[clang][driver][arm][macho] Default to -mframe-pointer=non-leaf. #154216
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@llvm/pr-subscribers-clang-driver @llvm/pr-subscribers-clang Author: Francesco Petrogalli (fpetrogalli) ChangesThe change in [1] uncovered a bug in the emission of the frame pointer. Specifically, before the fix in [1], non-leaf functions with a tail call were not emitting the frame pointer even if the default behavior emitted by clang was "frame-pointer=all". After the fix in [1], we had a set of internal build failures, caused by the fact that suddenly all non-leaf functions with tail calls started needing extra 4/8/16 bytes because of the extra push/pop instructions emitted to handle the frame pointer. Because of this, the size constraints we had on the firmware binaries were not met anymore. These projects are built with -Oz, therefore we have changed the default behavior of the Driver to emit -mframe-pointer=non-leaf when targeting anything that cares about size on MachO for armv7 (-Oz and -Os). The default behavior is also checked against An LLVM codegen test has also been added to make sure the test case we have in our firmware does not regress. [1] #109628 Full diff: https://github.com/llvm/llvm-project/pull/154216.diff 4 Files Affected:
diff --git a/clang/lib/Driver/ToolChains/CommonArgs.cpp b/clang/lib/Driver/ToolChains/CommonArgs.cpp
index eb88f7bd4b469..73f005b66bad4 100644
--- a/clang/lib/Driver/ToolChains/CommonArgs.cpp
+++ b/clang/lib/Driver/ToolChains/CommonArgs.cpp
@@ -151,11 +151,22 @@ static bool useFramePointerForTargetByDefault(const llvm::opt::ArgList &Args,
return true;
}
-static bool useLeafFramePointerForTargetByDefault(const llvm::Triple &Triple) {
+static bool
+useLeafFramePointerForTargetByDefault(const llvm::opt::ArgList &Args,
+ const llvm::Triple &Triple) {
if (Triple.isAArch64() || Triple.isPS() || Triple.isVE() ||
(Triple.isAndroid() && !Triple.isARM()))
return false;
+ if (Triple.isARM() && Triple.isOSBinFormatMachO()) {
+ if (Arg *A = Args.getLastArg(options::OPT_O_Group)) {
+ if (A->getOption().matches(options::OPT_O)) {
+ StringRef S(A->getValue());
+ if (S == "s" || S == "z")
+ return false;
+ }
+ }
+ }
return true;
}
@@ -252,7 +263,7 @@ getFramePointerKind(const llvm::opt::ArgList &Args,
clang::driver::options::OPT_fomit_frame_pointer, DefaultFP);
bool DefaultLeafFP =
- useLeafFramePointerForTargetByDefault(Triple) ||
+ useLeafFramePointerForTargetByDefault(Args, Triple) ||
(EnableFP && framePointerImpliesLeafFramePointer(Args, Triple));
bool EnableLeafFP = Args.hasFlag(
clang::driver::options::OPT_mno_omit_leaf_frame_pointer,
diff --git a/clang/test/Driver/frame-pointer-elim.c b/clang/test/Driver/frame-pointer-elim.c
index 6e21671f43775..c7206986a18ad 100644
--- a/clang/test/Driver/frame-pointer-elim.c
+++ b/clang/test/Driver/frame-pointer-elim.c
@@ -221,5 +221,31 @@
// RUN: %clang -### --target=aarch64-pc-windows-msvc -S -fomit-frame-pointer %s 2>&1 | \
// RUN: FileCheck --check-prefix=KEEP-RESERVED %s
+// At all optimization levels, -fno-omit-frame-pointer gives the default behavior.
+// RUN: %clang --target=armv7-apple-macho -### -S -Os %s -o %t.s -fno-omit-frame-pointer 2>&1 | FileCheck -check-prefix=KEEP-NON-LEAF %s
+// RUN: %clang --target=armv7-apple-macho -### -S -Oz %s -o %t.s -fno-omit-frame-pointer 2>&1 | FileCheck -check-prefix=KEEP-NON-LEAF %s
+// RUN: %clang --target=armv7-apple-macho -### -S -O0 %s -o %t.s -fno-omit-frame-pointer 2>&1 | FileCheck -check-prefix=KEEP-ALL %s
+// RUN: %clang --target=armv7-apple-macho -### -S -O1 %s -o %t.s -fno-omit-frame-pointer 2>&1 | FileCheck -check-prefix=KEEP-ALL %s
+// RUN: %clang --target=armv7-apple-macho -### -S -O2 %s -o %t.s -fno-omit-frame-pointer 2>&1 | FileCheck -check-prefix=KEEP-ALL %s
+// RUN: %clang --target=armv7-apple-macho -### -S -O3 %s -o %t.s -fno-omit-frame-pointer 2>&1 | FileCheck -check-prefix=KEEP-ALL %s
+
+// All all optimization levels, the frame pointer is "none" if -fomit-frame-pointer is specified.
+// RUN: %clang --target=armv7-apple-macho -### -S -Os %s -o %t.s -fomit-frame-pointer 2>&1 | FileCheck -check-prefix=KEEP-NONE %s
+// RUN: %clang --target=armv7-apple-macho -### -S -Oz %s -o %t.s -fomit-frame-pointer 2>&1 | FileCheck -check-prefix=KEEP-NONE %s
+// RUN: %clang --target=armv7-apple-macho -### -S -O0 %s -o %t.s -fomit-frame-pointer 2>&1 | FileCheck -check-prefix=KEEP-NONE %s
+// RUN: %clang --target=armv7-apple-macho -### -S -O3 %s -o %t.s -fomit-frame-pointer 2>&1 | FileCheck -check-prefix=KEEP-NONE %s
+// RUN: %clang --target=armv7-apple-macho -### -S -O1 %s -o %t.s -fomit-frame-pointer 2>&1 | FileCheck -check-prefix=KEEP-NONE %s
+// RUN: %clang --target=armv7-apple-macho -### -S -O2 %s -o %t.s -fomit-frame-pointer 2>&1 | FileCheck -check-prefix=KEEP-NONE %s
+
+// At -Oz/-Os, -fno-omit-frame-pointer + -mno-omit-leaf-frame-pointer give frame-pointer=all
+// RUN: %clang --target=armv7-apple-macho -### -S -Os %s -o %t.s -fno-omit-frame-pointer -mno-omit-leaf-frame-pointer 2>&1 | FileCheck -check-prefix=KEEP-ALL %s
+// RUN: %clang --target=armv7-apple-macho -### -S -Oz %s -o %t.s -fno-omit-frame-pointer -mno-omit-leaf-frame-pointer 2>&1 | FileCheck -check-prefix=KEEP-ALL %s
+
+// At -O0/1/2/3, -fomit-frame-pointer wins over -mno-omit-leaf-frame-pointer
+// RUN: %clang --target=armv7-apple-macho -### -S -O0 %s -o %t.s -fomit-frame-pointer -mno-omit-leaf-frame-pointer 2>&1 | FileCheck -check-prefix=KEEP-NONE %s
+// RUN: %clang --target=armv7-apple-macho -### -S -O3 %s -o %t.s -fomit-frame-pointer -mno-omit-leaf-frame-pointer 2>&1 | FileCheck -check-prefix=KEEP-NONE %s
+// RUN: %clang --target=armv7-apple-macho -### -S -O1 %s -o %t.s -fomit-frame-pointer -mno-omit-leaf-frame-pointer 2>&1 | FileCheck -check-prefix=KEEP-NONE %s
+// RUN: %clang --target=armv7-apple-macho -### -S -O2 %s -o %t.s -fomit-frame-pointer -mno-omit-leaf-frame-pointer 2>&1 | FileCheck -check-prefix=KEEP-NONE %s
+
void f0() {}
void f1() { f0(); }
diff --git a/clang/test/Driver/frame-pointer.c b/clang/test/Driver/frame-pointer.c
index 2015fa520c2a2..5a9eec5a9ae4a 100644
--- a/clang/test/Driver/frame-pointer.c
+++ b/clang/test/Driver/frame-pointer.c
@@ -80,12 +80,26 @@
// RUN: %clang --target=loongarch64 -### -S -O3 %s -o %t.s 2>&1 | FileCheck -check-prefix=CHECK3-64 %s
// RUN: %clang --target=loongarch64 -### -S -Os %s -o %t.s 2>&1 | FileCheck -check-prefix=CHECKs-64 %s
+// RUN: %clang --target=armv7-apple-macho -### -S -Os %s -o %t.s 2>&1 | FileCheck -check-prefix=CHECKs-32-MACHO %s
+// RUN: %clang --target=armv7-apple-macho -### -S -Oz %s -o %t.s 2>&1 | FileCheck -check-prefix=CHECKz-32-MACHO %s
+// RUN: %clang --target=armv7-apple-macho -### -S -O0 %s -o %t.s 2>&1 | FileCheck -check-prefix=CHECK0-32-MACHO %s
+// RUN: %clang --target=armv7-apple-macho -### -S -O1 %s -o %t.s 2>&1 | FileCheck -check-prefix=CHECK1-32-MACHO %s
+// RUN: %clang --target=armv7-apple-macho -### -S -O2 %s -o %t.s 2>&1 | FileCheck -check-prefix=CHECK2-32-MACHO %s
+// RUN: %clang --target=armv7-apple-macho -### -S -O3 %s -o %t.s 2>&1 | FileCheck -check-prefix=CHECK3-32-MACHO %s
+
// CHECK0-32: -mframe-pointer=all
// CHECK1-32-NOT: -mframe-pointer=all
// CHECK2-32-NOT: -mframe-pointer=all
// CHECK3-32-NOT: -mframe-pointer=all
// CHECKs-32-NOT: -mframe-pointer=all
+// CHECKs-32-MACHO: -mframe-pointer=non-leaf
+// CHECKz-32-MACHO: -mframe-pointer=non-leaf
+// CHECK0-32-MACHO: -mframe-pointer=all
+// CHECK1-32-MACHO: -mframe-pointer=all
+// CHECK2-32-MACHO: -mframe-pointer=all
+// CHECK3-32-MACHO: -mframe-pointer=all
+
// CHECK0-64: -mframe-pointer=all
// CHECK1-64-NOT: -mframe-pointer=all
// CHECK2-64-NOT: -mframe-pointer=all
diff --git a/llvm/test/CodeGen/ARM/macho-leaf-functions-fp.ll b/llvm/test/CodeGen/ARM/macho-leaf-functions-fp.ll
new file mode 100644
index 0000000000000..5bb19825a7655
--- /dev/null
+++ b/llvm/test/CodeGen/ARM/macho-leaf-functions-fp.ll
@@ -0,0 +1,31 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
+; RUN: llc < %s | FileCheck %s
+
+target triple = "thumbv7-apple-macho"
+
+define void @foo(ptr %0) "frame-pointer"="all" {
+; CHECK-LABEL: foo:
+; CHECK: @ %bb.0:
+; CHECK-NEXT: push {r7, lr}
+; CHECK-NEXT: mov r7, sp
+; CHECK-NEXT: ldrh r0, [r0]
+; CHECK-NEXT: pop.w {r7, lr}
+; CHECK-NEXT: b bar
+ %2 = load i16, ptr %0, align 2
+ tail call void @bar(i16 %2)
+ ret void
+}
+
+declare void @bar(i16) "frame-pointer"="all"
+
+define void @foo_02(ptr %0) "frame-pointer"="non-leaf" {
+; CHECK-LABEL: foo_02:
+; CHECK: @ %bb.0:
+; CHECK-NEXT: ldrh r0, [r0]
+; CHECK-NEXT: b bar_02
+ %2 = load i16, ptr %0, align 2
+ tail call void @bar_02(i16 %2)
+ ret void
+}
+
+declare void @bar_02(i16) "frame-pointer"="non-leaf"
|
|
@llvm/pr-subscribers-backend-arm Author: Francesco Petrogalli (fpetrogalli) ChangesThe change in [1] uncovered a bug in the emission of the frame pointer. Specifically, before the fix in [1], non-leaf functions with a tail call were not emitting the frame pointer even if the default behavior emitted by clang was "frame-pointer=all". After the fix in [1], we had a set of internal build failures, caused by the fact that suddenly all non-leaf functions with tail calls started needing extra 4/8/16 bytes because of the extra push/pop instructions emitted to handle the frame pointer. Because of this, the size constraints we had on the firmware binaries were not met anymore. These projects are built with -Oz, therefore we have changed the default behavior of the Driver to emit -mframe-pointer=non-leaf when targeting anything that cares about size on MachO for armv7 (-Oz and -Os). The default behavior is also checked against An LLVM codegen test has also been added to make sure the test case we have in our firmware does not regress. [1] #109628 Full diff: https://github.com/llvm/llvm-project/pull/154216.diff 4 Files Affected:
diff --git a/clang/lib/Driver/ToolChains/CommonArgs.cpp b/clang/lib/Driver/ToolChains/CommonArgs.cpp
index eb88f7bd4b469..73f005b66bad4 100644
--- a/clang/lib/Driver/ToolChains/CommonArgs.cpp
+++ b/clang/lib/Driver/ToolChains/CommonArgs.cpp
@@ -151,11 +151,22 @@ static bool useFramePointerForTargetByDefault(const llvm::opt::ArgList &Args,
return true;
}
-static bool useLeafFramePointerForTargetByDefault(const llvm::Triple &Triple) {
+static bool
+useLeafFramePointerForTargetByDefault(const llvm::opt::ArgList &Args,
+ const llvm::Triple &Triple) {
if (Triple.isAArch64() || Triple.isPS() || Triple.isVE() ||
(Triple.isAndroid() && !Triple.isARM()))
return false;
+ if (Triple.isARM() && Triple.isOSBinFormatMachO()) {
+ if (Arg *A = Args.getLastArg(options::OPT_O_Group)) {
+ if (A->getOption().matches(options::OPT_O)) {
+ StringRef S(A->getValue());
+ if (S == "s" || S == "z")
+ return false;
+ }
+ }
+ }
return true;
}
@@ -252,7 +263,7 @@ getFramePointerKind(const llvm::opt::ArgList &Args,
clang::driver::options::OPT_fomit_frame_pointer, DefaultFP);
bool DefaultLeafFP =
- useLeafFramePointerForTargetByDefault(Triple) ||
+ useLeafFramePointerForTargetByDefault(Args, Triple) ||
(EnableFP && framePointerImpliesLeafFramePointer(Args, Triple));
bool EnableLeafFP = Args.hasFlag(
clang::driver::options::OPT_mno_omit_leaf_frame_pointer,
diff --git a/clang/test/Driver/frame-pointer-elim.c b/clang/test/Driver/frame-pointer-elim.c
index 6e21671f43775..c7206986a18ad 100644
--- a/clang/test/Driver/frame-pointer-elim.c
+++ b/clang/test/Driver/frame-pointer-elim.c
@@ -221,5 +221,31 @@
// RUN: %clang -### --target=aarch64-pc-windows-msvc -S -fomit-frame-pointer %s 2>&1 | \
// RUN: FileCheck --check-prefix=KEEP-RESERVED %s
+// At all optimization levels, -fno-omit-frame-pointer gives the default behavior.
+// RUN: %clang --target=armv7-apple-macho -### -S -Os %s -o %t.s -fno-omit-frame-pointer 2>&1 | FileCheck -check-prefix=KEEP-NON-LEAF %s
+// RUN: %clang --target=armv7-apple-macho -### -S -Oz %s -o %t.s -fno-omit-frame-pointer 2>&1 | FileCheck -check-prefix=KEEP-NON-LEAF %s
+// RUN: %clang --target=armv7-apple-macho -### -S -O0 %s -o %t.s -fno-omit-frame-pointer 2>&1 | FileCheck -check-prefix=KEEP-ALL %s
+// RUN: %clang --target=armv7-apple-macho -### -S -O1 %s -o %t.s -fno-omit-frame-pointer 2>&1 | FileCheck -check-prefix=KEEP-ALL %s
+// RUN: %clang --target=armv7-apple-macho -### -S -O2 %s -o %t.s -fno-omit-frame-pointer 2>&1 | FileCheck -check-prefix=KEEP-ALL %s
+// RUN: %clang --target=armv7-apple-macho -### -S -O3 %s -o %t.s -fno-omit-frame-pointer 2>&1 | FileCheck -check-prefix=KEEP-ALL %s
+
+// All all optimization levels, the frame pointer is "none" if -fomit-frame-pointer is specified.
+// RUN: %clang --target=armv7-apple-macho -### -S -Os %s -o %t.s -fomit-frame-pointer 2>&1 | FileCheck -check-prefix=KEEP-NONE %s
+// RUN: %clang --target=armv7-apple-macho -### -S -Oz %s -o %t.s -fomit-frame-pointer 2>&1 | FileCheck -check-prefix=KEEP-NONE %s
+// RUN: %clang --target=armv7-apple-macho -### -S -O0 %s -o %t.s -fomit-frame-pointer 2>&1 | FileCheck -check-prefix=KEEP-NONE %s
+// RUN: %clang --target=armv7-apple-macho -### -S -O3 %s -o %t.s -fomit-frame-pointer 2>&1 | FileCheck -check-prefix=KEEP-NONE %s
+// RUN: %clang --target=armv7-apple-macho -### -S -O1 %s -o %t.s -fomit-frame-pointer 2>&1 | FileCheck -check-prefix=KEEP-NONE %s
+// RUN: %clang --target=armv7-apple-macho -### -S -O2 %s -o %t.s -fomit-frame-pointer 2>&1 | FileCheck -check-prefix=KEEP-NONE %s
+
+// At -Oz/-Os, -fno-omit-frame-pointer + -mno-omit-leaf-frame-pointer give frame-pointer=all
+// RUN: %clang --target=armv7-apple-macho -### -S -Os %s -o %t.s -fno-omit-frame-pointer -mno-omit-leaf-frame-pointer 2>&1 | FileCheck -check-prefix=KEEP-ALL %s
+// RUN: %clang --target=armv7-apple-macho -### -S -Oz %s -o %t.s -fno-omit-frame-pointer -mno-omit-leaf-frame-pointer 2>&1 | FileCheck -check-prefix=KEEP-ALL %s
+
+// At -O0/1/2/3, -fomit-frame-pointer wins over -mno-omit-leaf-frame-pointer
+// RUN: %clang --target=armv7-apple-macho -### -S -O0 %s -o %t.s -fomit-frame-pointer -mno-omit-leaf-frame-pointer 2>&1 | FileCheck -check-prefix=KEEP-NONE %s
+// RUN: %clang --target=armv7-apple-macho -### -S -O3 %s -o %t.s -fomit-frame-pointer -mno-omit-leaf-frame-pointer 2>&1 | FileCheck -check-prefix=KEEP-NONE %s
+// RUN: %clang --target=armv7-apple-macho -### -S -O1 %s -o %t.s -fomit-frame-pointer -mno-omit-leaf-frame-pointer 2>&1 | FileCheck -check-prefix=KEEP-NONE %s
+// RUN: %clang --target=armv7-apple-macho -### -S -O2 %s -o %t.s -fomit-frame-pointer -mno-omit-leaf-frame-pointer 2>&1 | FileCheck -check-prefix=KEEP-NONE %s
+
void f0() {}
void f1() { f0(); }
diff --git a/clang/test/Driver/frame-pointer.c b/clang/test/Driver/frame-pointer.c
index 2015fa520c2a2..5a9eec5a9ae4a 100644
--- a/clang/test/Driver/frame-pointer.c
+++ b/clang/test/Driver/frame-pointer.c
@@ -80,12 +80,26 @@
// RUN: %clang --target=loongarch64 -### -S -O3 %s -o %t.s 2>&1 | FileCheck -check-prefix=CHECK3-64 %s
// RUN: %clang --target=loongarch64 -### -S -Os %s -o %t.s 2>&1 | FileCheck -check-prefix=CHECKs-64 %s
+// RUN: %clang --target=armv7-apple-macho -### -S -Os %s -o %t.s 2>&1 | FileCheck -check-prefix=CHECKs-32-MACHO %s
+// RUN: %clang --target=armv7-apple-macho -### -S -Oz %s -o %t.s 2>&1 | FileCheck -check-prefix=CHECKz-32-MACHO %s
+// RUN: %clang --target=armv7-apple-macho -### -S -O0 %s -o %t.s 2>&1 | FileCheck -check-prefix=CHECK0-32-MACHO %s
+// RUN: %clang --target=armv7-apple-macho -### -S -O1 %s -o %t.s 2>&1 | FileCheck -check-prefix=CHECK1-32-MACHO %s
+// RUN: %clang --target=armv7-apple-macho -### -S -O2 %s -o %t.s 2>&1 | FileCheck -check-prefix=CHECK2-32-MACHO %s
+// RUN: %clang --target=armv7-apple-macho -### -S -O3 %s -o %t.s 2>&1 | FileCheck -check-prefix=CHECK3-32-MACHO %s
+
// CHECK0-32: -mframe-pointer=all
// CHECK1-32-NOT: -mframe-pointer=all
// CHECK2-32-NOT: -mframe-pointer=all
// CHECK3-32-NOT: -mframe-pointer=all
// CHECKs-32-NOT: -mframe-pointer=all
+// CHECKs-32-MACHO: -mframe-pointer=non-leaf
+// CHECKz-32-MACHO: -mframe-pointer=non-leaf
+// CHECK0-32-MACHO: -mframe-pointer=all
+// CHECK1-32-MACHO: -mframe-pointer=all
+// CHECK2-32-MACHO: -mframe-pointer=all
+// CHECK3-32-MACHO: -mframe-pointer=all
+
// CHECK0-64: -mframe-pointer=all
// CHECK1-64-NOT: -mframe-pointer=all
// CHECK2-64-NOT: -mframe-pointer=all
diff --git a/llvm/test/CodeGen/ARM/macho-leaf-functions-fp.ll b/llvm/test/CodeGen/ARM/macho-leaf-functions-fp.ll
new file mode 100644
index 0000000000000..5bb19825a7655
--- /dev/null
+++ b/llvm/test/CodeGen/ARM/macho-leaf-functions-fp.ll
@@ -0,0 +1,31 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
+; RUN: llc < %s | FileCheck %s
+
+target triple = "thumbv7-apple-macho"
+
+define void @foo(ptr %0) "frame-pointer"="all" {
+; CHECK-LABEL: foo:
+; CHECK: @ %bb.0:
+; CHECK-NEXT: push {r7, lr}
+; CHECK-NEXT: mov r7, sp
+; CHECK-NEXT: ldrh r0, [r0]
+; CHECK-NEXT: pop.w {r7, lr}
+; CHECK-NEXT: b bar
+ %2 = load i16, ptr %0, align 2
+ tail call void @bar(i16 %2)
+ ret void
+}
+
+declare void @bar(i16) "frame-pointer"="all"
+
+define void @foo_02(ptr %0) "frame-pointer"="non-leaf" {
+; CHECK-LABEL: foo_02:
+; CHECK: @ %bb.0:
+; CHECK-NEXT: ldrh r0, [r0]
+; CHECK-NEXT: b bar_02
+ %2 = load i16, ptr %0, align 2
+ tail call void @bar_02(i16 %2)
+ ret void
+}
+
+declare void @bar_02(i16) "frame-pointer"="non-leaf"
|
jroelofs
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The commit in [1] changes the behavior of the Arm backend for the attribute frame-pointer=all. Before [1], leaf functions marked with frame-pointer=all were not emitting the frame-pointer. After [1], frame-pointer=all started generating frame pointer for all functions, including leaf functions. However, the default behavior for the driver in clang is to emit the command line option `-mframe-pointer=all` on Arm, if no options for handling the frame pointer is specified at command line. This causes observable regressions. This patch addresses these regressions by configuring the driver so to emit `-mframe-pointer=non-leaf` when targeting Arm. Codegen tests dealing with frame pointer generation have been extended to handle functions with a tail call, since this configuration was missing. [1] 4a2bd78
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[clang][driver][arm][macho] Default to -mframe-pointer=non-leaf.
The commit in [1] changes the behavior of the Arm backend for the
attribute frame-pointer=all. Before [1], leaf functions marked with
frame-pointer=all were not emitting the frame-pointer.
After [1], frame-pointer=all started generating frame pointer for all
functions, including leaf functions.
However, the default behavior for the driver in clang is to emit the
command line option
-mframe-pointer=allon Arm, if no options forhandling the frame pointer is specified at command line. This causes
observable regressions.
This patch addresses these regressions by configuring the driver so
to emit
-mframe-pointer=non-leafwhen targeting Arm.Codegen tests dealing with frame pointer generation have been extended
to handle functions with a tail call, since this configuration was
missing.
[1] 4a2bd78f5b0d0661c23dff9c4b93a393a49dbf9aWIP