_addr constant [4 x i8] c"%s\0A\00", align 1
+@.str1 = private unnamed_addr constant [25 x i8] c"Still, largely unused...\00", align 1
+
+define i32 @main() {
+entry:
+  %retval = alloca i32, align 4
+  store i32 0, i32* %retval
+  %call = call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([4 x i8]* @.str, i32 0, i32 0), i8* getelementptr inbounds ([32 x i8]* @buffer, i32 0, i32 0))
+  %call1 = call i8* @strcpy(i8* getelementptr inbounds ([32 x i8]* @buffer, i32 0, i32 0), i8* getelementptr inbounds ([25 x i8]* @.str1, i32 0, i32 0)) #3
+  call void @llvm.clear_cache(i8* getelementptr inbounds ([32 x i8]* @buffer, i32 0, i32 0), i8* getelementptr inbounds (i8* getelementptr inbounds ([32 x i8]* @buffer, i32 0, i32 0), i32 32)) #3
+  %call3 = call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([4 x i8]* @.str, i32 0, i32 0), i8* getelementptr inbounds ([32 x i8]* @buffer, i32 0, i32 0))
+  ret i32 0
+}
+
+; CHECK-NOT: __clear_cache
+
+declare i32 @printf(i8*, ...)
+
+declare i8* @strcpy(i8*, i8*)
+
+declare void @llvm.clear_cache(i8*, i8*)