Revert "Revert "[PowerPC][ELFv2ABI] Allocate parameter area on-demand to reduce stack frame size""

After inspection, it's an UB in our code base. Someone cast a var-arg
function pointer to a non-var-arg one. :/

Re-commit r296771 to continue testing on the patch.

Sorry for the trouble!

llvm-svn: 297256

1 files changed, 86 insertions, 0 deletions

diff --git a/llvm/test/CodeGen/PowerPC/stacksize.ll b/llvm/test/CodeGen/PowerPC/stacksize.ll
new file mode 100644
index 00000000000..947aaa0fa49
--- /dev/null
+++ b/llvm/test/CodeGen/PowerPC/stacksize.ll
@@ -0,0 +1,86 @@
+; For ELFv2 ABI, we can avoid allocating the parameter area in the stack frame of the caller function
+; if all the arguments can be passed to the callee in registers.
+; For ELFv1 ABI, we always need to allocate the parameter area.
+
+; Tests for ELFv2 ABI
+; RUN: llc -verify-machineinstrs -mtriple=powerpc64le-unknown-linux-gnu -target-abi elfv2 < %s | FileCheck %s -check-prefix=PPC64-ELFV2
+; RUN: llc -verify-machineinstrs -mtriple=powerpc64-unknown-linux-gnu -target-abi elfv2 < %s | FileCheck %s -check-prefix=PPC64-ELFV2
+
+; Tests for ELFv1 ABI
+; RUN: llc -verify-machineinstrs -mtriple=powerpc64le-unknown-linux-gnu -target-abi elfv1 < %s | FileCheck %s -check-prefix=PPC64-ELFV1
+; RUN: llc -verify-machineinstrs -mtriple=powerpc64-unknown-linux-gnu -target-abi elfv1 < %s | FileCheck %s -check-prefix=PPC64-ELFV1
+
+; If the callee has at most eight integer args, parameter area can be ommited for ELFv2 ABI.
+
+; PPC64-ELFV2-LABEL: WithoutParamArea1:
+; PPC64-ELFV2-NOT: stw {{[0-9]+}}, -{{[0-9]+}}(1)
+; PPC64-ELFV2: stdu 1, -32(1)
+; PPC64-ELFV2: addi 1, 1, 32
+; PPC64-ELFV2-NOT: lwz {{[0-9]+}}, -{{[0-9]+}}(1)
+; PPC64-ELFV1-LABEL: WithoutParamArea1:
+; PPC64-ELFV1-NOT: stw {{[0-9]+}}, -{{[0-9]+}}(1)
+; PPC64-ELFV1: stdu 1, -112(1)
+; PPC64-ELFV1: addi 1, 1, 112
+; PPC64-ELFV1-NOT: lwz {{[0-9]+}}, -{{[0-9]+}}(1)
+define signext i32 @WithoutParamArea1(i32 signext %a) local_unnamed_addr #0 {
+entry:
+  %call = tail call signext i32 @onearg(i32 signext %a) #2
+  ret i32 %call
+}
+
+; PPC64-ELFV2-LABEL: WithoutParamArea2:
+; PPC64-ELFV2-NOT: stw {{[0-9]+}}, -{{[0-9]+}}(1)
+; PPC64-ELFV2: stdu 1, -32(1)
+; PPC64-ELFV2: addi 1, 1, 32
+; PPC64-ELFV2-NOT: lwz {{[0-9]+}}, -{{[0-9]+}}(1)
+; PPC64-ELFV1-LABEL: WithoutParamArea2:
+; PPC64-ELFV1-NOT: stw {{[0-9]+}}, -{{[0-9]+}}(1)
+; PPC64-ELFV1: stdu 1, -112(1)
+; PPC64-ELFV1: addi 1, 1, 112
+; PPC64-ELFV1-NOT: lwz {{[0-9]+}}, -{{[0-9]+}}(1)
+define signext i32 @WithoutParamArea2(i32 signext %a) local_unnamed_addr #0 {
+entry:
+  %call = tail call signext i32 @eightargs(i32 signext %a, i32 signext %a, i32 signext %a, i32 signext %a, i32 signext %a, i32 signext %a, i32 signext %a, i32 signext %a) #2
+  ret i32 %call
+}
+
+; If the callee has more than eight integer args or variable number of args, 
+; parameter area cannot be ommited even for ELFv2 ABI
+
+; PPC64-ELFV2-LABEL: WithParamArea1:
+; PPC64-ELFV2-NOT: stw {{[0-9]+}}, -{{[0-9]+}}(1)
+; PPC64-ELFV2: stdu 1, -96(1)
+; PPC64-ELFV2: addi 1, 1, 96
+; PPC64-ELFV2-NOT: lwz {{[0-9]+}}, -{{[0-9]+}}(1)
+; PPC64-ELFV1-LABEL: WithParamArea1:
+; PPC64-ELFV1-NOT: stw {{[0-9]+}}, -{{[0-9]+}}(1)
+; PPC64-ELFV1: stdu 1, -112(1)
+; PPC64-ELFV1: addi 1, 1, 112
+; PPC64-ELFV1-NOT: lwz {{[0-9]+}}, -{{[0-9]+}}(1)
+define signext i32 @WithParamArea1(i32 signext %a) local_unnamed_addr #0 {
+entry:
+  %call = tail call signext i32 (i32, ...) @varargs(i32 signext %a, i32 signext %a) #2
+  ret i32 %call
+}
+
+; PPC64-ELFV2-LABEL: WithParamArea2:
+; PPC64-ELFV2-NOT: stw {{[0-9]+}}, -{{[0-9]+}}(1)
+; PPC64-ELFV2: stdu 1, -112(1)
+; PPC64-ELFV2: addi 1, 1, 112
+; PPC64-ELFV2-NOT: lwz {{[0-9]+}}, -{{[0-9]+}}(1)
+; PPC64-ELFV1-LABEL: WithParamArea2:
+; PPC64-ELFV1-NOT: stw {{[0-9]+}}, -{{[0-9]+}}(1)
+; PPC64-ELFV1: stdu 1, -128(1)
+; PPC64-ELFV1: addi 1, 1, 128
+; PPC64-ELFV1-NOT: lwz {{[0-9]+}}, -{{[0-9]+}}(1)
+define signext i32 @WithParamArea2(i32 signext %a) local_unnamed_addr #0 {
+entry:
+  %call = tail call signext i32 @nineargs(i32 signext %a, i32 signext %a, i32 signext %a, i32 signext %a, i32 signext %a, i32 signext %a, i32 signext %a, i32 signext %a, i32 signext %a) #2
+  ret i32 %call
+}
+
+declare signext i32 @onearg(i32 signext) local_unnamed_addr #1
+declare signext i32 @eightargs(i32 signext, i32 signext, i32 signext, i32 signext, i32 signext, i32 signext, i32 signext, i32 signext) local_unnamed_addr #1
+declare signext i32 @nineargs(i32 signext, i32 signext, i32 signext, i32 signext, i32 signext, i32 signext, i32 signext, i32 signext, i32 signext) local_unnamed_addr #1
+declare signext i32 @varargs(i32 signext, ...) local_unnamed_addr #1
+