[clang] 6bf6730 - [clang] fix generation of .debug_aranges with LTO

[David Blaikie via cfe-commits]

Author: Azat Khuzhin
Date: 2022-09-13T22:33:56Z
New Revision: 6bf6730ac55e064edf46915ebba02e9c716f48e8

URL: https://github.com/llvm/llvm-project/commit/6bf6730ac55e064edf46915ebba02e9c716f48e8
DIFF: https://github.com/llvm/llvm-project/commit/6bf6730ac55e064edf46915ebba02e9c716f48e8.diff

LOG: [clang] fix generation of .debug_aranges with LTO

Right now in case of LTO the section is not emited:

    $ cat test.c
    void __attribute__((optnone)) bar()
    {
    }
    void __attribute__((optnone)) foo()
    {
            bar();
    }
    int main()
    {
            foo();
    }

    $ clang -flto=thin -gdwarf-aranges -g -O3 test.c
    $ eu-readelf -waranges a.out  | fgrep -c -e foo -e bar
    0

    $ clang -gdwarf-aranges -g -O3 test.c
    $ eu-readelf -waranges a.out  | fgrep -c -e foo -e bar
    2

Fix this by passing explicitly -mllvm -generate-arange-section.

P.S. although this looks like a hack, since none of -mllvm was passed to
the lld before.

Signed-off-by: Azat Khuzhin <a.khuzhin at semrush.com>
Suggested-by: OCHyams <orlando.hyams at sony.com>

Reviewed By: dblaikie

Differential Revision: https://reviews.llvm.org/D133092

Added: 
    

Modified: 
    clang/lib/Driver/ToolChains/CommonArgs.cpp
    clang/test/Driver/debug-options.c

Removed: 
    


################################################################################
diff  --git a/clang/lib/Driver/ToolChains/CommonArgs.cpp b/clang/lib/Driver/ToolChains/CommonArgs.cpp
index 22025d95e7c8f..c61fcfc946b89 100644
--- a/clang/lib/Driver/ToolChains/CommonArgs.cpp
+++ b/clang/lib/Driver/ToolChains/CommonArgs.cpp
@@ -506,6 +506,19 @@ void tools::addLTOOptions(const ToolChain &ToolChain, const ArgList &Args,
             Suffix,
         Plugin);
     CmdArgs.push_back(Args.MakeArgString(Plugin));
+  } else {
+    // NOTE:
+    // - it is not possible to use lld for PS4
+    // - addLTOOptions() is not used for PS5
+    // Hence no need to handle SCE (like in Clang.cpp::renderDebugOptions()).
+    //
+    // But note, this solution is far from perfect, better to encode it into IR
+    // metadata, but this may not be worth it, since it looks like aranges is
+    // on the way out.
+    if (Args.hasArg(options::OPT_gdwarf_aranges)) {
+      CmdArgs.push_back(Args.MakeArgString("-mllvm"));
+      CmdArgs.push_back(Args.MakeArgString("-generate-arange-section"));
+    }
   }
 
   // Try to pass driver level flags relevant to LTO code generation down to

diff  --git a/clang/test/Driver/debug-options.c b/clang/test/Driver/debug-options.c
index 04004716aa501..2da192d098e24 100644
--- a/clang/test/Driver/debug-options.c
+++ b/clang/test/Driver/debug-options.c
@@ -246,7 +246,11 @@
 // RUN: %clang -### -c -glldb %s 2>&1 | FileCheck -check-prefix=NOPUB %s
 // RUN: %clang -### -c -glldb -gno-pubnames %s 2>&1 | FileCheck -check-prefix=NOPUB %s
 //
-// RUN: %clang -### -c -gdwarf-aranges %s 2>&1 | FileCheck -check-prefix=GARANGE %s
+// RUN: %clang -### -target x86_64-unknown-linux -c -gdwarf-aranges %s 2>&1 | FileCheck -check-prefix=GARANGE %s
+// RUN: %clang -### -target x86_64-unknown-linux -flto -gdwarf-aranges %s 2>&1 | FileCheck -check-prefix=LDGARANGE %s
+// RUN: %clang -### -target x86_64-unknown-linux -flto=thin -gdwarf-aranges %s 2>&1 | FileCheck -check-prefix=LDGARANGE %s
+// RUN: %clang -### -target x86_64-unknown-linux -fuse-ld=lld -flto -gdwarf-aranges %s 2>&1 | FileCheck -check-prefix=LLDGARANGE %s
+// RUN: %clang -### -target x86_64-unknown-linux -fuse-ld=lld -flto=thin -gdwarf-aranges %s 2>&1 | FileCheck -check-prefix=LLDGARANGE %s
 //
 // RUN: %clang -### -fdebug-types-section -target x86_64-unknown-linux %s 2>&1 \
 // RUN:        | FileCheck -check-prefix=FDTS %s
@@ -371,6 +375,8 @@
 // NORNGBSE-NOT: -fdebug-ranges-base-address
 //
 // GARANGE-DAG: -generate-arange-section
+// LDGARANGE-NOT: {{".*lld.*"}} {{.*}} "-generate-arange-section"
+// LLDGARANGE: {{".*lld.*"}} {{.*}} "-generate-arange-section"
 //
 // FDTS: "-mllvm" "-generate-type-units"
 // FDTSE: error: unsupported option '-fdebug-types-section' for target 'x86_64-apple-darwin'