[DebugInfo] Introduce DW_OP_LLVM_convert

Introduce a DW_OP_LLVM_convert Dwarf expression pseudo op that allows
for a convenient way to perform type conversions on the Dwarf expression
stack. As an additional bonus it paves the way for using other Dwarf
v5 ops that need to reference a base_type.

The new DW_OP_LLVM_convert is used from lib/Transforms/Utils/Local.cpp
to perform sext/zext on debug values but mainly the patch is about
preparing terrain for adding other Dwarf v5 ops that need to reference a
base_type.

For Dwarf v5 the op maps to DW_OP_convert and for earlier versions a
complex shift & mask pattern is generated to emulate sext/zext.

This is a recommit of r356442 with trivial fixes for the failing tests.

Differential Revision: https://reviews.llvm.org/D56587

llvm-svn: 356451

1 files changed, 22 insertions, 18 deletions

diff --git a/llvm/unittests/Transforms/Utils/LocalTest.cpp b/llvm/unittests/Transforms/Utils/LocalTest.cpp
index 80f263d24a7..f83e10af756 100644
--- a/llvm/unittests/Transforms/Utils/LocalTest.cpp
+++ b/llvm/unittests/Transforms/Utils/LocalTest.cpp
@@ -788,31 +788,35 @@ TEST(Local, ReplaceAllDbgUsesWith) {
   };
 
   // Case 1: The original expr is empty, so no deref is needed.
-  EXPECT_TRUE(hasADbgVal({DW_OP_dup, DW_OP_constu, 31, DW_OP_shr, DW_OP_lit0,
-                          DW_OP_not, DW_OP_mul, DW_OP_or, DW_OP_stack_value}));
+  EXPECT_TRUE(hasADbgVal({DW_OP_LLVM_convert, 32, DW_ATE_signed,
+                         DW_OP_LLVM_convert, 64, DW_ATE_signed,
+                         DW_OP_stack_value}));
 
   // Case 2: Perform an address calculation with the original expr, deref it,
   // then sign-extend the result.
-  EXPECT_TRUE(hasADbgVal({DW_OP_lit0, DW_OP_mul, DW_OP_deref, DW_OP_dup,
-                          DW_OP_constu, 31, DW_OP_shr, DW_OP_lit0, DW_OP_not,
-                          DW_OP_mul, DW_OP_or, DW_OP_stack_value}));
+  EXPECT_TRUE(hasADbgVal({DW_OP_lit0, DW_OP_mul, DW_OP_deref,
+                         DW_OP_LLVM_convert, 32, DW_ATE_signed,
+                         DW_OP_LLVM_convert, 64, DW_ATE_signed,
+                         DW_OP_stack_value}));
 
   // Case 3: Insert the sign-extension logic before the DW_OP_stack_value.
-  EXPECT_TRUE(hasADbgVal({DW_OP_lit0, DW_OP_mul, DW_OP_dup, DW_OP_constu, 31,
-                          DW_OP_shr, DW_OP_lit0, DW_OP_not, DW_OP_mul, DW_OP_or,
-                          DW_OP_stack_value}));
+  EXPECT_TRUE(hasADbgVal({DW_OP_lit0, DW_OP_mul, DW_OP_LLVM_convert, 32,
+                         DW_ATE_signed, DW_OP_LLVM_convert, 64, DW_ATE_signed,
+                         DW_OP_stack_value}));
 
   // Cases 4-6: Just like cases 1-3, but preserve the fragment at the end.
-  EXPECT_TRUE(hasADbgVal({DW_OP_dup, DW_OP_constu, 31, DW_OP_shr, DW_OP_lit0,
-                          DW_OP_not, DW_OP_mul, DW_OP_or, DW_OP_stack_value,
-                          DW_OP_LLVM_fragment, 0, 8}));
-  EXPECT_TRUE(
-      hasADbgVal({DW_OP_lit0, DW_OP_mul, DW_OP_deref, DW_OP_dup, DW_OP_constu,
-                  31, DW_OP_shr, DW_OP_lit0, DW_OP_not, DW_OP_mul, DW_OP_or,
-                  DW_OP_stack_value, DW_OP_LLVM_fragment, 0, 8}));
-  EXPECT_TRUE(hasADbgVal({DW_OP_lit0, DW_OP_mul, DW_OP_dup, DW_OP_constu, 31,
-                          DW_OP_shr, DW_OP_lit0, DW_OP_not, DW_OP_mul, DW_OP_or,
-                          DW_OP_stack_value, DW_OP_LLVM_fragment, 0, 8}));
+  EXPECT_TRUE(hasADbgVal({DW_OP_LLVM_convert, 32, DW_ATE_signed,
+                         DW_OP_LLVM_convert, 64, DW_ATE_signed,
+                         DW_OP_stack_value, DW_OP_LLVM_fragment, 0, 8}));
+
+  EXPECT_TRUE(hasADbgVal({DW_OP_lit0, DW_OP_mul, DW_OP_deref,
+                         DW_OP_LLVM_convert, 32, DW_ATE_signed,
+                         DW_OP_LLVM_convert, 64, DW_ATE_signed,
+                         DW_OP_stack_value, DW_OP_LLVM_fragment, 0, 8}));
+
+  EXPECT_TRUE(hasADbgVal({DW_OP_lit0, DW_OP_mul, DW_OP_LLVM_convert, 32,
+                         DW_ATE_signed, DW_OP_LLVM_convert, 64, DW_ATE_signed,
+                         DW_OP_stack_value, DW_OP_LLVM_fragment, 0, 8}));
 
   verifyModule(*M, &errs(), &BrokenDebugInfo);
   ASSERT_FALSE(BrokenDebugInfo);