From 82dfd1d03f629a45de59135640ae84f9c94bdaf9 Mon Sep 17 00:00:00 2001
From: Paho Lurie-Gregg <paho@amazon.com>
Date: Thu, 25 Mar 2021 22:13:13 -0700
Subject: [PATCH] Support rustflags from cargo config

Cargo will ignore any rustflags set in a config file if `RUSTFLAGS` is
set. Because cargo-fuzz always sets `RUSTFLAGS`, flags in config files
are always ignored.

So, instead of just pulling prior flags from `RUSTFLAGS`, we can rely on
cargo to find them for us.
---
 CHANGELOG.md   |   2 +-
 Cargo.lock     | 768 ++++++++++++++++++++++++++++++++++++++++++++++++-
 Cargo.toml     |   1 +
 src/project.rs |  19 +-
 4 files changed, 785 insertions(+), 5 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8a63248..8ab9831 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,7 +4,7 @@ Released YYYY-MM-DD.
 
 ### Added
 
-* TODO (or remove section if none)
+* Added support for rustflags set in a cargo config file.
 
 ### Changed
 
diff --git a/Cargo.lock b/Cargo.lock
index 8eef879..0398e45 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -90,6 +90,90 @@ version = "1.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "cf1de2fe8c75bc145a2f577add951f8134889b4795d47466a54a5c846d691693"
 
+[[package]]
+name = "bitmaps"
+version = "2.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "031043d04099746d8db04daf1fa424b2bc8bd69d92b25962dcde24da39ab64a2"
+dependencies = [
+ "typenum",
+]
+
+[[package]]
+name = "bstr"
+version = "0.2.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a40b47ad93e1a5404e6c18dec46b628214fee441c70f4ab5d6942142cc268a3d"
+dependencies = [
+ "memchr",
+]
+
+[[package]]
+name = "bytesize"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "81a18687293a1546b67c246452202bbbf143d239cb43494cc163da14979082da"
+
+[[package]]
+name = "cargo"
+version = "0.51.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bb7d89cbdcbeada632f64aa9f692e265852b0eb6ccdf3b1814716cc62101eeb6"
+dependencies = [
+ "anyhow",
+ "atty",
+ "bytesize",
+ "cargo-platform",
+ "clap",
+ "core-foundation",
+ "crates-io",
+ "crossbeam-utils",
+ "crypto-hash",
+ "curl",
+ "curl-sys",
+ "env_logger",
+ "filetime",
+ "flate2",
+ "fwdansi",
+ "git2",
+ "git2-curl",
+ "glob",
+ "hex 0.4.3",
+ "home",
+ "humantime",
+ "ignore",
+ "im-rc",
+ "jobserver",
+ "lazy_static",
+ "lazycell",
+ "libc",
+ "libgit2-sys",
+ "log",
+ "memchr",
+ "miow",
+ "num_cpus",
+ "opener",
+ "percent-encoding",
+ "rustc-workspace-hack",
+ "rustfix",
+ "same-file",
+ "semver 0.10.0",
+ "serde",
+ "serde_ignored",
+ "serde_json",
+ "shell-escape",
+ "strip-ansi-escapes",
+ "tar",
+ "tempfile",
+ "termcolor",
+ "toml",
+ "unicode-width",
+ "unicode-xid",
+ "url",
+ "walkdir",
+ "winapi",
+]
+
 [[package]]
 name = "cargo-binutils"
 version = "0.3.3"
@@ -113,6 +197,7 @@ version = "0.10.0"
 dependencies = [
  "anyhow",
  "assert_cmd",
+ "cargo",
  "cargo-binutils",
  "predicates",
  "structopt",
@@ -120,6 +205,15 @@ dependencies = [
  "toml",
 ]
 
+[[package]]
+name = "cargo-platform"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0226944a63d1bf35a3b5f948dd7c59e263db83695c9e8bffc4037de02e30f1d7"
+dependencies = [
+ "serde",
+]
+
 [[package]]
 name = "cargo_metadata"
 version = "0.11.4"
@@ -131,6 +225,15 @@ dependencies = [
  "serde_json",
 ]
 
+[[package]]
+name = "cc"
+version = "1.0.67"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e3c69b077ad434294d3ce9f1f6143a2a4b89a8a2d54ef813d85003a4fd1137fd"
+dependencies = [
+ "jobserver",
+]
+
 [[package]]
 name = "cfg-if"
 version = "1.0.0"
@@ -152,6 +255,118 @@ dependencies = [
  "vec_map",
 ]
 
+[[package]]
+name = "commoncrypto"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d056a8586ba25a1e4d61cb090900e495952c7886786fc55f909ab2f819b69007"
+dependencies = [
+ "commoncrypto-sys",
+]
+
+[[package]]
+name = "commoncrypto-sys"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1fed34f46747aa73dfaa578069fd8279d2818ade2b55f38f22a9401c7f4083e2"
+dependencies = [
+ "libc",
+]
+
+[[package]]
+name = "core-foundation"
+version = "0.9.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0a89e2ae426ea83155dccf10c0fa6b1463ef6d5fcb44cee0b224a408fa640a62"
+dependencies = [
+ "core-foundation-sys",
+ "libc",
+]
+
+[[package]]
+name = "core-foundation-sys"
+version = "0.8.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ea221b5284a47e40033bf9b66f35f984ec0ea2931eb03505246cd27a963f981b"
+
+[[package]]
+name = "crates-io"
+version = "0.31.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "09f977948a46e9edf93eb3dc2d7a8dd4ce3105d36de63300befed37cdf051d4a"
+dependencies = [
+ "anyhow",
+ "curl",
+ "percent-encoding",
+ "serde",
+ "serde_derive",
+ "serde_json",
+ "url",
+]
+
+[[package]]
+name = "crc32fast"
+version = "1.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "81156fece84ab6a9f2afdb109ce3ae577e42b1228441eded99bd77f627953b1a"
+dependencies = [
+ "cfg-if",
+]
+
+[[package]]
+name = "crossbeam-utils"
+version = "0.8.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e7e9d99fa91428effe99c5c6d4634cdeba32b8cf784fc428a2a687f61a952c49"
+dependencies = [
+ "autocfg",
+ "cfg-if",
+ "lazy_static",
+]
+
+[[package]]
+name = "crypto-hash"
+version = "0.3.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8a77162240fd97248d19a564a565eb563a3f592b386e4136fb300909e67dddca"
+dependencies = [
+ "commoncrypto",
+ "hex 0.3.2",
+ "openssl",
+ "winapi",
+]
+
+[[package]]
+name = "curl"
+version = "0.4.35"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5a872858e9cb9e3b96c80dd78774ad9e32e44d3b05dc31e142b858d14aebc82c"
+dependencies = [
+ "curl-sys",
+ "libc",
+ "openssl-probe",
+ "openssl-sys",
+ "schannel",
+ "socket2",
+ "winapi",
+]
+
+[[package]]
+name = "curl-sys"
+version = "0.4.41+curl-7.75.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0ec466abd277c7cab2905948f3e94d10bc4963f1f5d47921c1cc4ffd2028fe65"
+dependencies = [
+ "cc",
+ "libc",
+ "libnghttp2-sys",
+ "libz-sys",
+ "openssl-sys",
+ "pkg-config",
+ "vcpkg",
+ "winapi",
+]
+
 [[package]]
 name = "difference"
 version = "2.0.0"
@@ -164,6 +379,19 @@ version = "0.3.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "fea41bba32d969b513997752735605054bc0dfa92b4c56bf1189f2e174be7a10"
 
+[[package]]
+name = "env_logger"
+version = "0.8.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "17392a012ea30ef05a610aa97dfb49496e71c9f676b27879922ea5bdf60d9d3f"
+dependencies = [
+ "atty",
+ "humantime",
+ "log",
+ "regex",
+ "termcolor",
+]
+
 [[package]]
 name = "escargot"
 version = "0.5.1"
@@ -198,6 +426,31 @@ dependencies = [
  "synstructure",
 ]
 
+[[package]]
+name = "filetime"
+version = "0.2.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1d34cfa13a63ae058bfa601fe9e313bbdb3746427c1459185464ce0fcf62e1e8"
+dependencies = [
+ "cfg-if",
+ "libc",
+ "redox_syscall",
+ "winapi",
+]
+
+[[package]]
+name = "flate2"
+version = "1.0.20"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cd3aec53de10fe96d7d8c565eb17f2c687bb5518a2ec453b5b1252964526abe0"
+dependencies = [
+ "cfg-if",
+ "crc32fast",
+ "libc",
+ "libz-sys",
+ "miniz_oxide",
+]
+
 [[package]]
 name = "float-cmp"
 version = "0.8.0"
@@ -207,6 +460,47 @@ dependencies = [
  "num-traits",
 ]
 
+[[package]]
+name = "fnv"
+version = "1.0.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3f9eec918d3f24069decb9af1554cad7c880e2da24a9afd88aca000531ab82c1"
+
+[[package]]
+name = "foreign-types"
+version = "0.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f6f339eb8adc052cd2ca78910fda869aefa38d22d5cb648e6485e4d3fc06f3b1"
+dependencies = [
+ "foreign-types-shared",
+]
+
+[[package]]
+name = "foreign-types-shared"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "00b0228411908ca8685dba7fc2cdd70ec9990a6e753e89b6ac91a84c40fbaf4b"
+
+[[package]]
+name = "form_urlencoded"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5fc25a87fa4fd2094bffb06925852034d90a17f0d1e05197d4956d3555752191"
+dependencies = [
+ "matches",
+ "percent-encoding",
+]
+
+[[package]]
+name = "fwdansi"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "08c1f5787fe85505d1f7777268db5103d80a7a374d2316a7ce262e57baf8f208"
+dependencies = [
+ "memchr",
+ "termcolor",
+]
+
 [[package]]
 name = "getrandom"
 version = "0.2.2"
@@ -224,6 +518,52 @@ version = "0.23.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f6503fe142514ca4799d4c26297c4248239fe8838d827db6bd6065c6ed29a6ce"
 
+[[package]]
+name = "git2"
+version = "0.13.17"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1d250f5f82326884bd39c2853577e70a121775db76818ffa452ed1e80de12986"
+dependencies = [
+ "bitflags",
+ "libc",
+ "libgit2-sys",
+ "log",
+ "openssl-probe",
+ "openssl-sys",
+ "url",
+]
+
+[[package]]
+name = "git2-curl"
+version = "0.14.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "883539cb0ea94bab3f8371a98cd8e937bbe9ee7c044499184aa4c17deb643a50"
+dependencies = [
+ "curl",
+ "git2",
+ "log",
+ "url",
+]
+
+[[package]]
+name = "glob"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9b919933a397b79c37e33b77bb2aa3dc8eb6e165ad809e58ff75bc7db2e34574"
+
+[[package]]
+name = "globset"
+version = "0.4.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c152169ef1e421390738366d2f796655fec62621dabbd0fd476f905934061e4a"
+dependencies = [
+ "aho-corasick",
+ "bstr",
+ "fnv",
+ "log",
+ "regex",
+]
+
 [[package]]
 name = "heck"
 version = "0.3.2"
@@ -242,24 +582,159 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "hex"
+version = "0.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "805026a5d0141ffc30abb3be3173848ad46a1b1664fe632428479619a3644d77"
+
+[[package]]
+name = "hex"
+version = "0.4.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7f24254aa9a54b5c858eaee2f5bccdb46aaf0e486a595ed5fd8f86ba55232a70"
+
+[[package]]
+name = "home"
+version = "0.5.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2456aef2e6b6a9784192ae780c0f15bc57df0e918585282325e8c8ac27737654"
+dependencies = [
+ "winapi",
+]
+
+[[package]]
+name = "humantime"
+version = "2.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9a3a5bfb195931eeb336b2a7b4d761daec841b97f947d34394601737a7bba5e4"
+
+[[package]]
+name = "idna"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "89829a5d69c23d348314a7ac337fe39173b61149a9864deabd260983aed48c21"
+dependencies = [
+ "matches",
+ "unicode-bidi",
+ "unicode-normalization",
+]
+
+[[package]]
+name = "ignore"
+version = "0.4.17"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b287fb45c60bb826a0dc68ff08742b9d88a2fea13d6e0c286b3172065aaf878c"
+dependencies = [
+ "crossbeam-utils",
+ "globset",
+ "lazy_static",
+ "log",
+ "memchr",
+ "regex",
+ "same-file",
+ "thread_local",
+ "walkdir",
+ "winapi-util",
+]
+
+[[package]]
+name = "im-rc"
+version = "15.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3ca8957e71f04a205cb162508f9326aea04676c8dfd0711220190d6b83664f3f"
+dependencies = [
+ "bitmaps",
+ "rand_core 0.5.1",
+ "rand_xoshiro",
+ "sized-chunks",
+ "typenum",
+ "version_check",
+]
+
 [[package]]
 name = "itoa"
 version = "0.4.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "dd25036021b0de88a0aff6b850051563c6516d0bf53f8638938edbb9de732736"
 
+[[package]]
+name = "jobserver"
+version = "0.1.21"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5c71313ebb9439f74b00d9d2dcec36440beaf57a6aa0623068441dd7cd81a7f2"
+dependencies = [
+ "libc",
+]
+
 [[package]]
 name = "lazy_static"
 version = "1.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
 
+[[package]]
+name = "lazycell"
+version = "1.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "830d08ce1d1d941e6b30645f1a0eb5643013d835ce3779a5fc208261dbe10f55"
+
 [[package]]
 name = "libc"
 version = "0.2.87"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "265d751d31d6780a3f956bb5b8022feba2d94eeee5a84ba64f4212eedca42213"
 
+[[package]]
+name = "libgit2-sys"
+version = "0.12.18+1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3da6a42da88fc37ee1ecda212ffa254c25713532980005d5f7c0b0fbe7e6e885"
+dependencies = [
+ "cc",
+ "libc",
+ "libssh2-sys",
+ "libz-sys",
+ "openssl-sys",
+ "pkg-config",
+]
+
+[[package]]
+name = "libnghttp2-sys"
+version = "0.1.6+1.43.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0af55541a8827e138d59ec9e5877fb6095ece63fb6f4da45e7491b4fbd262855"
+dependencies = [
+ "cc",
+ "libc",
+]
+
+[[package]]
+name = "libssh2-sys"
+version = "0.2.21"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e0186af0d8f171ae6b9c4c90ec51898bad5d08a2d5e470903a50d9ad8959cbee"
+dependencies = [
+ "cc",
+ "libc",
+ "libz-sys",
+ "openssl-sys",
+ "pkg-config",
+ "vcpkg",
+]
+
+[[package]]
+name = "libz-sys"
+version = "1.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "602113192b08db8f38796c4e85c39e960c145965140e918018bcde1952429655"
+dependencies = [
+ "cc",
+ "libc",
+ "pkg-config",
+ "vcpkg",
+]
+
 [[package]]
 name = "log"
 version = "0.4.14"
@@ -269,6 +744,12 @@ dependencies = [
  "cfg-if",
 ]
 
+[[package]]
+name = "matches"
+version = "0.1.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7ffc5c5338469d4d3ea17d269fa8ea3512ad247247c30bd2df69e68309ed0a08"
+
 [[package]]
 name = "memchr"
 version = "2.3.4"
@@ -285,6 +766,15 @@ dependencies = [
  "autocfg",
 ]
 
+[[package]]
+name = "miow"
+version = "0.3.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b9f1c5b025cda876f66ef43a113f91ebc9f4ccef34843000e0adf6ebbab84e21"
+dependencies = [
+ "winapi",
+]
+
 [[package]]
 name = "normalize-line-endings"
 version = "0.3.0"
@@ -300,6 +790,16 @@ dependencies = [
  "autocfg",
 ]
 
+[[package]]
+name = "num_cpus"
+version = "1.13.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "05499f3756671c15885fee9034446956fff3f243d6077b91e5767df161f766b3"
+dependencies = [
+ "hermit-abi",
+ "libc",
+]
+
 [[package]]
 name = "object"
 version = "0.23.0"
@@ -312,6 +812,60 @@ version = "1.7.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "af8b08b04175473088b46763e51ee54da5f9a164bc162f615b91bc179dbf15a3"
 
+[[package]]
+name = "opener"
+version = "0.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "13117407ca9d0caf3a0e74f97b490a7e64c0ae3aa90a8b7085544d0c37b6f3ae"
+dependencies = [
+ "winapi",
+]
+
+[[package]]
+name = "openssl"
+version = "0.10.33"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a61075b62a23fef5a29815de7536d940aa35ce96d18ce0cc5076272db678a577"
+dependencies = [
+ "bitflags",
+ "cfg-if",
+ "foreign-types",
+ "libc",
+ "once_cell",
+ "openssl-sys",
+]
+
+[[package]]
+name = "openssl-probe"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "77af24da69f9d9341038eba93a073b1fdaaa1b788221b00a69bce9e762cb32de"
+
+[[package]]
+name = "openssl-sys"
+version = "0.9.61"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "313752393519e876837e09e1fa183ddef0be7735868dced3196f4472d536277f"
+dependencies = [
+ "autocfg",
+ "cc",
+ "libc",
+ "pkg-config",
+ "vcpkg",
+]
+
+[[package]]
+name = "percent-encoding"
+version = "2.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d4fd5641d01c8f18a23da7b6fe29298ff4b55afcccdf78973b24cf3175fee32e"
+
+[[package]]
+name = "pkg-config"
+version = "0.3.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3831453b3449ceb48b6d9c7ad7c96d5ea673e9b470a1dc578c2ce6521230884c"
+
 [[package]]
 name = "ppv-lite86"
 version = "0.2.10"
@@ -397,7 +951,7 @@ checksum = "0ef9e7e66b4468674bfcb0c81af8b7fa0bb154fa9f28eb840da5c447baeb8d7e"
 dependencies = [
  "libc",
  "rand_chacha",
- "rand_core",
+ "rand_core 0.6.2",
  "rand_hc",
 ]
 
@@ -408,9 +962,15 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e12735cf05c9e10bf21534da50a147b924d555dc7a547c42e6bb2d5b6017ae0d"
 dependencies = [
  "ppv-lite86",
- "rand_core",
+ "rand_core 0.6.2",
 ]
 
+[[package]]
+name = "rand_core"
+version = "0.5.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "90bde5296fc891b0cef12a6d03ddccc162ce7b2aff54160af9338f8d40df6d19"
+
 [[package]]
 name = "rand_core"
 version = "0.6.2"
@@ -426,7 +986,16 @@ version = "0.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3190ef7066a446f2e7f42e239d161e905420ccab01eb967c9eb27d21b2322a73"
 dependencies = [
- "rand_core",
+ "rand_core 0.6.2",
+]
+
+[[package]]
+name = "rand_xoshiro"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a9fcdd2e881d02f1d9390ae47ad8e5696a9e4be7b547a1da2afbc61973217004"
+dependencies = [
+ "rand_core 0.5.1",
 ]
 
 [[package]]
@@ -480,6 +1049,12 @@ version = "0.1.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6e3bad0ee36814ca07d7968269dd4b7ec89ec2da10c4bb613928d3077083c232"
 
+[[package]]
+name = "rustc-workspace-hack"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fc71d2faa173b74b232dedc235e3ee1696581bb132fc116fa3626d6151a1a8fb"
+
 [[package]]
 name = "rustc_version"
 version = "0.2.3"
@@ -489,12 +1064,43 @@ dependencies = [
  "semver 0.9.0",
 ]
 
+[[package]]
+name = "rustfix"
+version = "0.5.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f2c50b74badcddeb8f7652fa8323ce440b95286f8e4b64ebfd871c609672704e"
+dependencies = [
+ "anyhow",
+ "log",
+ "serde",
+ "serde_json",
+]
+
 [[package]]
 name = "ryu"
 version = "1.0.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "71d301d4193d031abdd79ff7e3dd721168a9572ef3fe51a1517aba235bd8f86e"
 
+[[package]]
+name = "same-file"
+version = "1.0.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "93fc1dc3aaa9bfed95e02e6eadabb4baf7e3078b0bd1b4d7b6b0b68378900502"
+dependencies = [
+ "winapi-util",
+]
+
+[[package]]
+name = "schannel"
+version = "0.1.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8f05ba609c234e60bee0d547fe94a4c7e9da733d1c962cf6e59efa4cd9c8bc75"
+dependencies = [
+ "lazy_static",
+ "winapi",
+]
+
 [[package]]
 name = "semver"
 version = "0.9.0"
@@ -540,6 +1146,15 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "serde_ignored"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1c2c7d39d14f2f2ea82239de71594782f186fd03501ac81f0ce08e674819ff2f"
+dependencies = [
+ "serde",
+]
+
 [[package]]
 name = "serde_json"
 version = "1.0.64"
@@ -551,6 +1166,42 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "shell-escape"
+version = "0.1.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "45bb67a18fa91266cc7807181f62f9178a6873bfad7dc788c42e6430db40184f"
+
+[[package]]
+name = "sized-chunks"
+version = "0.6.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "65e65d6a9f13cd78f361ea5a2cf53a45d67cdda421ba0316b9be101560f3d207"
+dependencies = [
+ "bitmaps",
+ "typenum",
+]
+
+[[package]]
+name = "socket2"
+version = "0.3.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "122e570113d28d773067fab24266b66753f6ea915758651696b6e35e49f88d6e"
+dependencies = [
+ "cfg-if",
+ "libc",
+ "winapi",
+]
+
+[[package]]
+name = "strip-ansi-escapes"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9d63676e2abafa709460982ddc02a3bb586b6d15a49b75c212e06edd3933acee"
+dependencies = [
+ "vte",
+]
+
 [[package]]
 name = "strsim"
 version = "0.8.0"
@@ -604,6 +1255,16 @@ dependencies = [
  "unicode-xid",
 ]
 
+[[package]]
+name = "tar"
+version = "0.4.33"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c0bcfbd6a598361fda270d82469fff3d65089dc33e175c9a131f7b4cd395f228"
+dependencies = [
+ "filetime",
+ "libc",
+]
+
 [[package]]
 name = "tempfile"
 version = "3.2.0"
@@ -618,6 +1279,15 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "termcolor"
+version = "1.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2dfed899f0eb03f32ee8c6a0aabdb8a7949659e3466561fc0adf54e26d88c5f4"
+dependencies = [
+ "winapi-util",
+]
+
 [[package]]
 name = "textwrap"
 version = "0.11.0"
@@ -636,6 +1306,21 @@ dependencies = [
  "once_cell",
 ]
 
+[[package]]
+name = "tinyvec"
+version = "1.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "317cca572a0e89c3ce0ca1f1bdc9369547fe318a683418e42ac8f59d14701023"
+dependencies = [
+ "tinyvec_macros",
+]
+
+[[package]]
+name = "tinyvec_macros"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cda74da7e1a664f795bb1f8a87ec406fb89a02522cf6e50620d016add6dbbf5c"
+
 [[package]]
 name = "toml"
 version = "0.5.8"
@@ -651,6 +1336,30 @@ version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a7f741b240f1a48843f9b8e0444fb55fb2a4ff67293b50a9179dfd5ea67f8d41"
 
+[[package]]
+name = "typenum"
+version = "1.13.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "879f6906492a7cd215bfa4cf595b600146ccfac0c79bcbd1f3000162af5e8b06"
+
+[[package]]
+name = "unicode-bidi"
+version = "0.3.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "49f2bd0c6468a8230e1db229cff8029217cf623c767ea5d60bfbd42729ea54d5"
+dependencies = [
+ "matches",
+]
+
+[[package]]
+name = "unicode-normalization"
+version = "0.1.17"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "07fbfce1c8a97d547e8b5334978438d9d6ec8c20e38f56d4a4374d181493eaef"
+dependencies = [
+ "tinyvec",
+]
+
 [[package]]
 name = "unicode-segmentation"
 version = "1.7.1"
@@ -669,6 +1378,30 @@ version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f7fe0bb3479651439c9112f72b6c505038574c9fbb575ed1bf3b797fa39dd564"
 
+[[package]]
+name = "url"
+version = "2.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9ccd964113622c8e9322cfac19eb1004a07e636c545f325da085d5cdde6f1f8b"
+dependencies = [
+ "form_urlencoded",
+ "idna",
+ "matches",
+ "percent-encoding",
+]
+
+[[package]]
+name = "utf8parse"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8772a4ccbb4e89959023bc5b7cb8623a795caa7092d99f3aa9501b9484d4557d"
+
+[[package]]
+name = "vcpkg"
+version = "0.2.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b00bca6106a5e23f3eee943593759b7fcddb00554332e856d990c893966879fb"
+
 [[package]]
 name = "vec_map"
 version = "0.8.2"
@@ -681,6 +1414,15 @@ version = "0.9.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b5a972e5669d67ba988ce3dc826706fb0a8b01471c088cb0b6110b805cc36aed"
 
+[[package]]
+name = "vte"
+version = "0.3.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4f42f536e22f7fcbb407639765c8fd78707a33109301f834a594758bedd6e8cf"
+dependencies = [
+ "utf8parse",
+]
+
 [[package]]
 name = "wait-timeout"
 version = "0.2.0"
@@ -690,6 +1432,17 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "walkdir"
+version = "2.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "808cf2735cd4b6866113f648b791c6adc5714537bc222d9347bb203386ffda56"
+dependencies = [
+ "same-file",
+ "winapi",
+ "winapi-util",
+]
+
 [[package]]
 name = "wasi"
 version = "0.10.0+wasi-snapshot-preview1"
@@ -712,6 +1465,15 @@ version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ac3b87c63620426dd9b991e5ce0329eff545bccbbb34f3be09ff6fb6ab51b7b6"
 
+[[package]]
+name = "winapi-util"
+version = "0.1.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "70ec6ce85bb158151cae5e5c87f95a8e97d2c0c4b001223f33a334e3ce5de178"
+dependencies = [
+ "winapi",
+]
+
 [[package]]
 name = "winapi-x86_64-pc-windows-gnu"
 version = "0.4.0"
diff --git a/Cargo.toml b/Cargo.toml
index 260b20c..b36a99e 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -15,6 +15,7 @@ structopt = "0.3.5"
 tempfile = "3.1.0"
 toml = "0.5.5"
 cargo-binutils = "0.3.3"
+cargo = "0.51.0"
 
 [workspace]
 members = ["."]
diff --git a/src/project.rs b/src/project.rs
index 794aab5..0c1a950 100644
--- a/src/project.rs
+++ b/src/project.rs
@@ -1,6 +1,13 @@
 use crate::options::{self, BuildOptions, Sanitizer};
 use crate::utils::default_target;
 use anyhow::{anyhow, bail, Context, Result};
+use cargo::{
+    core::{
+        compiler::{CompileKind, CompileTarget, RustcTargetData},
+        Workspace,
+    },
+    CargoResult,
+};
 use std::collections::HashSet;
 use std::io::Read;
 use std::io::Write;
@@ -201,7 +208,7 @@ impl FuzzProject {
             rustflags.push_str(" -C codegen-units=1");
         }
 
-        if let Ok(other_flags) = env::var("RUSTFLAGS") {
+        if let Ok(other_flags) = cargo_rustflags(&self.manifest_path(), &build.triple) {
             rustflags.push_str(" ");
             rustflags.push_str(&other_flags);
         }
@@ -881,3 +888,13 @@ fn strip_current_dir_prefix(path: &Path) -> &Path {
         .and_then(|curdir| path.strip_prefix(curdir).ok())
         .unwrap_or(&path)
 }
+
+fn cargo_rustflags(manifest_path: &Path, target: &str) -> CargoResult<String> {
+    let config = cargo::Config::default()?;
+    let ws = Workspace::new(manifest_path, &config)?;
+    let target = CompileTarget::new(target)?;
+    let kind = CompileKind::Target(target);
+    let target_data = RustcTargetData::new(&ws, &[kind])?;
+
+    Ok(target_data.info(kind).rustflags.join(" "))
+}