Disable PIC/PIE for MSP430 target

[dmikushin]

Summary

Relocatable code generation is meaningless on MSP430, as the platform is too small to use shared libraries.

[grimar]

Can it be tested with a test case?

[dmikushin]

Adding test case

[asl]

The patch was reverted – the test requires fully configured msp430 configuration and therefore was breaking the bots.

[asl]

Please make sure the test passes.

[dmikushin]

Unbreaking patch by providing an appropriate toolchain requirement

[grimar]

What I noticed, this seems to introduce the first test case in test\CodeGen\MSP430 folder which uses clang. All the others use llc. Is it OK?

[grimar]

Oh sorry, I looked in the wrong folder, my previous comment was not correct.

So, this patch adds a test to test\CodeGen when we have test\CodeGen\MSP430 folder.
And test\CodeGen does not have any tests now at all.
So I guess the correct way would probably be:

1. To move the test to test\CodeGen\MSP430 folder.
2. To make it use 'llc`.

[grimar]

Ok, please ignore my comments above. I applied the patch and found it creates the test in llvm\tools\clang\test\CodeGen and not in llvm\test\CodeGen. Was confused by phab, sorry for the noise.

lib/Driver/ToolChains/MSP430.h

                              llvm::opt::ArgStringList &CC1Args,
                              Action::OffloadKind) const override;
 
+  bool isPICDefault() const override { return false; }
+  bool isPIEDefault() const override { return false; }
+  bool isPICDefaultForced() const override { return true; }
+
 protected:
   Tool *buildLinker() const override;
 

test/CodeGen/msp430-reloc.c

+// RUN: %clang -target msp430 -fPIC -S %s -o - | FileCheck %s
+
+// Check the compilation does not crash as it was crashing before with "-fPIC" enabled
+
+void *alloca(unsigned int size);
+
+// CHECK: .globl foo
+short foo(char** data, char encoding)
+{
+  char* encoding_addr = alloca(sizeof(char));
+  *encoding_addr = encoding;
+
+  char tmp3 = *encoding_addr;
+  short conv2 = tmp3;
+  short and = conv2 & 0xf;
+
+  switch (and)
+  {
+  case 0 :
+  case 4 :
+  case 10 :
+    return 1;
+  case 11 :
+    return 2;
+  }
+
+  return 0;
+}
+