[llvm-dev] LLVM v6.0 Internalize and GlobalDCE PASS can not work together?
Leslie Zhai via llvm-dev
llvm-dev at lists.llvm.org
Wed Oct 25 19:07:35 PDT 2017
Hi Hal,
Thanks for your hint!
$ /opt/llvm-svn/bin/opt -S -internalize
-internalize-public-api-list=main -globaldce hello3.ll -o
hello3.dce.ll it works :)
But I argue that `main` Function should be inserted into ExternalNames
by default:
Index: lib/Transforms/IPO/Internalize.cpp
===================================================================
--- lib/Transforms/IPO/Internalize.cpp (revision 316540)
+++ lib/Transforms/IPO/Internalize.cpp (working copy)
@@ -61,6 +61,7 @@
if (!APIFile.empty())
LoadFile(APIFile);
ExternalNames.insert(APIList.begin(), APIList.end());
+ ExternalNames.insert("main");
}
bool operator()(const GlobalValue &GV) {
在 2017年10月25日 21:20, Hal Finkel 写道:
> Hi, Leslie,
>
> When you use internalize, you need to provide it with a list of
> symbols to preserve as external (otherwise everything will be
> internalized, including main, and then DCE will remove everything).
> You can use -internalize-public-api-list=main (a comma-separated list)
> or -internalize-public-api-file=some_file_name where some_file_name
> has the list of symbols. See the comments in
> lib/Transforms/IPO/Internalize.cpp.
>
> -Hal
>
> On 10/24/2017 11:22 PM, Leslie Zhai via llvm-dev wrote:
>> Hi LLVM developers,
>>
>> $ cat hello.c
>> #include <stdio.h>
>>
>> void foo() {
>> }
>>
>> int main(int argc, char *argv[]) {
>> for (int i = 0; i < 10; i++) {
>> printf("%d\n", i);
>> }
>> return 0;
>> }
>>
>> $ /opt/llvm-svn/bin/clang --version
>> Fedora clang version 6.0.0 (trunk 316308) (based on LLVM 6.0.0svn)
>> Target: x86_64-redhat-linux
>> Thread model: posix
>> InstalledDir: /opt/llvm-svn/bin
>>
>> $ /opt/llvm-svn/bin/clang -Xclang -disable-O0-optnone -S -emit-llvm
>> hello.c -o hello2.ll
>>
>> $ cat hello2.ll
>> ; ModuleID = 'hello.c'
>> source_filename = "hello.c"
>> target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
>> target triple = "x86_64-unknown-linux-gnu"
>>
>> @.str = private unnamed_addr constant [4 x i8] c"%d\0A\00", align 1
>>
>> ; Function Attrs: noinline nounwind uwtable
>> define void @foo() #0 {
>> entry:
>> ret void
>> }
>>
>> ; Function Attrs: noinline nounwind uwtable
>> define i32 @main(i32 %argc, i8** %argv) #0 {
>> entry:
>> %retval = alloca i32, align 4
>> %argc.addr = alloca i32, align 4
>> %argv.addr = alloca i8**, align 8
>> %i = alloca i32, align 4
>> store i32 0, i32* %retval, align 4
>> store i32 %argc, i32* %argc.addr, align 4
>> store i8** %argv, i8*** %argv.addr, align 8
>> store i32 0, i32* %i, align 4
>> br label %for.cond
>>
>> for.cond: ; preds = %for.inc,
>> %entry
>> %0 = load i32, i32* %i, align 4
>> %cmp = icmp slt i32 %0, 10
>> br i1 %cmp, label %for.body, label %for.end
>>
>> for.body: ; preds = %for.cond
>> %1 = load i32, i32* %i, align 4
>> %call = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([4
>> x i8], [4 x i8]* @.str, i32 0, i32 0), i32 %1)
>> br label %for.inc
>>
>> for.inc: ; preds = %for.body
>> %2 = load i32, i32* %i, align 4
>> %inc = add nsw i32 %2, 1
>> store i32 %inc, i32* %i, align 4
>> br label %for.cond
>>
>> for.end: ; preds = %for.cond
>> ret i32 0
>> }
>>
>> declare i32 @printf(i8*, ...) #1
>>
>> attributes #0 = { noinline nounwind uwtable
>> "correctly-rounded-divide-sqrt-fp-math"="false"
>> "disable-tail-calls"="false" "less-precise-fpmad"="false"
>> "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf"
>> "no-infs-fp-math"="false" "no-jump-tables"="false"
>> "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false"
>> "no-trapping-math"="false" "stack-protector-buffer-size"="8"
>> "target-cpu"="x86-64" "target-features"="+fxsr,+mmx,+sse,+sse2,+x87"
>> "unsafe-fp-math"="false" "use-soft-float"="false" }
>> attributes #1 = { "correctly-rounded-divide-sqrt-fp-math"="false"
>> "disable-tail-calls"="false" "less-precise-fpmad"="false"
>> "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf"
>> "no-infs-fp-math"="false" "no-nans-fp-math"="false"
>> "no-signed-zeros-fp-math"="false" "no-trapping-math"="false"
>> "stack-protector-buffer-size"="8" "target-cpu"="x86-64"
>> "target-features"="+fxsr,+mmx,+sse,+sse2,+x87"
>> "unsafe-fp-math"="false" "use-soft-float"="false" }
>>
>> !llvm.module.flags = !{!0}
>> !llvm.ident = !{!1}
>>
>> !0 = !{i32 1, !"wchar_size", i32 4}
>> !1 = !{!"clang version 6.0.0 (git at github.com:llvm-mirror/clang.git
>> 0aed123216ad4a38a9c2b16f1783895fd5cb1a04)
>> (git at github.com:llvm-mirror/llvm.git
>> d209b37aec1e392dabbf9b5324ea4a60c36fbc55)"}
>>
>> $ /opt/llvm-svn/bin/opt -S -internalize -globaldce hello2.ll -o
>> hello2.dce.ll
>>
>> $ cat hello2.dce.ll
>> ; ModuleID = 'hello2.ll'
>> source_filename = "hello.c"
>> target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
>> target triple = "x86_64-unknown-linux-gnu"
>>
>> !llvm.module.flags = !{!0}
>> !llvm.ident = !{!1}
>>
>> !0 = !{i32 1, !"wchar_size", i32 4}
>> !1 = !{!"clang version 6.0.0 (git at github.com:llvm-mirror/clang.git
>> 0aed123216ad4a38a9c2b16f1783895fd5cb1a04)
>> (git at github.com:llvm-mirror/llvm.git
>> d209b37aec1e392dabbf9b5324ea4a60c36fbc55)"}
>>
>> $ /opt/llvm-svn/bin/lli hello2.dce.ll
>> 'main' function not found in module.
>>
>>
>> *No* more Alive Functions, so LLVM v6.0 Internalize and GlobalDCE
>> PASS failed to MarkLive Function together?
>>
>>
>> But LLVM 3.1 is able to work together:
>>
>> $ ./build/Release+Asserts/bin/opt --version
>> LLVM (http://llvm.org/):
>> LLVM version 3.1
>> Optimized build with assertions.
>> Built Oct 23 2017 (16:22:51).
>> Default target: x86_64-unknown-linux-gnu
>> Host CPU: corei7-avx
>>
>> $ ./build/Release+Asserts/bin/clang -S -emit-llvm hello.c -o hello0.ll
>>
>> $ cat hello0.ll
>> ; ModuleID = 'hello.c'
>> target datalayout =
>> "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
>> target triple = "x86_64-unknown-linux-gnu"
>>
>> @.str = private unnamed_addr constant [4 x i8] c"%d\0A\00", align 1
>>
>> define void @foo() nounwind uwtable {
>> entry:
>> ret void
>> }
>>
>> define i32 @main(i32 %argc, i8** %argv) nounwind uwtable {
>> entry:
>> %retval = alloca i32, align 4
>> %argc.addr = alloca i32, align 4
>> %argv.addr = alloca i8**, align 8
>> %i = alloca i32, align 4
>> store i32 0, i32* %retval
>> store i32 %argc, i32* %argc.addr, align 4
>> store i8** %argv, i8*** %argv.addr, align 8
>> store i32 0, i32* %i, align 4
>> br label %for.cond
>>
>> for.cond: ; preds = %for.inc,
>> %entry
>> %0 = load i32* %i, align 4
>> %cmp = icmp slt i32 %0, 10
>> br i1 %cmp, label %for.body, label %for.end
>>
>> for.body: ; preds = %for.cond
>> %1 = load i32* %i, align 4
>> %call = call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([4
>> x i8]* @.str, i32 0, i32 0), i32 %1)
>> br label %for.inc
>>
>> for.inc: ; preds = %for.body
>> %2 = load i32* %i, align 4
>> %inc = add nsw i32 %2, 1
>> store i32 %inc, i32* %i, align 4
>> br label %for.cond
>>
>> for.end: ; preds = %for.cond
>> ret i32 0
>> }
>>
>> declare i32 @printf(i8*, ...)
>>
>> $ ./build/Release+Asserts/bin/opt -S -internalize -globaldce
>> hello0.ll -o hello0.dce.ll
>>
>> $ cat hello0.dce.ll
>> ; ModuleID = 'hello0.ll'
>> target datalayout =
>> "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
>> target triple = "x86_64-unknown-linux-gnu"
>>
>> @.str = private unnamed_addr constant [4 x i8] c"%d\0A\00", align 1
>>
>> define i32 @main(i32 %argc, i8** %argv) nounwind uwtable {
>> entry:
>> %retval = alloca i32, align 4
>> %argc.addr = alloca i32, align 4
>> %argv.addr = alloca i8**, align 8
>> %i = alloca i32, align 4
>> store i32 0, i32* %retval
>> store i32 %argc, i32* %argc.addr, align 4
>> store i8** %argv, i8*** %argv.addr, align 8
>> store i32 0, i32* %i, align 4
>> br label %for.cond
>>
>> for.cond: ; preds = %for.inc,
>> %entry
>> %0 = load i32* %i, align 4
>> %cmp = icmp slt i32 %0, 10
>> br i1 %cmp, label %for.body, label %for.end
>>
>> for.body: ; preds = %for.cond
>> %1 = load i32* %i, align 4
>> %call = call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([4
>> x i8]* @.str, i32 0, i32 0), i32 %1)
>> br label %for.inc
>>
>> for.inc: ; preds = %for.body
>> %2 = load i32* %i, align 4
>> %inc = add nsw i32 %2, 1
>> store i32 %inc, i32* %i, align 4
>> br label %for.cond
>>
>> for.end: ; preds = %for.cond
>> ret i32 0
>> }
>>
>> declare i32 @printf(i8*, ...)
>>
>>
>> Succeeded drop DeadFunction foo.
>>
>> Maybe I wrongly use the Internalize and GlobalDCE PASS together?
>> please give me some hints, thanks a lot!
>>
>>
>> PS: LLVM 6.0 Internalize PASS is able to work, internal foo:
>>
>> $ /opt/llvm-svn/bin/opt -S -internalize hello2.ll -o hello2.internal.ll
>>
>> $ cat hello2.internal.ll
>> ; ModuleID = 'hello2.ll'
>> source_filename = "hello.c"
>> target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
>> target triple = "x86_64-unknown-linux-gnu"
>>
>> @.str = private unnamed_addr constant [4 x i8] c"%d\0A\00", align 1
>>
>> ; Function Attrs: noinline nounwind uwtable
>> define internal void @foo() #0 {
>> entry:
>> ret void
>> }
>>
>> ; Function Attrs: noinline nounwind uwtable
>> define internal i32 @main(i32 %argc, i8** %argv) #0 {
>> entry:
>> %retval = alloca i32, align 4
>> %argc.addr = alloca i32, align 4
>> %argv.addr = alloca i8**, align 8
>> %i = alloca i32, align 4
>> store i32 0, i32* %retval, align 4
>> store i32 %argc, i32* %argc.addr, align 4
>> store i8** %argv, i8*** %argv.addr, align 8
>> store i32 0, i32* %i, align 4
>> br label %for.cond
>>
>> for.cond: ; preds = %for.inc,
>> %entry
>> %0 = load i32, i32* %i, align 4
>> %cmp = icmp slt i32 %0, 10
>> br i1 %cmp, label %for.body, label %for.end
>>
>> for.body: ; preds = %for.cond
>> %1 = load i32, i32* %i, align 4
>> %call = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([4
>> x i8], [4 x i8]* @.str, i32 0, i32 0), i32 %1)
>> br label %for.inc
>>
>> for.inc: ; preds = %for.body
>> %2 = load i32, i32* %i, align 4
>> %inc = add nsw i32 %2, 1
>> store i32 %inc, i32* %i, align 4
>> br label %for.cond
>>
>> for.end: ; preds = %for.cond
>> ret i32 0
>> }
>>
>> declare i32 @printf(i8*, ...) #1
>>
>> attributes #0 = { noinline nounwind uwtable
>> "correctly-rounded-divide-sqrt-fp-math"="false"
>> "disable-tail-calls"="false" "less-precise-fpmad"="false"
>> "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf"
>> "no-infs-fp-math"="false" "no-jump-tables"="false"
>> "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false"
>> "no-trapping-math"="false" "stack-protector-buffer-size"="8"
>> "target-cpu"="x86-64" "target-features"="+fxsr,+mmx,+sse,+sse2,+x87"
>> "unsafe-fp-math"="false" "use-soft-float"="false" }
>> attributes #1 = { "correctly-rounded-divide-sqrt-fp-math"="false"
>> "disable-tail-calls"="false" "less-precise-fpmad"="false"
>> "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf"
>> "no-infs-fp-math"="false" "no-nans-fp-math"="false"
>> "no-signed-zeros-fp-math"="false" "no-trapping-math"="false"
>> "stack-protector-buffer-size"="8" "target-cpu"="x86-64"
>> "target-features"="+fxsr,+mmx,+sse,+sse2,+x87"
>> "unsafe-fp-math"="false" "use-soft-float"="false" }
>>
>> !llvm.module.flags = !{!0}
>> !llvm.ident = !{!1}
>>
>> !0 = !{i32 1, !"wchar_size", i32 4}
>> !1 = !{!"clang version 6.0.0 (git at github.com:llvm-mirror/clang.git
>> 0aed123216ad4a38a9c2b16f1783895fd5cb1a04)
>> (git at github.com:llvm-mirror/llvm.git
>> d209b37aec1e392dabbf9b5324ea4a60c36fbc55)"}
>>
>
--
Regards,
Leslie Zhai - https://reviews.llvm.org/p/xiangzhai/
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