From aa5514fcf2305233c468b358d22ab171f377aef9 Mon Sep 17 00:00:00 2001
From: riverbl <94326797+riverbl@users.noreply.github.com>
Date: Fri, 14 Jan 2022 23:11:20 +0000
Subject: [PATCH] translate-c: Fix issues translating macro define of hex float
 constant

* Fix incorrect result when the first digit after the decimal point is not 0-9 - eg 0x0.ap0
* Fix compiler panic when the number starts with `0X` with a capital `X` - eg 0X0p0
* Fix compiler panic when the number has a decimal point immediately after `0x` - eg 0x.0p0
---
 src/translate_c.zig  | 20 +++++++++++++++++++-
 test/translate_c.zig | 16 ++++++++++++++++
 2 files changed, 35 insertions(+), 1 deletion(-)

diff --git a/src/translate_c.zig b/src/translate_c.zig
index 668d6c7cc4..b8f5116a75 100644
--- a/src/translate_c.zig
+++ b/src/translate_c.zig
@@ -5603,7 +5603,25 @@ fn parseCNumLit(c: *Context, m: *MacroCtx) ParseError!Node {
         .FloatLiteral => |suffix| {
             if (suffix != .none) lit_bytes = lit_bytes[0 .. lit_bytes.len - 1];
 
-            if (mem.indexOfScalar(u8, lit_bytes, '.')) |dot_index| {
+            if (lit_bytes.len >= 2 and std.ascii.eqlIgnoreCase(lit_bytes[0..2], "0x")) {
+                if (mem.indexOfScalar(u8, lit_bytes, '.')) |dot_index| {
+                    if (dot_index == 2) {
+                        lit_bytes = try std.fmt.allocPrint(c.arena, "0x0{s}", .{lit_bytes[2..]});
+                    } else if (dot_index + 1 == lit_bytes.len or !std.ascii.isXDigit(lit_bytes[dot_index + 1])) {
+                        // If the literal lacks a digit after the `.`, we need to
+                        // add one since `0x1.p10` would be invalid syntax in Zig.
+                        lit_bytes = try std.fmt.allocPrint(c.arena, "0x{s}0{s}", .{
+                            lit_bytes[2 .. dot_index + 1],
+                            lit_bytes[dot_index + 1 ..],
+                        });
+                    }
+                }
+
+                if (lit_bytes[1] == 'X') {
+                    // Hexadecimal with capital X, valid in C but not in Zig
+                    lit_bytes = try std.fmt.allocPrint(c.arena, "0x{s}", .{lit_bytes[2..]});
+                }
+            } else if (mem.indexOfScalar(u8, lit_bytes, '.')) |dot_index| {
                 if (dot_index == 0) {
                     lit_bytes = try std.fmt.allocPrint(c.arena, "0{s}", .{lit_bytes});
                 } else if (dot_index + 1 == lit_bytes.len or !std.ascii.isDigit(lit_bytes[dot_index + 1])) {
diff --git a/test/translate_c.zig b/test/translate_c.zig
index dc559c126c..bd83f8034b 100644
--- a/test/translate_c.zig
+++ b/test/translate_c.zig
@@ -1137,6 +1137,7 @@ pub fn addCases(cases: *tests.TranslateCContext) void {
         \\#define BAR .12345
         \\#define baz 1e1
         \\#define BAZ 42e-3f
+        \\#define foobar -73.L
     , &[_][]const u8{
         "pub const foo = @as(f32, 3.14);",
         "pub const bar = @as(c_longdouble, 16.0e-2);",
@@ -1144,6 +1145,21 @@ pub fn addCases(cases: *tests.TranslateCContext) void {
         "pub const BAR = 0.12345;",
         "pub const baz = 1e1;",
         "pub const BAZ = @as(f32, 42e-3);",
+        "pub const foobar = -@as(c_longdouble, 73.0);",
+    });
+
+    cases.add("macro defines hexadecimal float",
+        \\#define FOO 0xf7p38
+        \\#define BAR -0X8F.BP5F
+        \\#define FOOBAR 0X0P+0
+        \\#define BAZ -0x.0a5dp+12
+        \\#define FOOBAZ 0xfE.P-1l
+    , &[_][]const u8{
+        "pub const FOO = 0xf7p38;",
+        "pub const BAR = -@as(f32, 0x8F.BP5);",
+        "pub const FOOBAR = 0x0P+0;",
+        "pub const BAZ = -0x0.0a5dp+12;",
+        "pub const FOOBAZ = @as(c_longdouble, 0xfE.0P-1);",
     });
 
     cases.add("comments",