libdrgn: use if instead of switch for dw_foo_str

Some constant types (e.g. DW_OP) have duplicate values for vendor specific extensions, so generating the dw_foo_str function for them results in "duplicate case value" compiler errors. Use if statements instead and use the first match. This doesn't change code generated for dw_tag_str with either GCC or Clang. Signed-off-by: Omar Sandoval <[email protected]>
Asphaltt · Oct 4, 2023 · 2fd4af2 · 2fd4af2
1 parent 659c446
commit 2fd4af2
Show file tree

Hide file tree

Showing 2 changed files with 6 additions and 12 deletions.
diff --git a/libdrgn/dwarf_constants.c b/libdrgn/dwarf_constants.c
@@ -6,16 +6,13 @@
 
 #include "dwarf_constants.h"
 
-#define X(name, value) case name: return #name;
+#define X(name, _) if (value == name) return #name;
 
 const char *dw_tag_str(int value, char buf[static DW_TAG_STR_BUF_LEN])
 {
-	switch (value) {
 	DW_TAG_DEFINITIONS
-	default:
-		snprintf(buf, DW_TAG_STR_BUF_LEN, DW_TAG_STR_UNKNOWN_FORMAT, value);
-		return buf;
-	}
+	snprintf(buf, DW_TAG_STR_BUF_LEN, DW_TAG_STR_UNKNOWN_FORMAT, value);
+	return buf;
 }
 
 #undef X
diff --git a/scripts/gen_dwarf_constants.py b/scripts/gen_dwarf_constants.py
@@ -202,7 +202,7 @@ def gen_dwarf_constants_c(
 
 #include "dwarf_constants.h"
 
-#define X(name, value) case name: return #name;
+#define X(name, _) if (value == name) return #name;
 """
     )
     for constant_type in dwarf_constants:
@@ -211,12 +211,9 @@ def gen_dwarf_constants_c(
                 f"""
 const char *{constant_type.name.lower()}_str(int value, char buf[static {constant_type.name}_STR_BUF_LEN])
 {{
-	switch (value) {{
 	{constant_type.name}_DEFINITIONS
-	default:
-		snprintf(buf, {constant_type.name}_STR_BUF_LEN, {constant_type.name}_STR_UNKNOWN_FORMAT, value);
-		return buf;
-	}}
+	snprintf(buf, {constant_type.name}_STR_BUF_LEN, {constant_type.name}_STR_UNKNOWN_FORMAT, value);
+	return buf;
 }}
 """
             )