[prev in list] [next in list] [prev in thread] [next in thread]
List: cfe-commits
Subject: [PATCH] [ARM] Save option "arm-long-calls" to the IR as a function attribute
From: Akira Hatanaka <ahatanak () gmail ! com>
Date: 2015-04-30 20:00:08
Message-ID: differential-rev-PHID-DREV-bdwri5pfcwbq3rcpbnwq-req () reviews ! llvm ! org
[Download RAW message or body]
Hi echristo, dexonsmith,
This patch is part of the work to make LTO and function multi-versioning work \
correctly.
Currently, -mlong-calls, which is converted to cc1 option -arm-long-calls, is ignored \
when building with LTO because the option isn't passed to the linker or libLTO. This \
patch saves the option in the IR as a function attribute to fix this problem.
The corresponding llvm patch is here:
http://reviews.llvm.org/D9364
There are a few things to discuss:
1. Should "arm-long-calls" be a binary attribute or a tri-state like "unsafe-fp-math" \
that takes a value "true" or "false"? I made it a binary attribute because it \
simplifies the backend and frontend without breaking backward compatibility, but \
might be use cases that I'm unaware of in which this approach wouldn't work.
2. Since we are saving the option in the IR, should we stop passing it as a cc1 \
backend option and stop passing it to llvm::cl::ParseCommandLineOptions? It's not \
needed if this attribute is a tri-state, but is needed if it's a binary to preserve \
backward compatibility. By "backward compatibility", I mean the following commands \
should produce the same result before and after this patch is committed:
1. clang -target armv7-apple-ios -static -mlong-calls old.bc -o old
2. clang -target armv7-apple-ios -static old.bc -o old
Here, old.bc is generated by an older version of clang that doesn't save \
"arm-long-calls" in the IR.
http://reviews.llvm.org/D9414
Files:
include/clang/Frontend/CodeGenOptions.h
lib/CodeGen/CGCall.cpp
lib/Frontend/CompilerInvocation.cpp
test/CodeGen/fn-attr.c
Index: include/clang/Frontend/CodeGenOptions.h
===================================================================
--- include/clang/Frontend/CodeGenOptions.h
+++ include/clang/Frontend/CodeGenOptions.h
@@ -151,6 +151,9 @@
/// A list of command-line options to forward to the LLVM backend.
std::vector<std::string> BackendOptions;
+ /// A list of function attributes to save to the IR.
+ std::vector<std::pair<std::string, std::string>> FunctionAttributes;
+
/// A list of dependent libraries.
std::vector<std::string> DependentLibraries;
Index: lib/CodeGen/CGCall.cpp
===================================================================
--- lib/CodeGen/CGCall.cpp
+++ lib/CodeGen/CGCall.cpp
@@ -1455,6 +1455,9 @@
FuncAttrs.addAttribute(llvm::Attribute::NoBuiltin);
} else {
// Attributes that should go on the function, but not the call site.
+ for (auto &KV : CodeGenOpts.FunctionAttributes)
+ FuncAttrs.addAttribute(KV.first, KV.second);
+
if (!CodeGenOpts.DisableFPElim) {
FuncAttrs.addAttribute("no-frame-pointer-elim", "false");
} else if (CodeGenOpts.OmitLeafFramePointer) {
Index: lib/Frontend/CompilerInvocation.cpp
===================================================================
--- lib/Frontend/CompilerInvocation.cpp
+++ lib/Frontend/CompilerInvocation.cpp
@@ -340,6 +340,14 @@
}
}
+static void getFunctionAttributes(CodeGenOptions &Opts) {
+ StringRef Opt = "-arm-long-calls", Key = Opt.drop_front(1);
+
+ if (std::find(Opts.BackendOptions.begin(), Opts.BackendOptions.end(),
+ Opt) != Opts.BackendOptions.end())
+ Opts.FunctionAttributes.push_back(std::make_pair(Key, ""));
+}
+
static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
DiagnosticsEngine &Diags,
const TargetOptions &TargetOpts) {
@@ -643,6 +651,8 @@
Args.getAllArgValues(OPT_fsanitize_recover_EQ), Diags,
Opts.SanitizeRecover);
+ getFunctionAttributes(Opts);
+
return Success;
}
Index: test/CodeGen/fn-attr.c
===================================================================
--- /dev/null
+++ test/CodeGen/fn-attr.c
@@ -0,0 +1,7 @@
+// RUN: %clang_cc1 -triple thumbv7-apple-ios5 -backend-option -arm-long-calls \
-emit-llvm -o - %s | FileCheck -check-prefix=LONGCALL %s +// RUN: %clang_cc1 -triple \
thumbv7-apple-ios5 -emit-llvm -o - %s | FileCheck -check-prefix=NOLONGCALL %s +
+// LONGCALL: attributes #0 = { {{.*}} "arm-long-calls
+// NOLONGCALL-NOT: attributes #0 = { {{.*}} "arm-long-calls
+
+int foo1(int a) { return a; }
EMAIL PREFERENCES
http://reviews.llvm.org/settings/panel/emailpreferences/
["D9414.24762.patch" (text/x-patch)]
Index: include/clang/Frontend/CodeGenOptions.h
===================================================================
--- include/clang/Frontend/CodeGenOptions.h
+++ include/clang/Frontend/CodeGenOptions.h
@@ -151,6 +151,9 @@
/// A list of command-line options to forward to the LLVM backend.
std::vector<std::string> BackendOptions;
+ /// A list of function attributes to save to the IR.
+ std::vector<std::pair<std::string, std::string>> FunctionAttributes;
+
/// A list of dependent libraries.
std::vector<std::string> DependentLibraries;
Index: lib/CodeGen/CGCall.cpp
===================================================================
--- lib/CodeGen/CGCall.cpp
+++ lib/CodeGen/CGCall.cpp
@@ -1455,6 +1455,9 @@
FuncAttrs.addAttribute(llvm::Attribute::NoBuiltin);
} else {
// Attributes that should go on the function, but not the call site.
+ for (auto &KV : CodeGenOpts.FunctionAttributes)
+ FuncAttrs.addAttribute(KV.first, KV.second);
+
if (!CodeGenOpts.DisableFPElim) {
FuncAttrs.addAttribute("no-frame-pointer-elim", "false");
} else if (CodeGenOpts.OmitLeafFramePointer) {
Index: lib/Frontend/CompilerInvocation.cpp
===================================================================
--- lib/Frontend/CompilerInvocation.cpp
+++ lib/Frontend/CompilerInvocation.cpp
@@ -340,6 +340,14 @@
}
}
+static void getFunctionAttributes(CodeGenOptions &Opts) {
+ StringRef Opt = "-arm-long-calls", Key = Opt.drop_front(1);
+
+ if (std::find(Opts.BackendOptions.begin(), Opts.BackendOptions.end(),
+ Opt) != Opts.BackendOptions.end())
+ Opts.FunctionAttributes.push_back(std::make_pair(Key, ""));
+}
+
static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
DiagnosticsEngine &Diags,
const TargetOptions &TargetOpts) {
@@ -643,6 +651,8 @@
Args.getAllArgValues(OPT_fsanitize_recover_EQ), Diags,
Opts.SanitizeRecover);
+ getFunctionAttributes(Opts);
+
return Success;
}
Index: test/CodeGen/fn-attr.c
===================================================================
--- /dev/null
+++ test/CodeGen/fn-attr.c
@@ -0,0 +1,7 @@
+// RUN: %clang_cc1 -triple thumbv7-apple-ios5 -backend-option -arm-long-calls \
-emit-llvm -o - %s | FileCheck -check-prefix=LONGCALL %s +// RUN: %clang_cc1 -triple \
thumbv7-apple-ios5 -emit-llvm -o - %s | FileCheck -check-prefix=NOLONGCALL %s +
+// LONGCALL: attributes #0 = { {{.*}} "arm-long-calls
+// NOLONGCALL-NOT: attributes #0 = { {{.*}} "arm-long-calls
+
+int foo1(int a) { return a; }
_______________________________________________
cfe-commits mailing list
cfe-commits@cs.uiuc.edu
http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits
[prev in list] [next in list] [prev in thread] [next in thread]
Configure |
About |
News |
Add a list |
Sponsored by KoreLogic